Journal articles on the topic 'Interferometer'
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1
Pushin, D. A., M. G. Huber, M. Arif, C. B. Shahi, J. Nsofini, C. J. Wood, D. Sarenac, and D. G. Cory. "Neutron Interferometry at the National Institute of Standards and Technology." Advances in High Energy Physics 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/687480.
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Neutron interferometry has proved to be a very precise technique for measuring the quantum mechanical phase of a neutron caused by a potential energy difference between two spatially separated neutron paths inside interferometer. The path length inside the interferometer can be many centimeters (and many centimeters apart) making it very practical to study a variety of samples, fields, potentials, and other macroscopic medium and quantum effects. The precision of neutron interferometry comes at a cost; neutron interferometers are very susceptible to environmental noise that is typically mitigated with large, active isolated enclosures. With recent advances in quantum information processing especially quantum error correction (QEC) codes we were able to demonstrate a neutron interferometer that is insensitive to vibrational noise. A facility at NIST’s Center for Neutron Research (NCNR) has just been commissioned with higher neutron flux than the NCNR’s older interferometer setup. This new facility is based on QEC neutron interferometer, thus improving the accessibility of neutron interferometry to the greater scientific community and expanding its applications to quantum computing, gravity, and material research.
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Rodríguez, Luis F. "SpS1-Instrumentation for sub-millimeter spectroscopy." Proceedings of the International Astronomical Union 5, H15 (November 2009): 527–28. http://dx.doi.org/10.1017/s1743921310010525.
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The fields of millimeter and sub-millimeter interferometry have been developing for more than 30 years. At millimeter wavelengths the most important interferometers are the Combined Array for Research in Millimeter-Wave Astronomy (CARMA), the Plateau de Bure Interferometer (PdBI), and the Nobeyama Millimeter Array (NMA). At sub-millimeter wavelenghts, the most powerful interferometer is the SubMillimeter Array (SMA, for a detailed description, see Ho et al. 2004).
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Miyata, Kaoru, Hidekazu Oozeki, Hideyuki Nakagawa, Hiroki Masuda, and Hisayoshi Sakai. "Two-Wavelength Laser Interferometer System Which Reduces the Uncertainty Caused by the Fluctuation of the Refractive Index of Air." International Journal of Automation Technology 5, no. 2 (March 5, 2011): 126–31. http://dx.doi.org/10.20965/ijat.2011.p0126.
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Laser interferometers are widely used to measure highly sensitive length and displacement, e.g., in which refractive index fluctuations of air adversely affect measurement accuracy. To compensate for these effects, the two-wavelength interferometer studied has not yet proved practical in industrial use. We studied the interferometer’s performance and practicality, using uncertainty analysis to extract its features. Based on our results, we developed a two-wavelengthMichelson interferometer with wavelengths of 1064 nm and 532 nm. It was calibrated and evaluated using a highprecision laser interferometer whose optical path was in a vacuum. Results confirmed measurement accuracy of 100 nm/50 mm (k=2) under unstable air conditions - superior to a traditional laser interferometer.
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Pan, Xiaopei, Shri Kulkarni, Michael Shao, and M. Mark Colavita. "Narrow-Angle and Wide-Angle Astrometry via Long Baseline Optical/Infrared Interferometers." Symposium - International Astronomical Union 166 (1995): 13–18. http://dx.doi.org/10.1017/s0074180900227769.
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Long baseline optical/infrared interferometers, such as the Mark III Stellar Interferometer1 on Mt. Wilson and the ASEPS-0 Testbed Interferometer2 on Palomar Mountain, California, have good capabilities for narrow-angle and wide-angle astrometry with very high precision. Using the Mark III Interferometer many spectroscopic binaries became “visual” for the first time. The measurement accuracy of angular separation is 0.2 mas, the smallest separation measured between two components is 2 mas, the maximum magnitude difference is 4 mag, and the smallest semimajor axis is 4 mas. Such high angular resolution and dynamic range have been used to determine stellar masses with precision of 2% and differential stellar luminosities to better than 0.05 mag for separations of less than 0.″2. For some binary stars, not only have the systems been resolved, but also the diameter of the primary component has been determined, yielding direct measurements of stellar effective temperature with high accuracy. For parallax determination, the precision is 1 mas or better and is unaffected by interstellar extinction. For wide-angle astrometry with the Mark III interferometer, the observation results yielded average formal 1σ errors for FK5 stars of about 10 mas. Presently a new infrared interferometer, the ASEPS-0 Testbed Interferometer on Palomar Mountain is under construction, and is being optimized to perform high accuracy narrow-angle astrometry using long baseline observations at 2.2 μm, with phase referencing for increased sensitivity. The goal is to demonstrate differential astrometric accuracies of 0.06–0.1 mas3 in order to allow for detection of extra-solar planets in the near future.
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Scholz, Gregor, Ling Yang, Markus Schake, and Ines Fortmeier. "Concept for improving the form measurement results of aspheres and freeform surfaces in a tilted-wave interferometer." Journal of Sensors and Sensor Systems 13, no. 1 (May 15, 2024): 89–97. http://dx.doi.org/10.5194/jsss-13-89-2024.
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Abstract. Accurate and flexible form measurements for aspherical and freeform surfaces are in high demand, and non-null-test interferometric methods such as tilted-wave interferometry have gained attention as a promising response to this need. Interferometric methods, however, display ambiguities between the measurement of certain form errors and the misalignment of the measured specimen. Therefore, improved knowledge of the absolute measurement position of the specimen in relation to the interferometer setup may improve the form measurement result. In this work, we propose a concept that uses a white light interferometer to measure the absolute distance between a transparent specimen's surface and the interferometer's objective and present preparatory data to qualify the white light interferometer for the improvement of tilted-wave interferometer measurements.
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Ferreri, Alessandro, Matteo Santandrea, Michael Stefszky, Kai H. Luo, Harald Herrmann, Christine Silberhorn, and Polina R. Sharapova. "Spectrally multimode integrated SU(1,1) interferometer." Quantum 5 (May 27, 2021): 461. http://dx.doi.org/10.22331/q-2021-05-27-461.
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Nonlinear SU(1,1) interferometers are fruitful and promising tools for spectral engineering and precise measurements with phase sensitivity below the classical bound. Such interferometers have been successfully realized in bulk and fiber-based configurations. However, rapidly developing integrated technologies provide higher efficiencies, smaller footprints, and pave the way to quantum-enhanced on-chip interferometry. In this work, we theoretically realised an integrated architecture of the multimode SU(1,1) interferometer which can be applied to various integrated platforms. The presented interferometer includes a polarization converter between two photon sources and utilizes a continuous-wave (CW) pump. Based on the potassium titanyl phosphate (KTP) platform, we show that this configuration results in almost perfect destructive interference at the output and supersensitivity regions below the classical limit. In addition, we discuss the fundamental difference between single-mode and highly multimode SU(1,1) interferometers in the properties of phase sensitivity and its limits. Finally, we explore how to improve the phase sensitivity by filtering the output radiation and using different seeding states in different modes with various detection strategies.
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Samoylenko, O., O. Adamenko, and V. Kalynichenko. "The Method and the Results of the Direct Comparison of the Laser Interferometers Renishaw Xl-80." Metrology and instruments, no. 4 (August 30, 2018): 15–21. http://dx.doi.org/10.33955/2307-2180(4)2018.15-21.
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The method of the direct comparison of the laser interferometers and method processing of the interferometry measurement results by the least square method (LSM) is present. The additive part of the measurement error for each pair of the interferometers is evaluated and the multiplicative part of the measurement error for each interferometer is evaluated too by LSM. Uncertainty by A tape by LSM is evaluated for all parameters. Results of the comparison of the three interferometers are presented.
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Drozd, Alexey, and Dmitriy Sergeev. "Design of a phasemeter for real-time measurements of the average plasma density with the microwave interferometer of the tokamak T-15MD." Review of Scientific Instruments 93, no. 6 (June 1, 2022): 063501. http://dx.doi.org/10.1063/5.0087847.
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Interferometry is one of the key diagnostics for fusion research. This diagnostic measures electron plasma density. Interferometers that work on an intermediate frequency are widespread nowadays. The phase shift between interferometer signals has to be measured. The use of a microwave interferometer on machines, such as a tokamak, leads to challenging requirements for the phasemeter operation. We present a method to provide real-time measurements of phase shifts with values much higher than 2[Formula: see text]. The phasemeter has been designed for the microwave interferometer of the T-15MD tokamak. It is based on microcircuits AD8302. Two signals with frequencies of 5 and 10 MHz are used as interferometer outputs. The phasemeter output will be used to create a feedback loop for the working gas injection into the tokamak chamber to control the plasma density. The phasemeter has been successfully tested. The typical phase error and non-linearity of the device are 1° and 5 × 10−4, respectively.
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Prygunov, A. G., A. S. Kornev, and S. V. Lazarenko. "Estimation of the sensitivity of optical measurements using a holographic interferometer." Izmeritel`naya Tekhnika, no. 10 (November 17, 2023): 56–62. http://dx.doi.org/10.32446/0368-1025it.2023-10-56-62.
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Various interferometers used for high-precision spectroscopic measurements are considered, and the choice of a holographic interferometer based on the spatial-spectral method of holographic interferometry is justified, with the help of which the movements of the phase center of a coherent light flux in a wide dynamic range are measured in real time and measurement information is recorded digitally. On the basis of mathematical relations proposed by the authors in previous publications and based on the results of experimental studies, the sensitivity of a holographic interferometer to spatial displacements of phase centers (focus points) of light streams – point light sources forming a holographic interferogram is numerically estimated. The dependence of the level of the normalized intensity of the luminous flux in the central region of the holographic interferogram on the movement of the actual point light source along the normal to the plane of the Fourier hologram is established. Based on the results of mathematical modeling, it is shown that the sensitivity of the holographic interferometer to the movements of a real point light source along the normal to the plane of the Fourier hologram depends on the parameters of the optical scheme of the holographic interferometer when exposing the hologram and during measurements. At the same time, the sensitivity of the holographic interferometer to the indicated displacements of a real point light source can only be evaluated experimentally. It is proposed to increase the sensitivity of the holographic interferometer by using a thin collecting lens in its optical scheme. For the first time, a mathematical relation was obtained and investigated for the gain coefficient of the light flux phase with a spherical wavefront, which makes it possible to numerically estimate the increase in sensitivity of a holographic interferometer implementing the spatial-spectral method of holographic interferometry with known parameters of a thin collecting lens in an optical scheme. It is shown that the sensitivity of a holographic interferometer to the movements of an imaginary point light source along the normal to the plane of the Fourier hologram is 2.86 times greater than its sensitivity to the same movements of a real point light source. It is established that the sensitivity of a holographic interferometer with a volumetric Fourier hologram and a thin collecting lens in its design can be increased by at least an order of magnitude compared to the sensitivity of known optical interferometers. The results of assessing the sensitivity of a holographic interferometer implementing the spatial-spectral method of holographic interferometry to the movements of point sources of real and imaginary light fluxes, as well as the obtained ratio for the gain of the light flux phase gain by a thin collecting lens will be useful for high-precision measurements of linear and angular displacements of objects, as well as for the construction of photonic device designs. Based on the results of the study, an experimental sample of an acousto-electric converter was developed and manufactured on the basis of a holographic interferometer, which has high sensitivity in wide dynamic and frequency ranges and is intended for use in acoustic location of unmanned aerial vehicles.
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Fiorucci, D., A. Fassina, and M. La Matina. "Feasibility study of an enhanced heterodyne dispersion interferometer." Journal of Instrumentation 18, no. 02 (February 1, 2023): C02057. http://dx.doi.org/10.1088/1748-0221/18/02/c02057.
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Abstract Interferometry is the commonly exploited technique for electron density measurements in magnetically confined fusion plasma experiments. Reliable electron density measurements are fundamental both for machine protection and for plasma physics understanding. In the last years, attention was drawn on the dispersion interferometer concept, because of its robustness and simplicity. Nevertheless, the heterodyne version of this configuration, which has several advantages over the homodyne scheme, loses one of the main benefits of the dispersion interferometer technique, that is its inherent insensitivity to vibration errors. In this paper, two methods are proposed and theoretically investigated to reduce the vibration noise in the electron density measurements performed with heterodyne dispersion interferometers.
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Thuering, T., and M. Stampanoni. "Performance and optimization of X-ray grating interferometry." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 372, no. 2010 (March 6, 2014): 20130027. http://dx.doi.org/10.1098/rsta.2013.0027.
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The monochromatic and polychromatic performance of a grating interferometer is theoretically analysed. The smallest detectable refraction angle is used as a metric for the efficiency in acquiring a differential phase-contrast image. Analytical formulae for the visibility and the smallest detectable refraction angle are derived for Talbot-type and Talbot–Lau-type interferometers, respectively, providing a framework for the optimization of the geometry. The polychromatic performance of a grating interferometer is investigated analytically by calculating the energy-dependent interference fringe visibility, the spectral acceptance and the polychromatic interference fringe visibility. The optimization of grating interferometry is a crucial step for the design of application-specific systems with maximum performance.
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Guillen Bonilla, José Trinidad, Héctor Guillen Bonilla, Verónica María Rodríguez Betancourtt, María Eugenia Sánchez Morales, Juan Reyes Gómez, Antonio Casillas Zamora, and Alex Guillen Bonilla. "Low-Finesse Fabry–Pérot Interferometers Applied in the Study of the Relation between the Optical Path Difference and Poles Location." Sensors 20, no. 2 (January 13, 2020): 453. http://dx.doi.org/10.3390/s20020453.
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Interferometry sensors are frequently analyzed by applying the Fourier transform because the transformation separates all frequency components of its signal, making its study on a complex plane feasible. In this work, we study the relation between the optical path difference (OPD) and poles location theoretically and experimentally, using the Laplace transform and a pole-zero map. Theory and experiments are in concordance. For our study, only the cosine function was considered, which is filtered from the interference pattern. In experimental work, two unperturbed low-finesse Fabry–Pérot interferometers were used. First, a Fabry–Pérot interferometer that has a cavity length of ~ 1.6 mm was used. Its optical path difference was 2.33 mm and the poles were localized at points ± i 12 . rad/nm. Secondly, a Fabry–Pérot interferometer with a cavity length of ~ 5.2 mm was used, and its optical path difference was 7.59 mm and the poles were localized at points ± i 40.4 rad/nm. Experimental results confirmed the theoretical analysis. Our proposal finds practical application for interferometer analysis, signal processing of optical fiber sensors, communication system analysis, and multiplexing systems based on interferometers.
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Liang, Xinyun, Zhifei Yu, Chun-Hua Yuan, Weiping Zhang, and Liqing Chen. "Phase Sensitivity Improvement in Correlation-Enhanced Nonlinear Interferometers." Symmetry 14, no. 12 (December 19, 2022): 2684. http://dx.doi.org/10.3390/sym14122684.
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Interferometers are widely used as sensors in precision measurement. Compared with a conventional Mach–Zehnder interferometer, the sensitivity of a correlation-enhanced nonlinear interferometer can break the standard quantum limit. Phase sensitivity plays a significant role in the enhanced performance. In this paper, we review improvement in phase estimation technologies in correlation-enhanced nonlinear interferometers, including SU(1,1) interferometer and SU(1,1)-SU(2) hybrid interferometer, and so on, and the applications in quantum metrology and quantum sensing networks.
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Cavedo, Federico, Parisa Esmaili, Alessandro Pesatori, and Michele Norgia. "Self-mixing Interferometer: Frequency Modulation Noise Dependence on Laser Source." Journal of Physics: Conference Series 2698, no. 1 (February 1, 2024): 012019. http://dx.doi.org/10.1088/1742-6596/2698/1/012019.
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Abstract The acquisition of frequency modulation in self-mixing interferometry opens the way to a new generation of instruments, with significantly superior performance compared to traditional self-mixing interferometers. In this work, we experimentally confirm the noise limit dependence of this kind of interferometer on the laser source linewidth. The obtained results confirm the theoretical prediction, opening the way for a deeper improvement in sensitivity, by employing narrow-line lasers in this interferometric configuration.
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Müller, André F., Claas Falldorf, Gerd Ehret, and Ralf B. Bergmann. "Messen von asphärischen Linsenformen mittels räumlicher Kohärenz." tm - Technisches Messen 86, no. 6 (May 26, 2019): 325–34. http://dx.doi.org/10.1515/teme-2019-0025.
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ZusammenfassungWir zeigen den Vergleich zweier interferometrischer Verfahren zur Formprüfung anhand einer Messung an einer Zylinderlinse. Das erste Verfahren, die Multiple Aperture Shear Interferometry (MArS), basiert auf der Messung der Kohärenzfunktion mittels eines Scher-Interferometers. Es erlaubt interferometrische Messungen unter gleichzeitiger Verwendung mehrerer unabhängiger und teilkohärenter Lichtquellen, und ermöglicht so eine flexible, an den Prüfling anpassbare Ausleuchtung. Als Vergleichsverfahren kommt die Computational Shear Interferometry (CoSI) zur Messung von Wellenfronten zum Einsatz. Da beide Messverfahren auf einem Scher-Interferometer basieren, ist ein direkter Vergleich unter identischen Umgebungsbedingungen möglich.
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Mazzotta, C. "Review of SIRIO interferometer experimental results." Journal of Instrumentation 18, no. 08 (August 1, 2023): C08007. http://dx.doi.org/10.1088/1748-0221/18/08/c08007.
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Abstract The SIRIO (Scanning InfraRed Interferometer) interferometer [1], recently disassembled together with the FTU (Frascati Tokamak Upgrade) experiment [2], worked continuously from 2004 to 2019. An extremely important contribution was made in all the experiments conducted on this tokamak. By virtue of its characteristics, in terms of spatial (1 cm) and temporal resolution (density profiles every 62 μs), combined with its capability to scan the entire plasma column. This interferometer produced all the density feedbacks for operations. Above all, it collected accurate density measurements in plasma physics, among the best data of all tokamak interferometers. In this review, it is reported the highly valuable experimental work of this powerful diagnostics. Indeed, high density observations were analyzed, as well as fast variations were measured; some examples: the detection of plasma instabilities (MARFE), the trace and the speed of the pellets, the measurement of the particle transport efficiencies in important transients etc. In order to improve the knowledge for future interferometry in plasma density measurements projects, some topics related to data analysis are also exposed, as well as local density reconstruction methods.
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Ohtani, Y., and R. Imazawa. "Conceptual design and demonstration of a three-color laser interferometer for noise reduction in fusion plasma measurements." Review of Scientific Instruments 94, no. 1 (January 1, 2023): 013502. http://dx.doi.org/10.1063/5.0128536.
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A three-color laser interferometer consisting of three Mach–Zehnder-type, one-color laser interferometers with heterodyne detection and coaxial laser beams is demonstrated. The three-color laser interferometer is considered as three sets of a two-color laser interferometer. From the two sets of the two-color laser interferometer, the value consisting only of the noise floor can be assessed. The noise floor can be reduced by subtracting the value consisting only of the noise floor from the measurement value obtained with the other two-color laser interferometer. In the case of the three lasers with wavelengths 9.25 μm, 10.59 μm, and 532 nm, a 15% noise reduction was obtained compared to the two sets of the two-color laser interferometers contained in the three-color laser interferometer. The 100-Hz noise reduction by 53% was achieved, and the other frequency noises were equal to or less than the smallest noise achieved by the two-color laser interferometers. The 100-Hz noise floor is caused by the vibration noise, which remains because of the non-coaxiality of the three beams.
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Li, Huicong, Minggan Lou, Wenzhu Huang, and Wentao Zhang. "Real-Time Measurement and Uncertainty Evaluation of Optical Path Difference in Fiber Optic Interferometer Based on Auxiliary Interferometer." Sensors 24, no. 7 (March 22, 2024): 2038. http://dx.doi.org/10.3390/s24072038.
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Optical interferometers are the main elements of interferometric sensing and measurement systems. Measuring their optical path difference (OPD) in real time and evaluating the measurement uncertainty are key to optimizing system noise and ensuring system consistency. With the continuous sinusoidal wavelength modulation of the laser, real-time OPD measurement of the main interferometer is achieved through phase comparison of the main and auxiliary interferometers. The measurement uncertainty of the main interferometer OPD is evaluated. It is the first evaluation of the impact of different auxiliary interferometer calibration methods on OPD measurements. A homodyne quadrature laser interferometer (HQLI) is used as the main interferometer, and a 3 × 3 interferometer is used as the auxiliary interferometer. The calibration of the auxiliary interferometer using optical spectrum analyzer scanning and ruler measurement is compared. The evaluation shows that the auxiliary interferometer is the most significant source of uncertainty and causes the total uncertainty to increase linearly with increasing OPD. It is proven that a high-precision calibration and large-OPD auxiliary interferometer can improve the real-time accuracy of OPD measurements based on the auxiliary interferometer. The scheme can determine the minimum uncertainty to optimize the system noise and consistency for vibration, hydroacoustic, and magnetic field measurements with OPDs of the ~m level.
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Kol'tso, N. E., S. A. Grenkov, and L. V. Fedotov. "Comparison of Radio Interferometers with Analog and Digital Extraction of Recorded Signal." Journal of the Russian Universities. Radioelectronics 23, no. 2 (April 28, 2020): 6–18. http://dx.doi.org/10.32603/1993-8985-2020-23-2-6-18.
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Introduction. Radio telescopes of Very Long Baseline Interferometry (VLBI) networks usually record several signals with relatively narrow (up to 32 MHz) bands, which are extracted by means of base band converters (BBC) from an analog noise signal of an intermediate frequency (IF) with bands up to 1 GHz. When processing data, frequency band synthesis is used. At new small radio telescopes (for example, RT-13), directly wideband IF signals are digitized. An ability to connect the RT-13 radio telescope to the “Quasar” VLBI complex and to international VLBI networks provides by a digital narrow-band signal extraction module developed in 2019.Aim. Determining the measuring accuracy of an interferometric group delay of a signal by a radio interferometer with a digital narrow-band signal extraction module and comparing the sensitivity of interferometers with analog and digital signal extraction systems.Materials and methods. Sensitivity losses of interferometers with different systems for detecting recorded signals were calculated. The accuracy of a multi-channel interferometer with the synthesis of a frequency band and of an interferometer with recording of digital broadband IF signals without band synthesis was compared. The results were confirmed by VLBI observations in the observatories of the “Quasar” complex.Results. When replacing the analog system of signal extraction with digital system the sensitivity losses of the interferometer were slightly reduced. The measurement accuracy of the interferometric group delay had not changed. Accuracy increased when digitally recording broadband IF signals and when synthesizing a frequency band significantly larger than the IF bandwidth. Conditions and minimum synthesized bands were determined under which the accuracy of the interferometer with the registration of narrowband signals can be higher than the accuracy of the interferometer with the registration of wideband IF signals.Conclusion. The problem of combining RT-13 radio telescopes with VLBI networks with recording of video frequency signals was solved. The efficiency of the installation of digital signal conversion systems at radio telescopes was shown.
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Swain, Mark R. "The Antarctic Planet Interferometer." Highlights of Astronomy 13 (2005): 962–63. http://dx.doi.org/10.1017/s1539299600017792.
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AbstractThe Antarctic Planet Interferometer (API) is a concept for an infrared interferometer located at the best accessible site on Earth. Infrared interferometry is strongly effected by both the strength and vertical distribution of thermal and water vapor turbulence. The combination of low temperature, low wind speed, low elevation turbulence, and low precipitable water vapor make the Concordia base at Antarctic Dome C the best accessible site on Earth for infrared interferometry. The improvements in interferometer sensitivity with respect to other terrestrial sites are dramatic; an interferometer with two meter class telescopes could make unique infrared measurements of extra solar planets that might otherwise only be possible with a space-based interferometer.
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Chesneau, O., K. Rousselet-Perraut, and F. Vakili. "Interferometry and Stellar Magnetism." International Astronomical Union Colloquium 175 (2000): 174–77. http://dx.doi.org/10.1017/s0252921100055792.
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AbstractThe classical detection of magnetic fields in Be stars remains a challenge due to the sensitivity threshold and geometrical cancelation of the field effects. We propose to study the Zeeman effect using Spectro-Polarimetric INterferometry (SPIN) which consists of the simultaneous use of polarimetry and very high angular resolution provided by long baseline interferometers. As monitoring of the instrumental polarisation is mandatory in order to calibrate interferometric observations in any case, the polarised signal is a natural by-product of interferometers. This method will be tested on the GI2T interferometer thanks to its high spectral resolution and its polarimetric capabilities.
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Aydin, Deniz, Jack A. Barnes, and Hans-Peter Loock. "In-fiber interferometry sensors for refractive index." Applied Physics Reviews 10, no. 1 (March 2023): 011307. http://dx.doi.org/10.1063/5.0105147.
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Compact interferometers based on waveguiding structures have found countless applications in refractive index measurements, chemical sensing, as well as temperature and pressure measurements. The most common fiber devices are based on Mach–Zehnder interferometry and Michelson interferometry—two design concepts that can readily be implemented using simple fiber optic components, such as mode splitters and combiners, fiber optic gratings, and fiber tapers, among others. Fiber interferometry can also be conducted based on the Sagnac effect and the Young (double-slit) interferometer. In this review, we examine and compare over 400 fiber optic interferometers as well as more than 60 fiber optic refractive sensors based on fiber optic cavities. Even though many of the devices show temperature-, strain-, and pressure-sensitivity, we focus our review on refractive index measurements, as these are the most common applications. Many devices were characterized by their inventors using their sensitivity to refractive index changes. While the sensitivity is an important characteristic of the device, it does not easily relate to the smallest resolvable refractive index change or the limit of detection when applied to chemical measurements. Instead, we propose here that one should use the figure of merit, which is defined through the refractive index sensitivity and the width of an interferometer fringe. Using simple assumptions, we were able to mathematically relate the sensitivity and the figure of merit to common design parameters, such as the length of the interferometer arms, the operating wavelength, refractive indices of the fiber and the sample, as well as an overlap parameter, which describes the fraction of the guided wave in the sensing arm that interacts with the sample. We determined this overlap parameter for each reviewed device from the reported interferograms. Our meta-analysis provides for the first time simple and easily applicable guidance to increase the figure of merit of fiber optic interferometers and fiber optic cavities with regard to their ability to detect small refractive index changes. A high figure of merit allows measuring very small refractive index changes such as those of gases at different pressures or of very dilute solutions.
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Yao, Y., W. Li, Y. Zhang, Y. Song, H. Liu, and Y. Jie. "Design of real-time data acquisition system for interferometer-based electron density diagnostics on EAST." Review of Scientific Instruments 93, no. 3 (March 1, 2022): 034705. http://dx.doi.org/10.1063/5.0043874.
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Laser-aided interferometers are employed as the common diagnostics for electron density measurements. On the EAST (Experimental Advanced Superconducting Tokamak), we have four main electron density diagnostics—the far-infrared hydrogen cyanide interferometer, polarimeter/interferometer, carbon dioxide (CO2) dispersion interferometer, and solid-state source interferometer. For interferometers, the phase difference brought by the change in electron density can be acquired via mixers. A real-time data acquisition (DAQ) system is needed to calculate the highly precise density values. In this paper, a field-programmable gate array is employed to implement the system with fast Fourier transform-based demodulation technology. A highly precise analog/digital converter is employed for readout and digitization of the waveform including multiple frequency signals from high-performance Schottky mixers. The system has been simulated, and the results show that it can meet the requirements of the accuracy of interferometers on the EAST. Furthermore, the framework of the DAQ system also offers a reference of the data processing method to the future laser-aided interferometers.
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He, Mengyun, Yu Huang, Huimin Sun, Yu Fu, Peng Zhang, Chenbo Zhao, Kang L. Wang, Guoqiang Yu, and Qing Lin He. "Quantum anomalous Hall interferometer." Journal of Applied Physics 133, no. 8 (February 28, 2023): 084401. http://dx.doi.org/10.1063/5.0140086.
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Electronic interferometries in integer and fractional quantum Hall regimes have unfolded the coherence, correlation, and statistical properties of interfering constituents. This is addressed by investigating the roles played by the Aharonov–Bohm effect and Coulomb interactions on the oscillations of transmission/reflection. Here, we construct magnetic interferometers using Cr-doped (Bi,Sb)2Te3 films and demonstrate the electronic interferometry using chiral edge states in the quantum anomalous Hall regime. By controlling the extent of edge coupling and the amount of threading magnetic flux, distinct interfering patterns were observed, which highlight the interplay between the Coulomb interactions and Aharonov–Bohm interference by edge states. The observed interference is likely to exhibit a long-range coherence and robustness against thermal smearing probably owing to the long-range magnetic order. Our interferometer establishes a platform for (quasi)particle interference and topological qubits.
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Polavarapu, Prasad L. "Double Polarization Modulation Interferometry." Applied Spectroscopy 51, no. 6 (June 1997): 770–77. http://dx.doi.org/10.1366/0003702971941197.
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The concepts of a double polarization modulation interferometer and the experimental measurements verifying these concepts are presented. This interferometer serves as an analytical tool for the characterization of polarization modulation devices. In addition, for polarization difference measurements this interferometer offers four times better efficiency over widely used amplitude-division interferometers.
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Yang, Yichao, Kohei Yamamoto, Victor Huarcaya, Christoph Vorndamme, Daniel Penkert, Germán Fernández Barranco, Thomas S. Schwarze, et al. "Single-Element Dual-Interferometer for Precision Inertial Sensing." Sensors 20, no. 17 (September 3, 2020): 4986. http://dx.doi.org/10.3390/s20174986.
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Tracking moving masses in several degrees of freedom with high precision and large dynamic range is a central aspect in many current and future gravitational physics experiments. Laser interferometers have been established as one of the tools of choice for such measurement schemes. Using sinusoidal phase modulation homodyne interferometry allows a drastic reduction of the complexity of the optical setup, a key limitation of multi-channel interferometry. By shifting the complexity of the setup to the signal processing stage, these methods enable devices with a size and weight not feasible using conventional techniques. In this paper we present the design of a novel sensor topology based on deep frequency modulation interferometry: the self-referenced single-element dual-interferometer (SEDI) inertial sensor, which takes simplification one step further by accommodating two interferometers in one optic. Using a combination of computer models and analytical methods we show that an inertial sensor with sub-picometer precision for frequencies above 10 mHz, in a package of a few cubic inches, seems feasible with our approach. Moreover we show that by combining two of these devices it is possible to reach sub-picometer precision down to 2 mHz. In combination with the given compactness, this makes the SEDI sensor a promising approach for applications in high precision inertial sensing for both next-generation space-based gravity missions employing drag-free control, and ground-based experiments employing inertial isolation systems with optical readout.
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de Haan, Victor. "Asymmetric Mach–Zehnder fiber interferometer test of the anisotropy of the speed of light." Canadian Journal of Physics 87, no. 10 (October 2009): 1073–78. http://dx.doi.org/10.1139/p09-080.
Full textAbstract:
Two optical fiber Mach–Zehnder interferometers were constructed in an environment with a temperature stabilization of better than 1 mK per day. One interferometer with a length of 2 m optical fiber in each arm with the main direction of the arms parallel to each other. A path (length 175 mm) filled with atmospheric air is inserted in one arm. Another interferometer with a length of 2 m optical fiber in each parallel arm acts as a control. In one of the arms in each interferometer, 1 m of fiber was wound around a ring made of piezo material enabling the control of the length of the arms by means of a voltage. The influence of rotation of the interferometers at the Earth's surface on the observed phase differences was determined. For one interferometer (with the air path) it was found that the phase difference depends on the azimuth of the interferometer. For the other one no relevant dependence on the azimuth has been measured.
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Rudenko, Valentin, Svetlana Andrusenko, Daniil Krichevskiy, and Gevorg Manucharyan. "GW Interferometer Euro-Asian Network: Detection Characteristics for Signals of Known Shape." Universe 6, no. 9 (September 2, 2020): 140. http://dx.doi.org/10.3390/universe6090140.
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In this paper, we estimate efficiency of a conceivable Euro-Asian network of gravitational wave (GW) interferometers that might be realized having in mind a plan of construction of third generation interferometer in Novosibirsk region. Subsequently, some network would be composed, including four GW detectors. Among them there are the already active interferometers VIRGO (Italy) and KAGRA (Japan), Indian interferometer under construction—LIGO India and the interferometer in Siberia mentioned above. The quality of network in question is considered on the base of typical numerical criteria of efficiency for detecting GW signals of known structure—radiation of relativistic binary coalescence.
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Vu, Thanh Tung, Hong Hai Hoang, Toan Thang Vu, and Ngoc Tam Bui. "A Displacement Measuring Interferometer Based on a Frequency-Locked Laser Diode with High Modulation Frequency." Applied Sciences 10, no. 8 (April 13, 2020): 2693. http://dx.doi.org/10.3390/app10082693.
Full textAbstract:
Laser interferometers can achieve a nanometer-order uncertainty of measurements when their frequencies are locked to the reference frequencies of the atom or molecule transitions. There are three types of displacement-measuring interferometers: homodyne, heterodyne, and frequency modulation (FM) interferometers. Among these types of interferometer, the FM interferometer has many advantageous features. The interference signal is a series of time-dependent harmonics of modulation frequency, so the phase shift can be detected accurately using the synchronous detection method. Moreover, the FM interferometer is the most suitable for combination with a frequency-locked laser because both require frequency modulation. In previous research, low modulation frequencies at some tens of kHz have been used to lock the frequency of laser diodes (LDs). The low modulation frequency for the laser source means that the maximum measurement speed of the FM interferometers is limited. This paper proposes a novel contribution regarding the application of a high-frequency modulation for an LD to improve both the frequency stability of the laser source and the measurement speed of the FM interferometer. The frequency of the LD was locked to an I2 hyperfine component at 1 MHz modulation frequency. A high bandwidth lock-in amplifier was utilized to detect the saturated absorption signals of the I2 hyperfine structure and induce the signal to lock the frequency of the LD. The locked LD was then used for an FM displacement measuring interferometer. Moreover, a suitable modulation amplitude that affected the signal-to-noise ratio of both the I2 absorption signal and the harmonic intensity of the interference signal was determined. In order to verify the measurement resolution of the proposed interferometer, the displacement induced by a piezo electric actuator was concurrently measured by the interferometer and a capacitive sensor. The difference of the displacement results was less than 20 nm. To evaluate the measurement speed, the interferometer was used to measure the axial error of a high-speed spindle at 500 rpm. The main conclusion of this study is that a stable displacement interferometer with high accuracy and a high measurement speed can be achieved using an LD frequency locked to an I2 hyperfine transition at a high modulation frequency.
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Eckhardt, Tobias, and Oliver Gerberding. "Noise Limitations in Multi-Fringe Readout of Laser Interferometers and Resonators." Metrology 2, no. 1 (February 19, 2022): 98–113. http://dx.doi.org/10.3390/metrology2010007.
Full textAbstract:
Laser interferometers that operate over a dynamic range exceeding one wavelength are used as compact displacement sensors for gravitational wave detectors and inertial sensors and in a variety of other high-precision applications. A number of approaches are available to extract the phase from such interferometers by implementing so-called phasemeters, algorithms to provide a linearised phase estimate. While many noise sources have to be considered for any given scheme, they are fundamentally limited by additive noise in the readout, such as electronic readout, digitisation, and shot-noise, which manifest as an effective, white phase noise in the phasemeter output. We calculated and compared the Cramer–Rao lower bound for phasemeters of some state-of-the-art two-beam interferometer schemes and derived their noise limitations for sub-fringe operation and for multi-fringe readout schemes. From this, we derived achievable noise performance levels for one of these interferometer techniques, deep-frequency modulation interferometry. We then applied our analysis to optical resonators and show that frequency scanning techniques can in theory benefit from such resonant enhancement, indicating that the sensitivities can be improved in future sensors.
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VETRANO, FLAVIO, GIANLUCA M. GUIDI, ANDREA VICERÉ, QUENTIN BODART, YU-HUNG LIEN, MARCO PREVEDELLI, GABRIELE ROSI, FIODOR SORRENTINO, and GUGLIELMO M. TINO. "PRINCIPLES OF GRAVITATIONAL WAVES DETECTION THROUGH ATOM INTERFEROMETRY." International Journal of Modern Physics: Conference Series 23 (January 2013): 135–43. http://dx.doi.org/10.1142/s2010194513011185.
Full textAbstract:
The output of a simple Mach-Zehnder atom interferometer (with light field beam splitters) is studied in order to obtain sensitivity curves for GW signals in the paraxial approximation by using the ABCD matrices techniques and first order perturbation theory for mirroratom interaction; order of magnitude of relevant physical parameters for a realistic GW detector through atom interferometry is deduced, both for single- and coupled-interferometers configurations. Finally a synthetic overview of ongoing activities of the Florence-Urbino group in this field is presented.
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Khokhlov, Dmitri. "Quantum non-demolition measurement in the interferometer." International Journal of Physical Research 9, no. 1 (December 27, 2020): 7. http://dx.doi.org/10.14419/ijpr.v9i1.31243.
Full textAbstract:
The schemes of the arrangements based on the Mach-Zehnder interferometer and the interferometer with two polarizing beam splitters are considered. The interferometers in both the schemes are equipped with some devices, creating a Kerr medium, to perform the quantum non-demolition measurement of a single photon. Such a device gives which way information of the photon while preserving the work of the interferometer.
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Yu, Juan, Yinhua Wu, Liang Nie, and Xiaojie Zuo. "High-Sensitivity Quantum-Enhanced Interferometers." Photonics 10, no. 7 (June 29, 2023): 749. http://dx.doi.org/10.3390/photonics10070749.
Full textAbstract:
High-sensitivity interferometers are one of the basic tools for precision measurement, and their sensitivity is limited by their shot noise limit (SNL), which is determined by vacuum fluctuations of the probe field. The quantum interferometer with novel structures can break the SNL and measure the weak signals, such as the direct observation of gravity wave signal. Combining classical interferometers and the optical parametric amplifier (OPA) can enhance the signal; meanwhile, the quantum noise is kept at the vacuum level, so that the sensitivity of the nonlinear interferometer beyond the SNL can be achieved. By analyzing in detail the influence of system parameters on the precision of quantum metrology, including the intensity of optical fields for phase sensing, the gain factor of OPA, and the losses inside and outside the interferometers, the application conditions of high-sensitivity nonlinear quantum interferometers are obtained. Quantum interferometer-based OPAs provide the direct references for the practical development of quantum precise measurement.
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Zhao, Ya, Zhi Wang, Yupeng Li, Chao Fang, Heshan Liu, and Huilong Gao. "Method to Remove Tilt-to-Length Coupling Caused by Interference of Flat-Top Beam and Gaussian Beam." Applied Sciences 9, no. 19 (October 1, 2019): 4112. http://dx.doi.org/10.3390/app9194112.
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We discuss the tilt-to-length (TTL) coupling noise caused by interference between a flat-top beam and a Gaussian beam. Several physical models are presented to research the effects of non-diffracted and diffracted beams on TTL noise. A special case that can remove TTL coupling noise is discovered and is verified via both theoretical analysis and numerical simulations. The proposed case could provide desirable suggestions for the construction of high-precision interferometers such as the Laser Interferometer Space Antenna (LISA), Taiji program, or other interferometry systems.
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Xiao, Longfei, Hengfei Wang, Canhua Xu, and Yantang Huang. "Research the Nonlinear Frequency Modulation of Tunable Light Source to Improve the Spatial Resolution of OFDR." Journal of Physics: Conference Series 2464, no. 1 (March 1, 2023): 012015. http://dx.doi.org/10.1088/1742-6596/2464/1/012015.
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Abstract The main factor affecting the optical fiber spatial resolution of OFDR system is the non-linearity of laser frequency tuning.We demonstrated a M-Z interferometry and performed nonlinear measurements at different frequencies. The main and auxiliary interferometers with tunable laser source(TLS) were built, and the auxiliary interferometer was used to correct the nonlinearity modulation of the frequecny of the main laser.The interpolation compensation scheme was proposed.The research results of the nonlinear frequency modulation of TLS to improve the spatial resolution of optical fiber vibration sensing was demonstrated,the spatial resolution is 0.17m.
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Sałbut, Leszek, Dariusz Łukaszewski, and Aleksandra Piekarska. "Grating (Moiré) Microinterferometric Displacement/Strain Sensor with Polarization Phase Shift." Sensors 24, no. 9 (April 26, 2024): 2774. http://dx.doi.org/10.3390/s24092774.
Full textAbstract:
Grating (moiré) interferometry is one of the well-known methods for full-field in-plane displacement and strain measurement. There are many design solutions for grating interferometers, including systems with a microinterferometric waveguide head. This article proposes a modification to the conventional waveguide interferometer head, enabling the implementation of a polarization fringe phase shift for automatic fringe pattern analysis. This article presents both the theoretical considerations associated with the proposed solution and its experimental verification, along with the concept of in-plane displacement/strain sensing using the described head.
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Gut, Kazimierz. "Broadband differential interference in a waveguide with a gradient refractive index distribution." Photonics Letters of Poland 14, no. 3 (September 30, 2022): 53. http://dx.doi.org/10.4302/plp.v14i3.1157.
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The paper presents a model of a planar broadband differential waveguide interferometer with a gradient refractive index distribution. Its response to the change in the refractive index of the waveguide cover layer is presented. The analysis was performed for the wavelength range from 0.5um to 0.7um. The orthogonal TE0 and TM0 modes propagating in this wavelength range are considered. The influence of the coverage refractive index change on the output characteristics of the system is shown. Full Text: PDF ReferencesP. Kozma, F. Kehl, E.Ehrentreich-Forster, C. Stamm and F.F. Bier, "Integrated planar optical waveguide interferometer biosensors: A comparative review", Biosens. Bioelectron. 58, 287 (2014), CrossRef M. Kitsara, K. Misiakos, I. Raptis, and E. Makarona, "Integrated optical frequency-resolved Mach-Zehnder interferometers for label-free affinity sensing", Opt. Express 18, 8193 (2010). CrossRef K. Misiakos, I. Raptis, A. Salapatas, E. Makarona, A. Bostials, et al., "Broad-band Mach-Zehnder interferometers as high performance refractive index sensors: Theory and monolithic implementation", Opt. Express 22, 8856 (2014). CrossRef K. Misiakos, I. Raptis, E. Makarona, A. Botsialas, A. Salapatas, et al, "All-silicon monolithic Mach-Zehnder interferometer as a refractive index and bio-chemical sensor", Opt. Express 22, 26803 (2014) CrossRef K. Misiakos, E. Makarona, M. Hoekman, R. Fyrogenis, K. Tukkiniemi, et al., "All-Silicon Spectrally Resolved Interferometric Circuit for Multiplexed Diagnostics: A Monolithic Lab-on-a-Chip Integrating All Active and Passive Components", ACS Photonics 6, 1694 (2019). CrossRef E. Makarona, A. Salapatas, I. Raptis, P. Petrou, S. Kakabakos, et al., "Broadband Young interferometry for simultaneous dual polarization bioanalytics", J Opt Soc Am B 34, 1691 (2017). CrossRef K. Gut, "Broad-band difference interferometer as a refractive index sensor", Opt. Express 25, 3111 (2017), CrossRef K. Gut, "Study of a Broadband Difference Interferometer Based on Low-Cost Polymer Slab Waveguides", Nanomaterials 9, 729 (2019), CrossRef T. Pustelny, J. Ignac-Nowacka and Z. Opilski, "Optical investigations on layered metalphthalocyanine nanostructures affected by NO2 applying the surface plasmon resonance method", Opt. Appl. 34, 563 (2004). CrossRef W. Lukosz, Sensor Actuat. B-Chem. "Integrated optical chemical and direct biochemical sensors", 29, 37 (1995). CrossRef Z. Qi, S. Xia and N. Matsuda, "Spectropolarimetric interferometer based on single-mode glass waveguides", Opt. Express, 16, 2245 (2008). CrossRef K. Gut, A. Zakrzewski, T. Pustelny, "Sensitivity of Polarimetric Waveguide Interferometer for Different Wavelengths", Acta Phys. Pol. 118, 1140 (2010). CrossRef J.E. Broquin, S. Honkanen, "Integrated Photonics on Glass: A Review of the Ion-Exchange Technology Achievements", Appl.Sci. 11, 4472 (2021). CrossRef G.C. Righini, J. Linares, "Active and Quantum Integrated Photonic Elements by Ion Exchange in Glass", Appl.Sci. 11, 5222 (2021). CrossRef
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Belkora, L., Tor Hagfors, and J. A. Phillips. "A test of Radio Interferometry by Lunar reflection." International Astronomical Union Colloquium 131 (1991): 433–36. http://dx.doi.org/10.1017/s0252921100013786.
Full textAbstract:
AbstractWe discuss the use of the moon as a passive reflector for radio interferometry experiments with baselines on the order of the radius of the orbit of the moon. Because of the extreme loss in the lunar interferometer path, only exceptionally strong point sources are candidates for this kind of interferometry. As the moon is far from an ideal reflector due to the irregular surface, the data processing necessary to optimize the fringe detectability is rather complicated. What we present here is a very brief summary of a paper describing the lunar interferometer in the Astrophysical Journal (Hagfors, Phillips and Belkora, 1990) and an experiment currently underway at Arecibo to test the lunar interferometer using Jupiter’s strong bursts at 25 MHz as a source. All references pertaining to the lunar interferometer are to be found in the Astrophysical Journal paper; this summary includes references concerning the test of the interferometer at Arecibo.
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Mamadjanov, A. I., A. Turgunov, and M. Umaraliyev. "INVESTIGATE THE DEPENDENCE OF THE LIGHT REFRACTIVE INDEX OF AN IDEAL GAS ON ITS PRESSURE USING INTERFEROMETERS." International Journal of Advanced Research 8, no. 12 (December 31, 2020): 272–79. http://dx.doi.org/10.21474/ijar01/12147.
Full textAbstract:
This article analyzes the working principle of the Michelson interferometer and the ability to measure some physical quantities. Using the Michelson Interferometer, the ability to detect not only the light wave but also the full wavelength of radio waves was analyzed. Using the Mach-Zehnder and Michelson interferometers, it was determined that the refractive index of air depends on its pressure. The results obtained in two different interferometers were compared comparatively in the graphs.
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Salykina, Dariya, and Farid Khalili. "Sensitivity of Quantum-Enhanced Interferometers." Symmetry 15, no. 3 (March 22, 2023): 774. http://dx.doi.org/10.3390/sym15030774.
Full textAbstract:
We review various schemes of quantum-enhanced optical interferometers, both linear (SU(2)) and non-linear (SU(1,1)) ones, as well as hybrid SU(2)/SU(1,1) options, using the unified modular approach based on the Quantum Cramèr–Rao bound (QCRB), and taking into account the practical limitations pertinent to all real-world highly-sensitive interferometers. We focus on three important cases defined by the interferometer symmetry: (i) the asymmetric single-arm interferometer; (ii) the symmetric two-arm interferometer with the antisymmetric phase shifts in the arms; and (iii) the symmetric two-arm interferometer with the symmetric phase shifts in the arms. We show that while the optimal regimes for these cases differ significantly, their QCRBs asymptotically correspond to the same squeezing-enhanced shot noise limit (2), which first appeared in the pioneering work by C. Caves in 1981.We show also that in all considered cases the QCRB can be asymptotically saturated by the standard (direct or homodyne) detection schemes.
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Maksimova L.A., Mysina N.Y., Patrushev B.A., and Ryabukho V.P. "Diffraction mathematical model of a laser speckle interferometer of transverse displacements of a scattering object." Technical Physics 68, no. 4 (2023): 490. http://dx.doi.org/10.21883/tp.2023.04.55941.3-23.
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On the basis of diffraction transformations of wave fields, a mathematical model of a speckle interferometer of transverse displacements of a scattering object has been developed and numerical modeling of speckle-modulated interference patterns and signals at the output of the interferometer has been performed. Numerical calculations of the spatial distribution of complex amplitudes of wave fields in an interferometer were used for modeling when the displaced scattering surface was illuminated by two obliquely incident laser Gaussian beams. A statistical numerical experiment was performed to determine the measurement error of the scattering surface displacement caused by the change of realizations of interfering speckle fields. The simulation results are in good agreement with the results of experimental studies of transverse displacements in the range up to 600 micrometers. Keywords: interferometry, diffraction, interference, laser interferometer, speckle interferometry, interference pattern, speckle modulation, computer simulation.
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Trolinger, James D., Amit Lal, Joshua Jo, and Stephen Kupiec. "Programmable Holographic Optical Elements as Adaptive Optics in Optical Diagnostics Devices." Key Engineering Materials 437 (May 2010): 108–12. http://dx.doi.org/10.4028/www.scientific.net/kem.437.108.
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This paper reports a combined, Hartmann/Digital Holographic interferometry inspection system for inspecting optical components that do not easily lend themselves to conventional interferometric or Hartmann inspection. A programmable holographic optical element (HOE) preconditions wavefronts to extend the dynamic range of interferometry measurements and also transforms the same system into a scanning Hartmann operation, which has lower resolution but higher dynamic range. Inspecting aspherical surfaces with existing interferometers requires special, computer generated holographic optical elements to transform the wavefront to within the dynamic range of the interferometer. The Hartmann measurement provides the information required to precondition a reference wave that avails the measurement process to the more precise phase shifting interferometry. The SLM offers yet other benefits including a method for minimizing the effects of speckle on the measurement. The paper provides example measurements, discusses the limitations, and suggests other potential applications.
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Liu, X., Y. Gao, Suet To, and Wing Bun Lee. "Anti-Vibration Characteristics of a Lateral Shear Interferometer for On-Machine Surface Measurement." Key Engineering Materials 295-296 (October 2005): 411–16. http://dx.doi.org/10.4028/www.scientific.net/kem.295-296.411.
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Lateral shear interferometers have large measurement range and good anti-disturbance ability. They have similar accuracy compared with the reference based interferometers. Based on a specially designed shear generator, a new lateral shear interferometer is proposed. The new system has a complete common optical path and a simple mechanism. The optical model of the interferometer is presented and the anti-vibration characteristics are analyzed. To validate its antivibration ability for on-machine surface measurement, experimental tests have been conducted and results presented.
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Quirrenbach, A. "Stellar Diameters, Limb Darkening, Extended Atmospheres, and Shells: Observations with the MKIII Interferometer." Symposium - International Astronomical Union 158 (1994): 407–9. http://dx.doi.org/10.1017/s007418090010806x.
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The resolution of close binaries and direct measurements of stellar angular diameters were the first achievements of astronomical interferometry (Michelson and Pease 1921). Fringe tracking interferometers are now capable of producing visibility measurements which are sufficiently sensitive and well-calibrated to make more sophisticated measurements possible. Results from current instruments include measurements of limb darkening, of the wavelength-dependence of stellar diameters, and of non-spherical stars, and observations with narrow spectral bands. This paper summarizes recent results from the MkIII interferometer, concentrating on single stars and their envelopes. More detailed descriptions of the instrument and the data reduction procedures are given by Mozurkewich et al. (1991).
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Stee, Ph, D. Bonneau, F. Morand, D. Mourard, and F. Vakili. "Current studies and future prospects in stellar-structure imaging with the GI2T." Symposium - International Astronomical Union 176 (1996): 191–98. http://dx.doi.org/10.1017/s0074180900083224.
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The capability of optical long baseline interferometry for measuring the angular diameter of stars or binary separation is now well established. However, for the imaging of photospheric disk structures one needs very long baseline interferometers operated in the multi-telescope phase-closure technique. In this paper we will stress the capability of spectro-interferometric measurements to constrain the physics of hot stars. We will report our study of the interacting binary, β Lyrae, and the mass-losing Be star γ Cassiopeiae. We will look at the interpretation of both the modulus and phase data recorded by the long baseline interferometer GI2T in the southern France. The performances and limitations of spectro-interferometric techniques will also be discussed through some of the most exciting prospects within the reach of current interferometers.
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Akiyama, T., R. L. Boivin, M. W. Brookman, G. H. Degrandchamp, W. W. Heidbrink, C. M. Muscatello, R. I. Pinsker, K. E. Thome, B. Van Compernolle, and M. A. Van Zeeland. "Fast wave interferometer for ion density measurement on DIII-D." Journal of Instrumentation 17, no. 01 (January 1, 2022): C01052. http://dx.doi.org/10.1088/1748-0221/17/01/c01052.
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Abstract A fast wave interferometer (FWI), which can measure ion mass density, has been developed on DIII-D for its use on future fusion reactors, as well as for the study of ion behavior in current plasma devices. The frequency of the fast waves used for the FWI is around 60 MHz, and require antennas and coaxial cables or waveguides, which, unlike traditional mirror-based optical interferometers, are less susceptible to neutron/gamma-ray radiation and are relatively immune to impurity deposition and erosion as well as alignment issues. The bulk ion density evaluated using FWI show good agreement with that derived from CO2 interferometry within about 15%. When the ion mass density measurement by FWI is combined with an electron density measurement from CO2 interferometry, Z eff measurements are also enabled and are in agreement with those from visible Bremsstrahlung measurements. Additionally, large-bandwidth FWI measurements clearly resolve 10–100 kHz coherent modes and demonstrate its potential as a core fluctuation diagnostic, sensitive to both magnetic and ion density perturbations.
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Vu, Toan-Thang, Thanh-Tung Vu, Van-Doanh Tran, Thanh-Dong Nguyen, and Ngoc-Tam Bui. "A New Method to Verify the Measurement Speed and Accuracy of Frequency Modulated Interferometers." Applied Sciences 11, no. 13 (June 22, 2021): 5787. http://dx.doi.org/10.3390/app11135787.
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The measurement speed and measurement accuracy of a displacement measuring interferometer are key parameters. To verify these parameters, a fast and high-accuracy motion is required. However, the displacement induced by a mechanical actuator generates disadvantageous features, such as slow motion, hysteresis, distortion, and vibration. This paper proposes a new method for a nonmechanical high-speed motion using an electro-optic modulator (EOM). The method is based on the principle that all displacement measuring interferometers measure the phase change to calculate the displacement. This means that the EOM can be used to accurately generate phase change rather than a mechanical actuator. The proposed method is then validated by placing the EOM into an arm of a frequency modulation interferometer. By using two lock-in amplifiers, the phase change in an EOM and, hence, the corresponding virtual displacement could be measured by the interferometer. The measurement showed that the system could achieve a displacement at 20 kHz, a speed of 6.08 mm/s, and a displacement noise level < 100 pm//√Hz above 2 kHz. The proposed virtual displacement can be applied to determine both the measurement speed and accuracy of displacement measuring interferometers, such as homodyne interferometers, heterodyne interferometers, and frequency modulated interferometers.
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Petrov A.V., Chapalo I.E., Bisyarin M.A., and Kotov O.I. "Intermodal fiber interferometer based on broadband light source and optical spectrum analyzer for external perturbations measurement." Technical Physics Letters 48, no. 15 (2022): 7. http://dx.doi.org/10.21883/tpl.2022.15.53809.18968.
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An intermodal fiber interferometer based on broadband light source and spectral signal processing is proposed and experimentally investigated. The perturbation of the parameters of the spectrum analyzer (scanning range and width of the instrumental spectral response function) on the output signal is demonstrated. It is shown that the method of correlation signal processing makes it possible to obtain linear and stable response to external fiber perturbations. The proposed interferometer scheme can be prospective for development of real-time sensors of physical quantities. Keywords: intermodal fiber interferometer, fiber-optic sensors, fiber optics, multimode fiber, interferometers.
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de Haan, Victor. "Mach–Zehnder fiber interferometer test of the anisotropy of the speed of light." Canadian Journal of Physics 87, no. 9 (September 2009): 999–1008. http://dx.doi.org/10.1139/p09-062.
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Two optical fiber Mach–Zehnder interferometers were constructed in an environment with a temperature stabilization of better than 1 mK per day. One interferometer consisted of a length of 12 m optical fiber in each arm, with the main direction of the arms perpendicular to each other while the other consisted of a length of 2 m optical fiber in each arm, where the main direction of the arms are parallel, and served as a control. In each arm, 1 m of fiber was wound around a ring made of piezo material, enabling the control of the length of the arms by means of an applied voltage. The influence of the temperature on the optical phase difference between the interferometer arms was measured. The temperature change induced a variation of the interaction region of the optical fiber couplers. Further, the influence of rotation of the interferometers at the Earth surface on the observed phase differences was determined. For one interferometer (with the long and perpendicular arms), it was found that the phase difference depends on the azimuth of the interferometer. For the other one (with the short and parallel arms), no relevant dependence on the azimuth has been measured.
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Shyu, Lih Horng, Yung Cheng Wang, and Jui Cheng Lin. "A Compact Signal Processing with Position Sensitive Detectors Utilized for Michelson Interferometer." Key Engineering Materials 437 (May 2010): 98–102. http://dx.doi.org/10.4028/www.scientific.net/kem.437.98.
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Interferometric signals of a homodyne Michelson interferometer appear in sinusoidal forms. In this investigation, new concepts for signal processing of Michelson interferometer are demonstrated. With the utilization of detection of position sensitive detector (PSD) and by the procedure of differential signals and the characteristic of symmetric waveform, a compact signal processing for homodyne Michelson interferometer has been developed. Its advantages include simplified procedure, fast processing and few electronic hardware. For experiment tests of the signal processing, a conventional homodyne Michelson interferometer has been constructed. Major components of the interferometer consist of laser light source, beam splitter, mirrors, PSD and piezo transducer for driving measurement mirror. To verify the performance of the signal processing, a commercial nanopositioning stage as reference standard has been utilized for comparison measurements. Through theoretical analysis and experiment tests, it can be proved that by the developed signal processing an interferometer possesses the optical resolution of 79 nm. With support of the developed signal processing, interferometers will possess the benefits of simply structure, few components and lower cost.