Dissertationen zum Thema „Squeezed light“
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1
Ward, Martin B. „Squeezed light in semiconductors“. Thesis, University of Oxford, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270175.
2
Scott, Martin. „Atom : squeezed light interactions“. Thesis, Queen's University Belfast, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268311.
3
Schucan, Gian-Mattia. „Generation of squeezed light in semiconductors“. Thesis, University of Oxford, 1999. http://ora.ox.ac.uk/objects/uuid:417b1d31-8d25-42db-b707-32bd460b4183.
Annotation:
We present experimental studies based on all three methods by which the generation of squeezed light in semiconductors has thus far been demonstrated experimentally: Fourwave mixing, multi-photon absorption and direct generation at the source. Four-wave mixing was used to generate femtosecond-pulsed quadrature squeezed light by cross-phase modulation in single-crystal hexagonal CdSe at wavelengths between 1.42 and 1.55 μm. We measured 0.4 dB squeezing (1.1 dB is inferred at the crystal) using 100 fs pulses. The wavelength and the intensity dependence, as well as variations in the local oscillator configuration were investigated. At higher intensities squeezing was shown to deteriorate owing to competing nonlinear processes. We also characterised the nonlinear optical properties of CdSe in this wavelengths range using an interferometric autocorrelator. In addition, we studied the feasibility of extending this technique to AlGaAs waveguides. The key problems are addressed and solutions are proposed. In a different experiment we used an AlGaAs waveguide to demonstrate for the first time photon-number squeezing by multi-photon absorption. By tuning the pump energy through the half bandgap energy we could effectively select two- or three-photon absorption as the dominant mechanism. Squeezing by these two mechanisms could be clearly distinguished and was found to be in good agreement with longstanding theoretical predictions. We also established the generality of the effect, by demonstrating the same mechanism in organic semiconductors, where it led to the first ever observation of squeezed light in an organic material. Finally, we present our measurements of photon-number squeezing in high-efficiency double heterojunction AlGaAs light-emitting diodes. We measured squeezing of up to 2.0 dB. In addition, we observed quantum noise correlations when several of these devices were connected in series.
4
Zhou, Peng. „Interactions of atoms with squeezed light“. Thesis, Queen's University Belfast, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337055.
5
Lyubomirsky, Ilya. „Quantum reality and squeezed states of light“. Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/36431.
Annotation:
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1994.Includes bibliographical references (leaves 67-71).
by Ilya Lyubomirsky.
M.S.
6
Daly, Elizabeth Marion. „Generation, measurement, and application of pulsed squeezed light“. Thesis, University of Strathclyde, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367066.
7
Nee, Phillip Tsefung. „Generation of squeezed light via second harmonic generation“. Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/34050.
8
Ast, Stefan [Verfasser]. „New approaches in squeezed light generation : quantum states of light with GHz squeezing bandwidth and squeezed light generation via the cascaded Kerr effect / Stefan Ast“. Hannover : Technische Informationsbibliothek und Universitätsbibliothek Hannover (TIB), 2015. http://d-nb.info/1072062666/34.
9
Lam, Ping Koy, und Ping Lam@anu edu au. „Applications of Quantum Electro-Optic Control and Squeezed Light“. The Australian National University. Faculty of Science, 1999. http://thesis.anu.edu.au./public/adt-ANU20030611.170800.
Annotation:
In this thesis, we report the observations of optical squeezing from second harmonic generation (SHG), optical parametric oscillation (OPO) and optical parametric amplification (OPA). Demonstrations and proposals of applications involving the squeezed light and electro-optic control loops are presented.
¶
In our SHG setup, we report the observation of 2.1 dB of intensity squeezing on the second harmonic (SH) output. Investigations into the system show that the squeezing performance of a SHG system is critically affected by the pump noise and a modular theory of noise propagation is developed to describe and quantify this effect. Our experimental data has also shown that in a low-loss SHG system, intra-cavity nondegenerate OPO modes can simultaneously occur. This competition of nonlinear processes leads to the optical clamping of the SH output power and in general can degrade the SH squeezing. We model this competition and show that it imposes a limit to the observable SH squeezing. Proposals for minimizing the effect of competition are presented.
¶
In our OPO setup, we report the observation of 7.1 dB of vacuum squeezing and more than 4 dB of intensity squeezing when the OPO is operating as a parametric amplifier. We present the design criteria and discuss the limits to the observable squeezing from the OPO.We attribute the large amount of squeezing obtained in our experiment to the high escape efficiency of the OPO. The effect of phase jitter on the squeezing of the vacuum state is modeled.
¶
The quantum noise performance of an electro-optic feedforward control loop is investigated. With classical coherent inputs, we demonstrate that vacuum fluctuations introduced at the beam splitter of the control loop can be completely cancelled by an optimum amount of positive feedforward. The cancellation of vacuum fluctuations leads to the possibility of noiseless signal amplification with the feedforward loop. Comparison shows that the feedforward amplifier is superior or at least comparable in performance with other noiseless amplification schemes. When combined with an injection-locked non-planar ring Nd:YAG laser, we demonstrate that signal and power amplifications can both be noiseless and independently variable.
¶
Using squeezed inputs to the feedforward control loop, we demonstrate that information carrying squeezed states can be made robust to large downstream transmission losses via a noiseless signal amplification. We show that the combination of a squeezed vacuum meter input and a feedforward loop is a quantum nondemolition (QND) device, with the feedforward loop providing an additional improvement on the transfer of signal. In general, the use of a squeezed vacuum meter input and an electro-optic feedforward loop can provide pre- and post- enhancements to many existing QND schemes.
¶
Finally, we proposed that the quantum teleportation of a continuous-wave optical state can be achieved using a pair of phase and amplitude electro-optic feedforward loops with two orthogonal quadrature squeezed inputs. The signal transfer and quantum correlation of the teleported optical state are analysed. We show that a two dimensional diagram, similar to the QND figures of merits, can be used to quantify the performance of a teleporter.
10
Leonardi, Matteo. „Development of a squeezed light source prototype for Advanced Virgo“. Doctoral thesis, Università degli studi di Trento, 2016. https://hdl.handle.net/11572/369305.
Annotation:
A century after the prediction of the existence of gravitational waves by A. Einstein and after over fifty years of experimental efforts, gravitational waves have been detected at Earth directly. This result is a major achievement and opens new prospectives for the exploration of our universe. Gravitational waves carry different and complementary information about the source with respect to electromagnetic signals. In particular the first detection demonstrated the existence of stellar-mass black holes, binary systems of black holes and their coalescence.
The detection was made by the LIGO instruments which are twin kilometer-scale Michelson interferometers in the US. These detectors represent the second generation of gravitational wave interferometers and, for the first time, they achieved the outstanding strain sensitivity of 10^(-23) Hz^(-1/2) between 90Hz and 400Hz. In the next months the LIGO network will be joined by another second generation detector: Advanced Virgo located near Pisa, Italy. The sensitivity of these advanced detectors is set by different noise sources. In particular, in the low frequency range (below 100Hz) major contributions come from thermal noises, gravity gradient noise and radiation pressure noise; instead, the high frequency band (above 100-200Hz) is dominated by shot noise. Quantum noise (radiation pressure and shot noise) is expected to dominate the detector sensitivity in the whole frequency band at the final target laser input power. To decrease the shot noise while increasing the radiation-pressure noise, or vice-versa, Caves \cite{Caves1981} proposed in 1981 the idea of the squeezed-state technique. The LIGO collaboration demonstrated for the first time in 2011 that the injection of a squeezed vacuum state into the dark port of the interferometer can reduce the shot noise due to the quantum nature of light. This result was achieved with the German-British interferometer GEO600 and was replicated in 2013 with the LIGO interferometer at Livingston. After these results, the LIGO collaboration have pursued further the research in the squeezed-state technique which is considered mandatory for third generation of ground based interferometric detectors. In 2013, the Virgo collaboration started developing the squeezed-state technique. The subject of my thesis is the realization of a prototype of frequency independent squeezed vacuum state source to be injected in Advanced Virgo. This prototype is developed in collaboration with other Virgo groups.
11
Leonardi, Matteo. „Development of a squeezed light source prototype for Advanced Virgo“. Doctoral thesis, University of Trento, 2016. http://eprints-phd.biblio.unitn.it/1843/1/phd_thesis-LeonardiMatteo.pdf.
Annotation:
A century after the prediction of the existence of gravitational waves by A. Einstein and after over fifty years of experimental efforts, gravitational waves have been detected at Earth directly. This result is a major achievement and opens new prospectives for the exploration of our universe. Gravitational waves carry different and complementary information about the source with respect to electromagnetic signals. In particular the first detection demonstrated the existence of stellar-mass black holes, binary systems of black holes and their coalescence.
The detection was made by the LIGO instruments which are twin kilometer-scale Michelson interferometers in the US. These detectors represent the second generation of gravitational wave interferometers and, for the first time, they achieved the outstanding strain sensitivity of 10^(-23) Hz^(-1/2) between 90Hz and 400Hz. In the next months the LIGO network will be joined by another second generation detector: Advanced Virgo located near Pisa, Italy. The sensitivity of these advanced detectors is set by different noise sources. In particular, in the low frequency range (below 100Hz) major contributions come from thermal noises, gravity gradient noise and radiation pressure noise; instead, the high frequency band (above 100-200Hz) is dominated by shot noise. Quantum noise (radiation pressure and shot noise) is expected to dominate the detector sensitivity in the whole frequency band at the final target laser input power. To decrease the shot noise while increasing the radiation-pressure noise, or vice-versa, Caves \cite{Caves1981} proposed in 1981 the idea of the squeezed-state technique. The LIGO collaboration demonstrated for the first time in 2011 that the injection of a squeezed vacuum state into the dark port of the interferometer can reduce the shot noise due to the quantum nature of light. This result was achieved with the German-British interferometer GEO600 and was replicated in 2013 with the LIGO interferometer at Livingston. After these results, the LIGO collaboration have pursued further the research in the squeezed-state technique which is considered mandatory for third generation of ground based interferometric detectors. In 2013, the Virgo collaboration started developing the squeezed-state technique. The subject of my thesis is the realization of a prototype of frequency independent squeezed vacuum state source to be injected in Advanced Virgo. This prototype is developed in collaboration with other Virgo groups.
12
Wölfl, Friedrich. „Intensity noise studies of semiconductor light emitters“. Thesis, University of Oxford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342990.
13
Predojevic, Ana. „Rubidium resonant squeezed light from a diode-pumped optical-parametric oscillator“. Doctoral thesis, Universitat Politècnica de Catalunya, 2009. http://hdl.handle.net/10803/6592.
Annotation:
La luz comprimida (squeezed light) es uno de los componentes importantes de los experimentos de memorias cuánticas. Un almacenamiento eficientede la luz comprimida en una colectividad de átomos exige que la luz (comprimida) sea resonante a la línea espectral de absorción. El láser de diodo
puede acceder a una amplia clase de líneas espectrales dado al amplio rango de longitudes de onda accesibles. Por lo tanto, el uso de fuentes de luz comprimida basadas en láseres de diodo ampliaría el número de los posibles experimentos. Además, los láseres de diodo reúnen muchas buenas
características como son su construcción robusta y compacta, simplicidad y bajo precio. La única desventaja de los láseres diodo es el ruido de la fase que resulta en un ensanchamiento de sus líneas espectrales.
Esta tesis describe estudios experimentales y teóricos de generación de estados de luz omprimida en cuadratura y polarización, adecuados para la
interacción con átomos de rubidio. En ese ocumento damos una atención especial al ruido de fase y sus efectos en el grado de compresión de la luz
y los métodos para lograr luz comprimida en presencia de ruido de fase generado en el láser de diodo.
La tesis está estructurada de la siguiente manera:
El primer capítulo presenta las ideas generales de la conversión paramétrica de frecuencia (parametric downconversion) en un oscilador paramétrico
óptico. Aquí derivamos la descripción teórica de la luz comprimida en un oscilador paramétrico óptico operado por debajo del nivel umbral.
El segundo capítulo describe el aparato experimental. Primero, damos una descripción detallada del diseño de la cavidad paramétrica óptica y
resumimos las propiedades del cristal no lineal. A continuación, pasamos a describir el láser y los sistemas usados para la estabilización del sistema
láser y de la cavidad del oscilador. En el tercero se discute la ganancia de amplificación y la eficiencia de detección. Por último damos una descripción
general del experimento y presentamos los resultados en la compresión cuántica ("squeezing") de la luz.
El último capítulo analiza los efectos de ruido de fase en el "squeezing" de cuadratura y describe una técnica para eliminar su efecto. Primero,
discutimos el origen del ruido de fase para sistemas de láser de diodo. Segundo, derivamos el grado observable de "squeezing", teniendo en cuenta
los efectos de fluctuaciones cuasi-estacionarias de frecuencia. Por último, mostramos cómo los efectos del ruido de fase pueden ser eliminados y
comparamos la predicción teórica con nuestros resultados experimentales.
El resultado de este proyecto es una fuente de luz no-clásica resonante con la transición atómica del rubidio. Caracterizamos el "squeezing" del estado
de vacío cuántico resultante. El máximo grado de compresión logrado en el experimento fue 2.5dB por debajo del nivel de ruido cuántico. Además
realizamos un análisis del efecto que el ruido de fase tiene en el grado de compresión. Los resultados de este análisis mostraron que en presencia de
ruido de fase se espera que el "squeezing" dependa del retardo relativo entre el haz de luz comprimida y el oscilador local. Comprobamos
experimentalmente esta hipótesis y medimos el grado de compresión como una función del retardo entre la luz comprimida y el oscilador local. Los
resultados experimentales obtenidos fueron consistentes con la teoría.
Aparte de construir una fuente luz comprimida resonante con rubidio, hemos probado que el láser de diodo es una fuente adecuada para la producción
de luz comprimida. Hemos proporcionado una teoría que trata el efecto de ruido de fase en el grado de compresión de la luz en un oscilador
paramétrico óptico. El aparato experimental presentado aquí utiliza técnicas estándar que podrían ser aplicadas a una variedad de otras longitudes de ondas.
This thesis describes experimental and theoretical studies of generation of quadrature- and polarization-squeezed light suitable for interaction with rubidium atoms. Special attention is paid to phase noise, its effects on squeezing, and methods to achieve squeezing in the presence of diode laser phase noise.
Squeezed light is an important component of quantum memories experiments. Efficient storage of (squeezed) light in atomic ensembles requires the
light to be resonant to the respective atomic transition. Diode lasers can access many atomic transitions as they cover significantly broader wavelength
range than other classes of lasers. Consequently, employing diode-laser-based squeezed light sources would broaden the range of possible quantum
memories experiments. Furthermore, diode lasers posses many attractive features like robustness, simplicity, compactness, and low price. The
drawback of the diode laser is it's excess phase noise, which results in a relatively large linewidth. This forms an obstacle for detection of phasesensitive quantum states such as quadrature squeezing.
The thesis is structured as follows:
The first chapter presents the general ideas on parametric downconversion in an optical parametric oscillator. Here we derive the theoretical description
of squeezing of the light field in a subthreshold optical parametric oscillator.
The second chapter describes the experimental apparatus. First, we give a detailed description of the design of the optical parametric oscillator cavity
and summarise the properties of the nonlinear crystal. In continuation, we describe the laser system and the locking systems used for the laser system
and the optical parametric oscillator cavity stabilisations. Third, we discuss the amplification gain and the detection efficiency. Finally, we give a full
overview of the experiment and we present the squeezing results.
The last chapter analyses the effects of phase noise on quadrature squeezing and describes a technique to eliminate its effect. First, we discuss the
origin of the phase noise for diode laser systems. Second, we derive the observable squeezing taking into account the effects of quasi-static frequency
fluctuations. Third, we show how the effects of the phase noise can be eliminated and, last but not least, we compare the theoretical prediction with our
experimental results.
The outcome of this project is a rubidium resonant source of non-classical light. We characterised the output squeezed vacuum state. The maximum
squeezing achieved in the experiment was 2.5dB below shot-noise level. Moreover, we performed an analysis of the effect the phase noise has on the
squeezing. The results of this analysis showed that in presence of phase noise we expected that the squeezing level would depend on the relative
delay between squeezing and local oscillator path. We experimentally tested this statement performing a measurement of squeezing as a function of
the delay between the squeezed light and the local oscillator. The experimental results were consistent with the theory.
Apart form building a source of rubidium resonant squeezed light we have proven that the diode laser is a source suitable for production of squeezed
light. We provided a theory which treats the effect of phase noise on squeezing in optical parametric oscillator.
The experimental squeezing apparatus presented here uses standard techniques which could be applied to a variety of other wavelengths.
14
Wolfgramm, Florian. „Atomic quantum metrology with narrowband entangled and squeezed states of light“. Doctoral thesis, Universitat Politècnica de Catalunya, 2012. http://hdl.handle.net/10803/98460.
Annotation:
The use of light, especially of laser light, is in many cases the most sensitive way to perform measurements. However, the highest sensitivity that can be achieved with laser light as probe is bounded by the standard quantum limit (SQL). As many instruments are approaching this fundamental limit, it becomes crucial to explore ways to overcome the SQL. Quantum metrology offers the possibilities to increase the sensitivities of the most accurate measurements beyond the SQL by using photonic quantum states of light as a tool. Two well-known classes of quantum states that provide a metrological advantage and break the SQL are squeezed states and a certain class of entangled states, called NOON states. While it is of special interest to apply these quantum states to atomic systems, such as atomic vapors, this requires quantum states of the highest quality in terms of purity, fidelity, brightness, and indistinguishability. Most importantly, for the probing of atomic systems, the quantum states need to be extremely narrowband to match the atomic linewidths. As NOON states are usually generated in a broadband spontaneous parametric down-conversion (SPDC) process, they are not compatible with narrowband atomic resonances.
The goal of this thesis was the generation of suitable narrowband entangled and squeezed quantum states of light and their application to atomic systems. To increase the rate of atom-resonant SPDC photons by orders of magnitude, we used a cavity-enhanced setup. Polarization-squeezed states and polarization-entangled NOON states were created. The spectral brightness of the generated NOON states is one of the highest of pairs of indistinguishable photons reported so far. The photon pairs were carefully characterized by full quantum state tomography showing high fidelities with a perfect NOON state. After filtering the photon source output by a novel filter based on the “interaction-free measurement” scheme, a cross-correlation measurement demonstrated its potential as a narrowband heralded single-photon source, needed for example in quantum information. To apply these states in a quantum metrology scheme and to show the metrological advantage, we chose an atomic magnetometer as a model system. The assembled shot-noise-limited magnetometer is based on the Faraday effect in a vapor of hot rubidium atoms. It could be demonstrated that both quantum states perform better in the magnetometer application than any classical state, i.e., they break the SQL. In the case of NOON states, this is the first use of multi-photon coherence in an atomic experiment. In addition to applications in quantum metrology, the presented techniques of quantum-light generation and filtering are also directly applicable to quantum information tasks, especially to the use in quantum memories.El uso de la luz, en particular la luz láser es, en muchos casos, el método que permite realizar mediciones de la manera más sensible. No obstante, la mayor sensibilidad que se puede conseguir gracias a la luz láser como sistema de sondeo queda delimitada por el límite cuántico estándar (SQL). Visto que muchos instrumentos se están acercando a este límite fundamental, es crucial explorar formas de superar el SQL. La metrología cuántica ofrece la posibilidad de incrementar la sensibilidad de las medidas más precisas más allá del SQL empleando los estados cuánticos de luz como herramienta. Dos categorías conocidas de estados cuánticos que brindan una ventaja metrológica y rompen con el SQL son los estados “comprimidos” y ciertas categorías de estados entrelazados llamados estados “NOON”. Aunque es de especial interés aplicar estos estados cuánticos a los sistemas atómicos, como a los vapores atómicos, se requieren estados cuánticos de óptima calidad en términos de pureza, fidelidad, luminosidad e identidad. Lo más importante para los sistemas atómicos de investigación es que los estados cuánticos sean de banda extremadamente estrecha para que coincidan con el ancho de banda de átomos. Puesto que los estados NOON suelen ser generados en un proceso de conversión espontánea paramétrica descendente (SPDC) de banda ancha, no son compatibles con las resonancias atómicas de banda estrecha. El objeto de esta tesis fue la generación de estados cuánticos de luz apropiados de banda estrecha, entrelazados y comprimidos, y su aplicación en los sistemas atómicos. Para incrementar el número de fotones generados por SPDC resonantes con la transición atómica por órdenes de magnitud, se empleó un sistema aumentado por un resonador. Se crearon estados de polarización comprimida y estados NOON de polarización entrelazada. La luminosidad espectral de los estados NOON generada supone una de las más altas que se hayan reportado hasta el momento entre pares de fotones idénticos. Los pares de fotones fueron cuidadosamente caracterizados por medio de una tomografía completa del estado cuántico que muestra la gran fidelidad con un estado NOON perfecto. Después de filtrar la producción de la fuente de fotones por medio de un novedoso filtro basado en el esquema “interaction-free measurement”, una medida de correlación cruzada demostró su potencial como fuente de fotones individuales anunciados de banda estrecha que resulta necesaria, por ejemplo, en la información cuántica. Para aplicar estos estados en un esquema de metrología cuántica y demostrar la ventaja metrológica, elegimos un magnetómetro atómico como sistema modelo. El montaje del magnetómetro delimitado por el límite cuántico estándar se basa en el efecto Faraday en un vapor de átomos de rubidio calientes. Se podía demostrar que el comportamiento de ambos estados cuánticos es superior en la aplicación con el magnetómetro que cualquier estado clásico, es decir, que superan el SQL. En el caso de los estados NOON, este es el primer uso de la coherencia multifotónica en un experimento atómico. Además de las aplicaciones en la metrología cuántica, las técnicas presentadas de generación de luz cuántica y filtración también son directamente aplicables a las tareas de información cuántica, en especial al uso en las memorias cuánticas.
15
Gniesmer, Jan [Verfasser]. „Advanced techniques for squeezed-light-enhanced gravitational-wave detection / Jan Gniesmer“. Hannover : Gottfried Wilhelm Leibniz Universität Hannover, 2019. http://d-nb.info/118931147X/34.
16
Smyth, William Samuel. „Non-classical atom field interactions in quantum optics“. Thesis, Queen's University Belfast, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318736.
17
Buchler, Benjamin Caird. „Electro-optic control of quantum measurements“. View thesis entry in Australian Digital Theses Program, 2001. http://thesis.anu.edu.au/public/adt-ANU20020527.131758/index.html.
18
Lucivero, Vito Giovanni. „Quantum metrology with high-density atomic vapors and squeezed states of light“. Doctoral thesis, Universitat Politècnica de Catalunya, 2016. http://hdl.handle.net/10803/403962.
Annotation:
Nowadays there is a considerable progress in optical magnetometry and spin noise spectroscopy, which use magnetically-sensitive atomic ensembles and optical read-out, approaching the limits set by quantum mechanics. In recent years optical magnetometers have become the most sensitive instruments for measuring low-frequency magnetic fields, achieving sub-femtotesla sensitivity and surpassing the competitive superconducting quantum interference devices (SQUIDs), and have found applications in biomedicine, geophysics, space science as well as in tests of fundamental physics. Another emerging technique is spin noise spectroscopy (SNS), which allows one to determine physical properties of an unperturbed spin system from its power noise spectrum. In the last decade technological advances like real-time spectrum analyzers and shot-noise-limited detectors have allowed improvements in the sensitivity of spin noise detection leading to a broad range of applications in both atomic and solid state physics.
The main goal of this thesis is to address a major outstanding question: whether squeezed light can improve the sensitivity of atomic sensors under optimal sensitivity conditions, typically in a high-density regime due to the statistical advantage of using more atoms.
Firstly, we describe the design, construction and characterization of a new versatile experimental apparatus for the study of squeezed-light atomic spectroscopy within a high-density regime (n=¿10¿^12 ¿cm¿^(-3)) and low-noise (¿pT/vHz) magnetic environment. The new experimental system is combined with an existing source of polarization squeezed light based on spontaneous parametric down conversion (SPDC) in a nonlinear crystal, which is the active medium of an optical parametric oscillator.
Secondly, we report the first experimental demonstration of quantum-enhanced spin noise spectroscopy of natural abundance Rb via polarization squeezing of the probe beam. We found that input squeezing of 3.0 dB improves the signal-to-noise ratio by 1.5 dB to 2.6 dB over the combined (power¿number density) ranges (0.5 mW to 4.0 mW) ¿ (1.5 ׿10¿^12 ¿cm¿^(-3) to 1.3 ׿10¿^13 ¿cm¿^(-3)), covering the ranges used in optimized spin noise spectroscopy experiments. We also show that squeezing improves the trade-off between statistical sensitivity and broadening effects.
Next, we introduce a novel theoretical model by defining a standard quantum limit (SQL) for optically-detected noise spectroscopy, identified as a bound to the covariance of the parameters estimated by fitting power noise spectra. We test the model for spin noise spectroscopy of natural abundance Rb and we demonstrate experimental performance of SNS at the SQL for a coherent probe and below the SQL for a polarization squeezed probe.
Finally, we report an optical magnetometer based on amplitude modulated optical rotation (AMOR), using a 85Rb vapor cell, that achieves room temperature sensitivity of 70 fT/vHz at 7.6 µT and we demonstrate its photon shot-noise-limited (SNL) behaviour from 5 µT to 75 µT. While no quantum resources of light were used in this second experiment, the combination of best sensitivity, in the class of room-temperature scalarHoy en día existe un considerable progreso en la magnetometría óptica y espectroscopía de ruido de espin, que utilizan conjuntos atómicos magnéticamente sensibles y lectura óptica, acercándose a los límites establecidos por la mecánica cuántica. En los últimos años los magnetómetros ópticos se han convertido en los instrumentos más sensibles para medir los campos magnéticos de baja frecuencia, logrando sensibilidad de sub-femtotesla y superando dispositivos como los superconductores de interferencia cuántica (SQUID), y han encontrado aplicaciones en biomedicina, geofísica, ciencia espacial, así como en varias pruebas de física fundamental. Otra técnica emergente es la espectroscopía de ruido de espin (SNS), que permite determinar las propiedades físicas de un sistema de espin sin perturbarlo por medio de su espectro de potencia de ruido. En la última década, los avances tecnológicos como analizadores de espectro en tiempo real y detectores limitados por el ruido de disparo de fotón han permitido mejoras en la sensibilidad de detección de ruido de spin que conduce a una amplia gama de aplicaciones tanto en la física del estado sólido como en la física atómica. El objetivo principal de esta tesis es responder a una cuestión pendiente e importante: si la "luz comprimida" puede mejorar la sensibilidad de los sensores atómicos en condiciones óptimas para la sensibilidad, típicamente en un régimen de alta densidad debido a la ventaja estadística de utilizar más átomos. En primer lugar, se describe el diseño, construcción y caracterización de un nuevo aparato experimental versátil para el estudio de la espectroscopia atómica con luz comprimida dentro de un régimen de alta densidad (n=¿10¿^12 ¿cm¿^(-3)) y bajo nivel de ruido magnético (¿pT/vHz). El nuevo sistema experimental se combina con una fuente existente de luz comprimida en polarización, basado en el proceso de conversión paramétrica espontánea descendente (SPDC) en un cristal no lineal, que es el medio activo de un oscilador paramétrico óptico. En segundo lugar, se presenta la primera demostración experimental de espectroscopía de espin de Rubidio, en abundancia natural, mejorada a través de la compresión en polarización de la luz de prueba. Se encontró que la entrada de 3.0 dB de luz comprimida mejora la relación señal-ruido de 1.5 dB a 2.6 dB en el intervalo combinado (potencia óptica)¿(densidad atómica) de (0.5 mW to 4.0 mW) ¿ (1.5׿10¿^12 ¿cm¿^(-3) to 1.3׿10¿^13 ¿cm¿^(-3)), que cubre rangos utilizados en los experimentos optimizados de espectroscopía de ruido de espin. También mostramos que la luz comprimida mejora el equilibrio entre la sensibilidad estadística y efectos de ampliación de la resonancia. A continuación, se introduce un nuevo modelo teórico con la definición de un límite cuántico estándar (SQL) para la espectroscopía de ruido detectado ópticamente, identificado como un límite a la covarianza de los parámetros estimados mediante el ajuste de los espectros de potencia de ruido. Probamos el modelo para la espectroscopia de ruido de espin en abundancia natural de rubidio y demostramos el rendimiento experimental de la espectroscopia de ruido al límite cuántico estándar para una haz coherente y por debajo del SQL para una haz de luz comprimida en polarización. Por último, se presenta un magnetómetro óptico basado en rotación óptica modulada en amplitud (AMOR), utilizando una celda de vapor de 85Rb, que logra sensibilidad a la temperatura ambiente de 70 fT/vHz a 7.6 µT y demostramos su limite de ruido de disparo de fotón (SNL) en el intervalo de 5 µT a 75 µT. Si bien no se utilizaron recursos cuánticos de la luz en este segundo experimento, la combinación de la mejor sensibilidad, en la clase de los magnetómetros escalares de temperatura ambiente, y con operación al limite de ruido de disparo hace que el sistema sea un candidato prometedor para la aplicación de luz comprimida a un magnetómetro óptico optimizado con mejor sensibilidad en la clase
19
Schönbeck, Axel [Verfasser], und Roman [Akademischer Betreuer] Schnabel. „Compact squeezed-light source at 1550 nm / Axel Schönbeck ; Betreuer: Roman Schnabel“. Hamburg : Staats- und Universitätsbibliothek Hamburg, 2018. http://d-nb.info/1165774429/34.
20
Zhao, Shiyuan. „Noise, Dynamics and Squeezed Light in Quantum Dot and Interband Cascade Lasers“. Electronic Thesis or Diss., Institut polytechnique de Paris, 2023. http://www.theses.fr/2023IPPAT044.
Annotation:
Les lasers à semiconducteurs sont devenus omniprésents aussi bien dans la recherche scientifique que dans les applications en ingénierie, et leur miniaturisation a fait d'importants progrès depuis leur première démonstration en 1960. Deux avancées majeures dans ce domaine incluent les lasers à boîtes quantiques (QD), qui opèrent dans la plage de longueurs d'onde proche de l'infrarouge, et les lasers à cascade interbande (ICL), conçus pour une utilisation dans le moyen infrarouge. Dans le paysage actuel de l'optoélectronique, les circuits intégrés photoniques (CIP) jouent un rôle essentiel et étendu. Ils offrent une évolutivité inégalée, un poids réduit, une rentabilité et une efficacité énergétique en permettant la fabrication de systèmes optiques complets à l'aide de blocs de construction polyvalents intégrés sur une seule puce. Dans ce contexte, la croissance épitaxiale directe de matériaux III-V sur du silicium offre des perspectives prometteuses en tant qu'approche convaincante pour le développement de sources laser cohérentes. Les lasers à boîtes quantiques, avec leur confinement ultime des porteurs en trois dimensions, leur grande stabilité thermique et leur tolérance robuste aux défauts épitaxiaux, sont des candidats prometteurs pour servir de sources laser sur puce. De plus, les ICL sont également bien adaptés à l'intégration dans le silicium, ce qui en fait des candidats idéaux pour les systèmes compacts de détection chimique. Les considérations liées au bruit sont en effet primordiales lorsqu'il s'agit d'évaluer la qualité et la fiabilité des cette technologie. Atteindre la limite du bruit de grenaille et la largeur de raie de Schawlow-Townes a longtemps été reconnu comme des étapes significatives. Pour résoudre les problèmes de bruit, toute une gamme de techniques de réduction du bruit a été explorée, allant de la rétroaction optique passive dans une cavité externe aux mécanismes actifs de rétroaction électronique visant à compenser les fluctuations du courant d'injection. Cependant, bien que les systèmes de rétroaction puissent atténuer le bruit du laser, ils peuvent également introduire des dynamiques non linéaires plus complexes, donnant lieu à des phénomènes tels que l'oscillation périodique, l'oscillation en créneaux et le chaos. La première partie de cette thèse porte sur une investigation approfondie du bruit et de la dynamique dans deux types de lasers distincts. On constate que les lasers à boîtes quantiques présentent un degré élevé de robustesse lorsqu'ils sont exposés à des réflexions optiques parasites, mais manifestent une sensibilité accrue à la rétroaction optoélectronique. En revanche, les ICL affichent une gamme de comportements dynamiques lorsqu'ils sont soumis à une rétroaction optique. De plus, les récents progrès dans les circuits de pompage à faible bruit pour les lasers ont conduit à la génération de lumière comprimée en amplitude. Il s'agit d'une transition du bruit classique au bruit quantique, ouvrant de nouvelles possibilités dans le domaine de la technologie laser et de l'optique quantique. La deuxième partie de cette thèse se penche sur le phénomène de la compression en amplitude à la fois dans les lasers à boîtes quantiques et dans les ICL. Les résultats indiquent que les deux types de lasers peuvent présenter une large bande passante de compression et un niveau significatif de compression. Toutes ces conclusions dans cette étude contribuent à une compréhension plus profonde des caractéristiques des lasers à boîtes quantiques et des ICL, jetant les bases du développement de sources émettrices classiques et quantiques de haute performance sur des CIP à l'avenirSemiconductor lasers have become ubiquitous in both scientific research and engineering applications, and their miniaturization has made significant strides since their initial demonstration in 1960. Two prominent advancements in this domain include quantum dot (QD) lasers, which operate in the near-infrared wavelength range, and interband cascade lasers (ICLs), designed for mid-infrared operation. Two prominent advancements in this domain include quantum dot (QD) lasers, which operate in the near-infrared wavelength range, and interband cascade lasers (ICLs), designed for mid-infrared operation. In the current landscape of optoelectronics, photonic integrated circuits (PICs) play a pivotal and far-reaching role. They offer unmatched scalability, reduced weight, cost-effectiveness, and energy efficiency by enabling the fabrication of complete optical systems using versatile building blocks seamlessly integrated onto a single chip. In this context, the direct epitaxial growth of III-V materials on silicon holds promise as a compelling approach for the development of coherent laser sources. QD lasers with their ultimate three-dimensional carrier confinement, high thermal stability, and robust tolerance for epitaxial defects are promising candidates for serving as on-chip laser sources. Additionally, ICLs are also well-suited for integration into silicon, making them ideal for compact chemical sensing systems. Noise considerations are indeed paramount when it comes to assessing the quality and reliability of technologies. Achieving the shot noise limit and the Schawlow-Townes linewidth has long been recognized as significant milestones. To tackle noise issues, a range of noise reduction techniques has been explored, encompassing passive optical feedback within an external cavity and active electronic feedback mechanisms to compensate for injection current fluctuations. However, while feedback systems can mitigate laser noise, they can also introduce more intricate nonlinear dynamics, giving rise to phenomena like periodic oscillation, square-wave oscillation, and chaos. The first part of this thesis involves an in-depth investigation into noise and dynamics in two distinct laser types. QD lasers are found to exhibit a high degree of robustness when exposed to parasitic optical reflections but manifest increased sensitivity to optoelectronic feedback. Conversely, ICLs display a spectrum of dynamic behaviours when subjected to optical feedback. Furthermore, recent advancements in low-noise pumping circuits for lasers have led to the generation of amplitude-squeezed light. This represents a transition from classical noise to quantum noise, opening up new possibilities in the field of laser technology and quantum optics. The second part of this thesis delves into the phenomenon of amplitude squeezing in both QD lasers and ICLs. The findings indicate that both types of lasers can exhibit broadband squeezing bandwidth and a significant level of squeezing. All these outcomes in this study contribute to a deeper comprehension of the characteristics of QD lasers and ICLs, laying the groundwork for the development of high-performance classical and quantum emitters on PICs in the future
21
Khalaidovski, Aleksandr [Verfasser]. „Beyond the quantum limit : a squeezed-light laser in GEO 600 / Aleksandr Khalaidovski“. Hannover : Technische Informationsbibliothek und Universitätsbibliothek Hannover (TIB), 2012. http://d-nb.info/1021439045/34.
22
SEQUINO, VALERIA. „Development of a squeezed light source for the gravitational wave detector Advanced Virgo“. Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2015. http://hdl.handle.net/2108/201977.
23
Tesfamariam, Alem Mebrahtu. „Fluctuations in quantum optical systems from Bose-Einstein condensates to squeezed states of light /“. [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=983242283.
24
Lemieux, Samuel. „Tailoring the Modal Structure of Bright Squeezed Vacuum States of Light via Selective Amplification“. Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/34920.
Annotation:
The bright squeezed vacuum state of light is a macroscopic nonclassical state found at the output of a strongly pumped unseeded travelling-wave optical parametric amplifier. It has been applied to quantum imaging, quantum communication, and phase supersensitivity, to name a few. Bright squeezed states are in general highly multimode, while most applications require a single mode. We separated two nonlinear crystals in the direction of propagation of the pump in order to narrow the angular spectrum down to a nearly-single angular mode. We observed noise reduction in the photon number difference between the two down-converted channels, which constitutes of proof of nonclassicality. By introducing a dispersive medium between the two nonlinear crystals, we were able to tailor the frequency spectrum of bright squeezed vacuum and to dramatically reduce the number of frequency modes down to 1.82 ± 0.02, bringing us closer to truly single-mode bright squeezed vacuum.
25
Kleybolte, Lisa Marie [Verfasser], und Roman [Akademischer Betreuer] Schnabel. „Sensitivity Enhancement of Optomechanical Measurements using Squeezed Light / Lisa Marie Kleybolte ; Betreuer: Roman Schnabel“. Hamburg : Staats- und Universitätsbibliothek Hamburg, 2019. http://d-nb.info/1197801464/34.
26
Zander, Jascha [Verfasser]. „Squeezed and Entangled Light: From Foundations of Quantum Mechanics to Quantum Sensing / Jascha Zander“. Hamburg : Staats- und Universitätsbibliothek Hamburg Carl von Ossietzky, 2021. http://d-nb.info/1240386389/34.
27
Crouch, David Dale Thorne Kip S. Thorne Kip S. „A theoretical study of the generation of squeezed-state light via degenerate parametric amplification /“. Diss., Pasadena, Calif. : California Institute of Technology, 1988. http://resolver.caltech.edu/CaltechETD:etd-11022007-131309.
28
Buchler, Benjamin Caird, und ben buchler@anu edu au. „Electro-optic control of quantum measurements“. The Australian National University. Faculty of Science, 2002. http://thesis.anu.edu.au./public/adt-ANU20020527.131758.
Annotation:
The performance of optical measurement systems is ultimately limited by the
quantum nature of light. In this thesis, two techniques for circumventing the
standard quantum measurement limits are modelled and tested experimentally.
These techniques are electro-optic control and the use of squeezed light.
An optical parametric amplifier is used to generate squeezing at
1064nm. The parametric amplifier is pumped by the output of a second
harmonic generation cavity, which in turn is pumped by a Nd:YAG laser.
By using various frequency locking techniques, the quadrature phase of
the squeezing is stabilised, therefore making our squeezed source
suitable for long term measurements. The best recorded squeezing is
5.5dB (or 70\%) below the standard quantum limit. The stability of
our experiment makes it possible to perform a time domain measurement
of photocurrent correlations due to squeezing. This technique allows
direct visualisation of the quantum correlations caused by squeezed
light.
On the road to developing our squeezed source, methods of frequency
locking optical cavities are investigated. In particular, the tilt
locking method is tested on the second harmonic generation cavity
used in the squeezing experiment. The standard method for locking
this cavity involves the use of modulation sidebands, therefore leading to a
noisy second harmonic wave. The modulation free tilt-locking method,
which is based on spatial mode interference, is shown to be a
reliable alternative.
In some cases, electro-optic control may be used to suppress quantum
measurement noise. Electro-optic feedback is investigated as a method
for suppressing radiation pressure noise in an optical cavity.
Modelling shows that the `squashed' light inside a feedback loop can
reduce radiation pressure noise by a factor of two below the standard
quantum limit. This result in then applied to a thermal noise
detection system. The reduction in radiation pressure noise is shown
to give improved thermal noise sensitivity, therefore proving that
the modified noise properties of light inside a feedback loop can be
used to reduce quantum measurement noise.
Another method of electro-optic control is electro-optic feedforward.
This is also investigated as a technique for manipulating quantum
measurements. It is used to achieve noiseless amplification of a
phase quadrature signal. The results clearly show that a feedforward
loop is a phase sensitive amplifier that breaks the quantum limit for
phase insensitive amplification. This experiment is the first
demonstration of noiseless phase quadrature amplification.
Finally, feedforward is explored as a tool for improving the
performance of quantum nondemolition measurements. Modelling shows
that feedforward is an effective method of increasing signal transfer
efficiency. Feedforward is also shown to work well in conjunction with
meter squeezing. Together, meter squeezing and feedforward provide a
comprehensive quantum nondemolition enhancement package. Using the
squeezed light from our optical parametric amplifier, an experimental
demonstration of the enhancement scheme is shown to achieve record
signal transfer efficiency of $T_{s}+T_{m}=1.81$.
29
Finelli, Stefano. „Realizzazione di un sistema di stabilizzazione per laser a stato solido, per la generazione di luce squeezed in esperimenti di interferometria“. Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/8296/.
Annotation:
Con questo lavoro di tesi si affrontano i primi accorgimenti sperimentali necessari alla realizzazione di un esperimento di ottica quantistica. L'attività svolta consiste nell'ottimizzazione dei parametri di un PLL (Phase-Locked Loop) che mantiene due laser agganciati in frequenza, e nella misura del rumore di fase presente nell'aggancio. Questa stabilizzazione costituisce il primo passo per la generazione di luce squeezed, associata a particolari stati del campo elettromagnetico. Grazie a quest'ultima, è possibile migliorare la sensibilità raggiungibile in esperimenti di interferometria di precisione, quali ad esempio quelli per la ricerca di onde gravitazionali. L'iniezione di luce squeezed costituirà infatti parte del prossimo upgrade dell'interferometro di Virgo.
30
Mehmet, Moritz [Verfasser]. „Squeezed light at 1064 nm and 1550 nm with a nonclassical noise suppression beyond 10 dB / Moritz Mehmet“. Hannover : Technische Informationsbibliothek und Universitätsbibliothek Hannover (TIB), 2012. http://d-nb.info/1022760688/34.
31
Schreiber, Emil [Verfasser]. „Gravitational-wave detection beyond the quantum shot-noise limit : the integration of squeezed light in GEO 600 / Emil Schreiber“. Hannover : Gottfried Wilhelm Leibniz Universität Hannover, 2018. http://d-nb.info/1172414548/34.
32
KHAN, IMRAN. „Squeezed states of light generation for Short Noise limited Interferometric measurements in the next generation of Gravitational Waves Detectors“. Doctoral thesis, Gran Sasso Science Institute, 2019. http://hdl.handle.net/20.500.12571/10001.
Annotation:
The advanced generation of ground based Gravitational Waves (GW) detectors are mainly limited by Quantum Noise (QN) in almost the entire detection bandwidth i.e., 10 Hz - 10 kHz. The coherent vacuum field entering through the output port of the interferometer causes the phase and intensity fluctuations of the circulating light field inside the detector and as a result, the interferometeric measurements are shot noise limited at high frequencies (above 100 Hz up to 10 kHz) and radiation pressure noise limited at low frequencies (below 100 Hz) of the detection bandwidth. The impact of shot noise in GW detectors appears as fluctuating intensity of the output laser light field and radiation pressure noise impinge fluctuating momentum on the test masses, thus displacing the test masses around their equilibrium positions. These noise components obey the Heisenberg uncertainty principle. Since the very basic principle of GWs detection involves the test masses to be quieter than the signal (GW signal) of interest, therefore all noise sources influencing the suspended test masses have to be below the GWs signal magnitude.
Caves first proposed the concept of squeezed states of light in GW detectors, to improve the QN limited strain sensitivity. The idea is to replace the coherent vacuum field by the injection of phase squeezed vacuum field into the interferometer’s output port, that improves the shot noise limited interferometric measurements by reducing variance in the phase quadrature on the cost of increased variance in the amplitude quadrature of the vacuum field. Squeezed states of light are generated in degenerate Optical Parametric Amplification (OPA) process in our experiment, where the second order nonlinearity of a nonlinear crystal is exploited.
At European Gravitational Observatory (EGO), where the Advanced Virgo (AdV) detector is situated, we have laboratory facility to produce frequency independent squeezed states of light for input laser field at 1064 nm as a test facility for future frequency dependent squeezed states of light generation experiment. The aim of the experiment is to produce measured squeezing level 13 dB. Part of my thesis work concerned the experimental demonstration of squeezed states of light generation and we achieved more than 4 dB of measured squeezing in the Radio Frequency (RF) bandwidth for input laser field at 1064 nm.
Along with the squeezing activity, I demonstrated experimentally the single pass Second Harmonic Generation (SHG) in Periodically Poled Potassium Titanyl Phosphate (PPKTP) and Periodically Poled Lithium Niobate (PPLN) nonlinear crystals, that can be used as squeezing pump beam and auxiliary lasers for AdV. In particular, the SHG in PPLN crystal is performed using a fibered amplified Infrared (IR) laser source at 1064 nm, that eliminates the need for dedicated IR laser unit. All these experimental activities contribute towards the ongoing R&D activities in optical systems at AdV.
33
Sansavini, Francesca. „Quantum information protocols in complex entangled networks“. Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/18512/.
Annotation:
Quantum entangled networks represent essential tools for Quantum Communication, i.e. the exchange of Quantum Information between parties. This work consists in the theoretical study of continuous variables (CV) entangled networks - which can be deterministically generated via multimode squeezed light - with complex topology. In particular we investigate CV complex quantum networks properties for quantum communication protocols. We focused on the role played by the topology in the implementation and the optimization of given characteristics of our entangled resource that are useful for a specific quantum communication task, i.e. the creation of an entanglement link between two arbitrary nodes of the resource we are provided with. We implemented an analytical procedure for the generation of entangled complex networks, their optimization and their manipulation via global linear optics operations. We also developed a numerical procedure, based on an evolutionary algorithm, for manipulating entanglement connections via local linear optics operations. Finally, we analyzed the re-shaping of our entangled resource via homodyne measurements.
34
Otterpohl, Alexander [Verfasser], Christoph [Akademischer Betreuer] Marquardt, Christoph [Gutachter] Marquardt und Zanthier Joachim [Gutachter] von. „Squeezed vacuum states of light from a crystalline whispering gallery mode resonator / Alexander Otterpohl ; Gutachter: Christoph Marquardt, Joachim von Zanthier ; Betreuer: Christoph Marquardt“. Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2020. http://d-nb.info/1223175278/34.
35
Burks, Sidney. „Towards A Quantum Memory For Non-Classical Light With Cold Atomic Ensembles“. Phd thesis, Université Pierre et Marie Curie - Paris VI, 2010. http://tel.archives-ouvertes.fr/tel-00699270.
Annotation:
Une mémoire quantique réversible permettant de stocker et relire de l'information quantique est une composante majeure dans la mise en œuvre de nombreux protocoles d'information quantique. Comme la lumière est un porteur de l'information quantique fiable sur des longues distances, et comme les atomes offrent la possibilité d'obtenir de longues durées de stockage, le recherche actuelle sur la création d'une mémoire quantique se concentre sur la transfert des fluctuations quantiques de la lumière sur des cohérences atomiques. Le travail réalisé durant cette thèse porte sur le développement d'une mémoire quantique pour la lumière comprimée, utilisant un ensemble d'atomes froids de Césium stock'es dans un piege magnéto-optique. Nos deux principaux objectifs étaient le développement d'une source de lumière non-classique, et le développement d'un milieu atomique pour le stockage de celle-ci. Tout d'abord, nous commençons par présenter la construction d'un oscillateur paramétrique optique qui utilise un cristal non-linéaire de PPKTP. Cet OPO fonctionne comme source d'états de vide comprime résonant avec la raie D2 du Césium. Nous caractérisons ces états grâce à une reconstruction par tomographie quantique, en utilisant une approche de vraisemblance maximale. Ensuite, nous examinons une nouvelle expérience qui nous permet d'utiliser comme milieu de stockage des atomes froids de Césium dans un piège magneto-optique récemment développé. Car cette expérience exige l'utilisation de nouveaux outils et techniques, nous discutons le développement de ceux-ci, et comment ils ont contribue à notre progression vers le stockage des états quantiques dans nos atomes des Césium, et finalement vers l'intrication de deux ensembles atomiques.
36
Hamley, Christopher David. „Spin-nematic squeezing in a spin-1 Bose-Einstein condensate“. Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/47523.
Annotation:
The primary study of this thesis is spin-nematic squeezing in a spin-1 condensate.
The measurement of spin-nematic squeezing builds on the success of previous experiments of spin-mixing together with advances in low noise atom counting.
The major contributions of this thesis are linking theoretical models to experimental results and the development of the intuition and tools to address the squeezed subspaces.
Understanding how spin-nematic squeezing is generated and how to measure it has required a review of several theoretical models of spin-mixing as well as extending these existing models. This extension reveals that the squeezing is between quadratures of a spin moment and a nematic (quadrapole) moment in abstract subspaces of the SU(3) symmetry group of the spin-1 system.
The identification of the subspaces within the SU(3) symmetry allowed the development of techniques using RF and microwave oscillating magnetic fields to manipulate the phase space in order to measure the spin-nematic squeezing. Spin-mixing from a classically meta-stable state, the phase space manipulation, and low noise atom counting form the core of the experiment to measure spin-nematic squeezing. Spin-nematic squeezing is also compared to its quantum optics analogue, two-mode squeezing generated by four-wave mixing.
The other experimental study in this thesis is performing spin-dependent photo-association spectroscopy. Spin-mixing is known to depend on the difference of the strengths of the scattering channels of the atoms. Optical Feshbach resonances have been shown to be able to alter these scattering lengths but with prohibitive losses of atoms near the resonance. The possibility of using multiple nearby resonances from different scattering channels has been proposed to overcome this limitation. However there was no spectroscopy in the literature which analyzes for the different scattering channels of atoms for the same initial states. Through analysis of the initial atomic states, this thesis studies how the spin state of the atoms affects what photo-association resonances are available to the colliding atoms based on their scattering channel and how this affects the optical Feshbach resonances. From this analysis a prediction is made for the extent of alteration of spin-mixing achievable as well as the impact on the atom loss rate.
37
Fedortchenko, Sergueï. „The ultrastrong coupling regime as a resource for the generation of nonclassical states of light“. Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCC279/document.
Annotation:
Depuis l’avènement de la mécanique quantique, l’étude des interactions lumière-matière à l’échelle quantique s’est énormément développée en tant que domaine de recherche. Par exemple, grâce à des prédictions théoriques surprenantes, des interactions d’une force sans précédant ont été démontrées entre de la matière et des radiations terahertz et microonde. Ces résultats correspondent à un régime dit de couplage ultrafort, atteint lorsque l’énergie d’interaction devient comparable aux énergies propres de la lumière et de la matière lorsque celles-ci n’interagissent pas. Dans ce régime, des propriétés intrigantes peuvent subsister telles que la présence de photons même lors qu’aucune énergie n’est fournie au système. Cependant, ces photons ne peuvent, a priori, être émis du système vers l’extérieur de manière à pouvoir être mesurés et par conséquent démontrer ces propriétés.Dans cette thèse, nous avons étudié ces propriétés intrigantes et proposé plusieurs moyens permettant d’y accéder expérimentalement. Nous nous sommes appuyés sur plusieurs plate-formes physiques qui sont de bon candidats pour ces études, et pour chacun de ces systèmes nous avons mis au point un modèle mettant en évidence ces propriétés d’une manière ou d’une autre. De cette façon, nous avons exploré le lien entre le régime de couplage ultrafort et la génération d’états non-classiques de la lumière. En outre, dans une étude plus ouverte nous avons montré que les interactions lumière- matière dans l’une de ces plate-formes peuvent être utilisés pour concevoir des protocols de communication quantique. En plus de montrer un intérêt fondamental, nos résultats s’inscrivent dans une optique de développement d’applications pour les technologies quantiques en utilisant différents systèmes expérimentaux disponibles actuellementSince the advent of quantum mechanics, the study of light-matter interactions at thequantum level has been greatly developed as a research field. For instance, surprisingtheoretical predictions gave rise to experiments with unprecedented interactionstrengths between matter, and terahertz and microwave radiations. These results correspondto the so-called ultrastrong coupling regime, that is reached when the interactionenergy becomes comparable to the typical energies of the light and matter when they arenot interacting. In this regime, intriguing properties can be found such as the presenceof photons even when no energy is given to the system. However, these photons cannot,a priori, be emitted from the system to the outside world in order to be measured andtherefore demonstrate these properties. In this thesis, we studied these intriguing properties and proposed several means toaccess them experimentally. We relied on several physical platforms which are goodcandidates for such studies, and for each one of these systems we devised a model thatcan evidence these properties one way or another. By doing so, we explored the linkbetween the ultrastrong coupling regime and the generation of nonclassical states oflight. Additionally, as an outlook we showed that the light-matter interactions in oneof these platforms could be used to design quantum communication protocols. On topof showing fundamental interest, our results fit in the line of developing applications forquantum technologies using different experimentally available systems
38
Fedrici, Bruno. „Solutions évolutives pour les réseaux de communication quantique“. Thesis, Université Côte d'Azur (ComUE), 2017. http://www.theses.fr/2017AZUR4117/document.
Annotation:
Le déploiement de réseaux de communication quantique représente un défi auquel cette thèse apporte des solutions originales. Deux dispositifs très performants sont construits uniquement autour de composants standards de l'optique intégrée et des télécommunications optiques. Le premier correspond à un schéma de synchronisation tout optique sur longue distance à très haute cadence et de précision inégalée pour la communication sécurisée par cryptographie quantique. Le montage expérimental repose sur une configuration de relais quantique mettant en œuvre deux sources indépendantes de paires de photons intriqués dont il faut synchroniser les temps d'émissions. L’idée principale s’appuie sur l’utilisation d’un unique laser télécom picoseconde cadencé à 2.5 GHz afin de générer l’horloge et de pouvoir la distribuer efficacement aux deux sources. Nous démontrons la synchronisation de notre lien relais pour une distance effective séparant les sources de plus de 100 km. Le second dispositif correspond quant à lui à la réalisation d'une expérience de compression à une longueur d'onde des télécommunications réalisée, pour la première fois, de manière entièrement guidée. La lumière comprimée étant une ressource fondamentale dans bon nombre de protocoles d'information quantique, la réalisation de systèmes expérimentaux facilement reconfigurables et compatibles avec les réseaux télécoms fibrés existants représente une étape cruciale en vue du déploiement de dispositifs de communication quantique en régime de variables continues. Enfin, un traitement quantique des effets de gigue temporelle dans les détecteurs de photons 0N/0FF est proposé. Malgré l'importance des systèmes de détection dans les technologies quantiques photoniques émergentes, aucune modélisation quantique de leurs effets de gigue temporelle n'avait été, à notre connaissance, développé jusqu'à présentThis thesis presents solutions to the challenges of developing quantum communication networks. Two powerful experimental devices have been set up relying only on standard telecom and integrated optical components. The first device corresponds to an all-optical synchronization scheme allowing, with an unprecedented accuracy, quantum key distribution at a high rate over long distances. The experimental scheme relies on two independent entangled photon pair sources that have to be synchronized in their emission time. Our approach is based on using a 2.5 GHz picosecond telecom laser as a master clock to efficiently synchronize the different sources. We demonstrate the synchronization for an effective distance of 100 km between sources. With our second device, we perform a squeezing experiment at telecom wavelengths and this for the first time in a fully guided-wave approach. Squeezed light being a fundamental resource for several quantum information protocols, developing plug-and-play experimental devices that are compatible with already existing telecom fiber networks is of first interest in the perspective of future quantum networks. Finally, we propose a quantum description of timing jitter effects in 0N/0FF detectors. Despite the importance of detection systems in emerging photonic quantum technologies, no quantum description of their timing jitter effects has been proposed so far
39
Mondain, François. „Source intégrée de lumière comprimée aux longueurs d’ondes des télécommunications“. Thesis, Université Côte d'Azur, 2020. http://www.theses.fr/2020COAZ4013.
Annotation:
Les récents progrès de la physique quantique en matière de manipulations d'objets quantiques individuels et/ou collectifs promettent une révolution dans les domaines de la communication, de la métrologie, de l'informatique et de la simulation. Plus spécifiquement, l'avènement des nouvelles technologies quantiques repose sur la génération, la manipulation et le contrôle d'états quantiques tels que l'intrication. Découverte il y a plus de 30 ans, la lumière comprimée s'est imposée comme un outil de choix pour la mise en œuvre des technologies quantiques, mais son utilisation souffre encore aujourd'hui d'un manque crucial de compacité, freinant ainsi la croissance de certaines réalisations en photonique quantique.Pour pallier ce problème, nous avons développé une plateforme photonique compacte de génération et de détection de lumière comprimée aux longueurs d’ondes des télécommunications. Elle repose sur le mariage entre les composants à fibre optique standards à 1550 nm et de l'optique intégrée sur niobate de lithium (LiNbO3), permettant d'obtenir un montage compact, facilement reconfigurable sans qu'aucun alignement ne soit nécessaire (plug-and-play). Grâce à cette approche, nous avons pu mesurer jusqu’à -2 dB de compression pour une puissance de pompe continue de 40 mW, ouvrant ainsi la voie vers la réalisation de systèmes compacts de variables continues en dehors du cadre des laboratoires.Afin de mieux comprendre les limites de notre système expérimental, nous nous sommes également intéressés aux propriétés photoréfractives du niobate de lithium, c'est-à-dire à la variation de son indice optique en fonction de l'intensité lumineuse qui le traverse. En régime de variables continues, là où les puissances optiques peuvent être relativement élevées, ces effets peuvent durablement affecter le fonctionnement des circuits photoniques intégrés sur LiNbO3. Pour cette raison, une étude précise de la photoréfraction a également été accomplie afin d’optimiser la génération et la détection de la lumière comprimée sur puce LiNbO3Recent progress in quantum physics predicts a future revolution in the fields of communication, sensing, computing and simulation which rely on our hability to generate and control quantum states such as entanglement. Discovered more than thirty years ago, squeezed light has rapidly became an important tool for the implementation of quantum technologies, but its use still suffers from a lack of compactness wich limits the growth of quantum photonics realisations. To tackle this issue, we developpe a compact photonic platform to generate and detect squeezed light at telecom wavelengths. It is build upon an association between off the shelf telecom components and integrated optics on lithium niobate (LiNbO3) allowing a compact, and easy reconfigurable setup, without any alignment (plug-and-play). With this original aprroach, we directly measure up to -2dB shot noise reduction for a CW pump power of 40 mW, opening the way to out-of-the lab continuous variable experimentations.In order to fully understand the limits of our experimental setup, we also investigate the photorefractive properties of the LiNbO3, which means his intensity dependant refractive index. This effect could be a great issue in CV experiments, where high pump powers near visible wavelengths are needed. For this reason, we also study precisely the photorefraction in order to optimise the generation and the detection of squeezed light in integrated lithium niobate photonics circuits
40
Bookjans, Eva M. „Relative number squeezing in a Spin-1 Bose-Einstein condensate“. Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/37148.
Annotation:
The quantum properties of matter waves, in particular quantum correlations and entanglement are an important frontier in atom optics with applications in quantum metrology and quantum information. In this thesis, we report the first observation of sub-Poissonian fluctuations in the magnetization of a spinor 87Rb condensate. The fluctuations in the magnetization are reduced up to 10 dB below the classical shot noise limit. This relative number squeezing is indicative of the predicted pair-correlations in a spinor condensate and lay the foundation for future experiments involving spin-squeezing and entanglement measurements. We have investigated the limits of the imaging techniques used in our lab, absorption and fluorescence imaging, and have developed the capability to measure atoms numbers with an uncertainly < 10 atoms. Condensates as small as ≈ 10 atoms were imaged and the measured fluctuations agree well with the theoretical predictions. Furthermore, we implement a reliable calibration method of our imaging system based on quantum projection noise measurements. We have resolved the individual lattice sites of a standing-wave potential created by a CO2 laser, which has a lattice spacing of 5.3 µm. Using microwaves, we site-selectively address and manipulate the condensate and therefore demonstrate the ability to perturb the lattice condensate of a local level. Interference between condensates in adjacent lattice sites and lattice sites separated by a lattice site are observed.
41
Gouzien, Élie. „Optique quantique multimode pour le traitement de l'information quantique“. Thesis, Université Côte d'Azur (ComUE), 2019. http://www.theses.fr/2019AZUR4110.
Annotation:
Cette thèse étudie l’optique quantique multimode, aussi bien du point de vue de la génération que celui de la détection. Elle s’articule autour de trois volets. Nous étudions la génération de lumière comprimée multimode dans une cavité. Pour cela nous considérons la forme la plus générale de hamiltonien quadratique, permettant entre autres de décrire l’utilisation de plusieurs pompes dans un matériau effectuant du mélange à quatre ondes. Une approche combinant fonctions de Green et décompositions de matrices symplectiques est décrite. Cette théorie générique est appliquée à des cas particuliers. Dans un premier temps, des exemples en basse dimension sont donnés. Ensuite, une configuration d’oscillateur paramétrique optique pompé de manière synchrone (SPOPO) est décrite et étudiée ; les résultats obtenus montrent que ce système a un comportement très différent de celui du SPOPO utilisant une non-linéarité d’ordre 2. Ces travaux ouvrent la voie à la réalisation de peignes de fréquences quantiques avec des micro-résonateurs en anneau gravés sur silicium. Un autre problème examiné est celui de prendre en compte l’information temporelle obtenue lors du clic d’un détecteur de photon unique. Pour cela nous utilisons un formalisme multimodal temporel afin d’expliciter les opérateurs décrivant la mesure. Les principaux défauts des détecteurs réels, dont la gigue temporelle, l’efficacité finie et les coups d’obscurité sont pris en compte. L’utilisation des opérateurs est illustrée par la description d’expériences usuelles de l’optique quantique. Enfin, on montre que la lecture du temps de clic du détecteur permet d’améliorer la qualité de l’état généré par une source de photons annoncés. En troisième partie nous présentons un schéma de génération d’intrication hybride entre variables continues et discrètes, pour laquelle la partie discrète est encodée temporellement. Ce schéma est analysé en détail vis-à-vis de sa résistance aux imperfections expérimentalesThis thesis studies multimode quantum optics, from generation to detection of light. It focuses on three main parts. Multimode squeezed states generation within cavity is studied. More specifically, we take into account general quadratic Hamiltonian, which allows describing experiments involving arbitrary number of modes and pumps within a medium performing four-wave mixing. We describe a generic approach combining Green functions and symplectic matrix decomposition. This general theory is illustrated on specific cases. First, low-dimensional examples are given. Then, a synchronously pumped optical parametric oscillator (SPOPO) is described and studied; it shows a very distinct behavior from that of the SPOPO using second order non-linearity. This work opens way to the realization of quantum frequency combs with ring micro-resonators engraved on silicon. Single-photon detectors are described taking into account temporal degrees of freedom. We give positive-valued measurement operators describing such detectors including realistic imperfections such as timing-jitter, finite efficiency and dark counts. Use of those operators is illustrated on common quantum optics experiments. Finally, we show how time-resolved measurement allows improving the quality of state generated by single-photon heralded source. In the third part we propose a protocol for generating a hybrid state entangling continuous and discrete variables parts, for which the discrete part is time-bin encoded. This scheme is aanalysed in detail with respect to its resilience to experimental imperfections
42
Long, Chu Yuen, und 朱元隆. „Photocurrent Fluctuation of Squeezed Light“. Thesis, 1995. http://ndltd.ncl.edu.tw/handle/93687580299078902483.
Annotation:
碩士國立交通大學
物理研究所
83
Theoretical analyses of the fluctuation properties of photo- current are derived. By the quantum theory of light, the noise reduction due to squeezing is explained as a manifestation of the memory effect of photoelectron counting process. It is found that the more the light is squeezed, the larger the memory effect is. Both photon number squeezing and quadrature squeezing are considered. Several parameters are used to model quantum state of light, especially the squeezed coherent light. The quantitative connection between its photon number/ quadrature variance and its photocurrent noise spectrum is established.
43
Hope, Deborah Maree. „Squeezed-state generation in optical bistability“. Phd thesis, 1993. http://hdl.handle.net/1885/138923.
44
Paramanandam, Joshua. „Quantum stochastic communication with photon-number squeezed light“. 2007. http://hdl.rutgers.edu/1782.2/rucore10001600001.ETD.16755.
45
Vahlbruch, Henning [Verfasser]. „Squeezed light for gravitational wave astronomy / von Henning Vahlbruch“. 2008. http://d-nb.info/993947565/34.
46
Lam, Ping Koy. „Applications of Quantum Electro-Optic Control and Squeezed Light“. Phd thesis, 1998. http://hdl.handle.net/1885/47657.
Annotation:
In this thesis, we report the observations of optical squeezing from second harmonic generation (SHG), optical parametric oscillation (OPO) and optical parametric amplification (OPA). Demonstrations and proposals of applications involving the squeezed light and electro-optic control loops are presented. ¶ ...
47
Xie, Daruo. „Generation of bright broadband-squeezed light and broadband quantum interferometry /“. 2008. http://wwwlib.umi.com/dissertations/fullcit/3289606.
48
Mansell, Georgia L. „Squeezed light sources for current and future interferometric gravitational-wave detectors“. Phd thesis, 2018. http://hdl.handle.net/1885/154249.
Annotation:
The era of gravitational-wave astronomy has begun, with the
detection of 5 confirmed binary black holes and a binary neutron
star coalescence by the Advanced Laser Interferometer
Gravitational- wave Observatory (aLIGO), and later with the
advanced Virgo detector. These detections have already revealed a
wealth of discoveries across the fields of nuclear physics,
general relativity and astrophysics. The work presented in this
thesis is part of the ongoing effort to improve the sensitivity
of ground-based interferometric gravitational-wave detectors.
The sensitivity of aLIGO, and other interferometric detectors, is
broadly limited by quantum noise. Improving on the quantum noise
will increase the astrophysical range of the detectors, and
improve the source parameter estimation. One way to reduce
quantum noise is to inject audio- band squeezed vacuum states
into the detection port. This technique has been demonstrated on
the initial LIGO and GEO600 detectors. A squeezed light source
for aLIGO must meet stringent requirements in terms of optical
loss, phase noise, and scattered light. The squeezer must produce
high levels of audio-band squeezing and operate under vacuum, to
take advantage of the excellent existing isolation systems and to
minimise optical loss. At design sensitivity, squeezed states
whose quantum noise depends on frequency will be required.
We have demonstrated an ultra-stable glass-based squeezed light
source, the first experiment of this kind to operate under
vacuum. The squeezer cavity is constructed quasi-monolithically,
with optics and nonlinear crystal oven optically contacted to a
breadboard base. The cavity is designed to have extremely low
length noise, and to produce high levels of audio-band squeezing.
We have measured 8.6 ± 0.9 dB of squeezing and infer the
generation of 14.2 ± 1.0 dB after accounting for all known
losses. The squeezer has demonstrated record phase noise
performance of 1.3 mradRMS, dominated by sources other than
cavity length noise. This exceeds the phase-noise requirement for
a squeezer for aLIGO. A copy of this squeezer is currently being
installed in a squeezing- ellipse rotation experiment to
demonstrate frequency-dependent squeezing for aLIGO. Lessons
learnt during the construction and operation of the in-vacuum
squeezer have helped inform the design of a frequency-independent
squeezed light source currently being installed at the LIGO
sites.
Future gravitational-wave detectors will continue to use
interferometric techniques, and will be limited by quantum noise
for the foreseeable future. To improve on thermal noise limits
and interferometer power handling, future detectors look to
cryogenic silicon as a test mass material. To take advantage of
the desirable properties of silicon, including low scatter and
absorption, a longer operating wavelength is required. The
proposed LIGO Voyager upgrade has an operating wavelength in the
2 μ m region, with the specific wavelength to be determined.
LIGO Voyager will require a squeezed light source in the 2 μ m
region to reach its design sensitivity.
We present the design, characterisation, and results of the first
squeezed light source in the 2 μ m region. Laser and detector
technologies at 2 μ m are less developed than their 1064 nm
counterparts, causing significant technical challenges. We have
measured 4.0 ± 0.2 dB of squeez- ing at 1984 nm, limited by loss
due to detector quantum efficiency. Accounting for known losses
in the system, we infer the generation of 10 dB of squeezing.
This is an important demonstra- tion of quantum noise reduction
for future detectors, and a pathfinder technology for the design
choices of LIGO Voyager. So far we have found no reason why a 2
μ m interferometer should not be feasible.
49
„Rubidium resonant squeezed light from a diode-pumped optical-parametric oscillator“. Universitat Politècnica de Catalunya, 2009. http://www.tesisenxarxa.net/TDX-0915109-150004/.
50
Chelkowski, Simon [Verfasser]. „Squeezed light and laser interferometric gravitational wave detectors / von Simon Chelkowski“. 2007. http://d-nb.info/985987383/34.