Relevant bibliographies by topics / Ultrafast Pulse

Academic literature on the topic 'Ultrafast Pulse'

Author: Grafiati
Published: 25 May 2024

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Contents

Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Ultrafast Pulse.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Journal articles on the topic "Ultrafast Pulse"

1

Liu, Yongshan, Houyi Cheng, Pierre Vallobra, Huiwen Wang, Sylvain Eimer, Xiaoqiang Zhang, Gregory Malinowski, et al. "Ultrafast single-pulse switching of Tb-dominant CoTb alloy." Applied Physics Letters 122, no. 2 (January 9, 2023): 022401. http://dx.doi.org/10.1063/5.0131716.

Full text
Abstract:
Single-pulse magnetization switching by femtosecond laser pulses is the fastest way to manipulate magnetization. To date, among rare-earth transition metal alloys, single-pulse switching is limited to Gd-based structures. Here, we demonstrate ultrafast single-pulse switching of Tb-dominant CoTb alloys within several tens of picoseconds. Our further analysis shows that the ultrafast magnetization reversal is linked to ultrafast heating of laser pulses and an external field.
APA, Harvard, Vancouver, ISO, and other styles
2

Garming, Mathijs W. H., Pieter Kruit, and Jacob P. Hoogenboom. "Imaging resonant micro-cantilever movement with ultrafast scanning electron microscopy." Review of Scientific Instruments 93, no. 9 (September 1, 2022): 093702. http://dx.doi.org/10.1063/5.0089086.

Full text
Abstract:
Here, we demonstrate ultrafast scanning electron microscopy (SEM) for making ultrafast movies of mechanical oscillators at resonance with nanoscale spatiotemporal resolution. Locking the laser excitation pulse sequence to the electron probe pulses allows for video framerates over 50 MHz, well above the detector bandwidth, while maintaining the electron beam resolution and depth of focus. The pulsed laser excitation is tuned to the oscillator resonance with a pulse frequency modulation scheme. We use an atomic force microscope cantilever as a model resonator, for which we show ultrafast real-space imaging of the first and even the 2 MHz second harmonic oscillation as well as verification of power and frequency response via the ultrafast movies series. We detect oscillation amplitudes as small as 20 nm and as large as 9 μm. Our implementation of ultrafast SEM for visualizing nanoscale oscillatory dynamics adds temporal resolution to the domain of SEM, providing new avenues for the characterization and development of devices based on micro- and nanoscale resonant motion.
APA, Harvard, Vancouver, ISO, and other styles
3

Zeng, Li, Xiaofan Wang, Yifan Liang, Huaiqian Yi, Weiqing Zhang, and Xueming Yang. "Chirped-Pulse Amplification in an Echo-Enabled Harmonic-Generation Free-Electron Laser." Applied Sciences 13, no. 18 (September 14, 2023): 10292. http://dx.doi.org/10.3390/app131810292.

Full text
Abstract:
The field of ultrafast science has experienced significant growth over the last decade, largely attributed to advancements in optical and laser technologies such as chirped-pulse amplification and high-harmonic generation. The distinctive characteristics of intense ultrafast free-electron lasers (FELs) have introduced novel prospects for investigating molecular dynamics, as well as providing an opportunity to gain deeper insights into nonlinear processes in materials. Therefore, high-power ultrafast FELs can be widely used for both fundamental research and practical applications. This study presents a novel approach for producing high-power femtosecond FEL pulses, utilizing chirped-pulse amplification in echo-enabled harmonic generation. Chirped seed pulses are employed to induce frequency-chirped energy modulation in the electron beam. The generated FEL pulse, which inherits the chirped frequency, can be compressed through the gratings in the off-plane mount geometry to provide ultraintense ultrafast pulses. The numerical modeling results indicate that peak power exceeding 20 GW and a pulse duration in the order of several femtoseconds can be achieved.
APA, Harvard, Vancouver, ISO, and other styles
4

Xu, Hantao, Baiyu Liu, Yongsheng Gou, Jinshou Tian, Yang Yang, Penghui Feng, Xu Wang, and Shiduo Wei. "Research on Triode Based High Re−Frequency Ultrafast Electrical Pulse Generation Technology." Electronics 12, no. 8 (April 21, 2023): 1950. http://dx.doi.org/10.3390/electronics12081950.

Full text
Abstract:
The high−repeat frequency ultrafast electrical pulse generation technology is mainly based on ultrafast switching devices combined with ultrafast circuits to generate electrical pulses with repetition frequencies of several kilohertz and a rise−time of nanoseconds or even picoseconds. This technology is the basis for several research studies and is one of the key technologies that has received wide attention from various countries. The problems to be solved are high re−frequency ultrafast high−voltage pulse generation and ultra−broadband ultrafast pulse transport and circuit stability applicability, which include circuit conduction mechanism research, pulse generation time improvement and recovery time reduction. By studying the avalanche transistor high−voltage transient conduction characteristics and reducing the loss in the carrier transport process, the influence of each parameter on the output is determined, and the key factors to enhance the circuit performance are identified. This paper designs a new high−repetition frequency ultrafast electric pulse generation (UPG) circuit using pure electronics components, which consists of combining avalanche transistor model 2N2222 with a hybrid Marx structure at the same time in the pulse circuit to add filtering, fast recovery diodes and pulse cutoff and other matching techniques to make its output more stable, which can obtain higher output frequency, faster rise−time and narrower pulse widths. It has been tested that a high re−frequency ultrafast high−voltage electrical pulse signal with a pulse repetition frequency of 200 kHz, a leading edge of 800 ps, a half−high pulse width of 5 ns, an amplitude of 1.2 kV and jitter of less than 5% can be generated at the load with a 50 Ω load at the output. The signal can be applied in the fields of ultrafast diagnosis, information countermeasures and nuclear electromagnetic radiation research.
APA, Harvard, Vancouver, ISO, and other styles
5

Tang, Ziwen, Zihua Zheng, Boyao Li, Zhiyi Wei, and Jinghua Sun. "Applications of Microstructured Optical Fibers in Ultrafast Optics: A Review." Photonics 11, no. 2 (February 5, 2024): 151. http://dx.doi.org/10.3390/photonics11020151.

Full text
Abstract:
With the development of laser technology, microstructured optical fibers (MOFs) have become an important part of ultrafast optics, providing excellent platforms for ultrafast laser pulse generation, amplification, and compression, promoting the development of fiber laser systems to generate high power, high pulse energy, and few-cycle duration pulses. MOFs extend the ultrafast laser spectrum to the vacuum ultraviolet (VUV) and even extreme ultraviolet (EUV) regions based on dispersive wave emission and high harmonic generation, as well as to the mid-infrared region based on soliton self-frequency shift (SSFS), contributing compact and low-cost light sources for precision microscopy and spectroscopy. In this paper, first several common types of MOFs are introduced, then the various applications of MOFs in ultrafast optics are discussed, mainly focusing on the aspects of ultrafast laser pulse scaling in pulse energy and spectral bandwidth, and finally the possible prospects of MOFs are given.
APA, Harvard, Vancouver, ISO, and other styles
6

Wei, Xianqi, Xiaoli Wang, Xin Li, and Weihua Liu. "Electronic Pulses from Pulsed Field Emission of CNT Cathodes." Journal of Nanomaterials 2018 (2018): 1–6. http://dx.doi.org/10.1155/2018/4396430.

Full text
Abstract:
We presented a demonstration of infrared laser irradiated field emission electronic pulse based on carbon nanotube (CNT) cathodes. Electronic pulses greatly depended on pulsed infrared laser and were almost synchronous with laser pulses. We have designed a pulsed field emission cathode based on CNTs and investigated correlation between electronic pulse and laser pulse, acquiring the shortest width of electronic pulses about 50 ms and turn-on field less than 0.14 V/μm. Besides, we have studied the thermal effect on the pulsed field emission of CNT cathodes caused by laser heating. Interestingly, the thermal effect has caused an enhancement of emission current but resulted in a waveform distortion on short electronic pulses. The application of laser pulses on CNT cathodes would extend conventional electron sources to a pulsed electron source and offered a possibility of pulsed field emission. These results were encouraging us to prepare further studies of ultrafast electronic pulses for high-frequency electron sources.
APA, Harvard, Vancouver, ISO, and other styles
7

Lyu, Wenhao, Yuan Cheng, Jiayi An, Marcello Condorelli, Mario Pulvirenti, Giuseppe Compagnini, Xiaogang Wang, Bo Fu, and Vittorio Scardaci. "Silver Nanoplate Composites as Nonlinear Saturable Absorbers for a Q-Switched Laser." Photonics 9, no. 11 (November 7, 2022): 835. http://dx.doi.org/10.3390/photonics9110835.

Full text
Abstract:
Metal nanomaterials have promising applications in ultrafast photonics due to their broadband operation, large third-order nonlinear susceptibility, and ultrafast recovery time. We realized a Q-switched pulsed erbium-doped fiber laser based on a silver nanoplate polyvinyl alcohol film as a saturable absorber. This film, with a modulation depth of 15.7%, was integrated into a fiber laser by means of a sandwich structure. We obtained Q-switched pulses in the 1.5-μm band, which plays an important role in telecommunications and atmospheric detection. Stable Q-switched pulses were obtained at the pump power of 135 mW, with a single pulse energy of 33.8 nJ, a pulse width of 2.3 μs, a repetition rate of 62.4 kHz, and a signal-to-noise ratio of about 45 dB. When increasing the pump power up to a maximum value of 246 mW, the maximum single pulse energy of 57.8 nJ was achieved. This study first demonstrates the potential of silver nanoplates as saturable absorbers in generating stable laser pulses with high energy.
APA, Harvard, Vancouver, ISO, and other styles
8

Cai, Houzhi, Kaixuan Lin, Qiuyan Luo, Dong Wang, Junkun Huang, Kangjing Xu, Longjie Luo, and Jinyuan Liu. "Two-Dimensional Ultrafast X-ray Imager for Inertial Confinement Fusion Diagnosis." Photonics 9, no. 5 (April 22, 2022): 287. http://dx.doi.org/10.3390/photonics9050287.

Full text
Abstract:
A two-dimensional ultrafast X-ray imager (UXI) composed of a time-dilation device, an electron-beam imaging unit, a gated microchannel plate (MCP) framing tube, and a pulser was developed. The time-dilation device extends the time spread of the electron signal generated by the pulsed photocathode (PC), and the electron-beam imaging unit images the electron pulse from PC to MCP. Finally, the gated MCP framing tube samples the dilated electron pulse. The time resolution and image size of the UXI were measured with an X-ray generated by a terawatt laser targeting device. When a driving pulse with a 2 V/ps slope is applied to the PC, the measured time resolution is 21 ps, and the image size is 12 mm × 3.9 mm. Furthermore, the image size varies with the time resolution. The results show that as the time resolution improves, the image size decreases. The use of two opposite-transmission PC driving pulses could improve the image size. Moreover, the measured UXI spatial resolution is 5 lp/mm, and the spatial resolution will be worse with the increasing off-axis distance.
APA, Harvard, Vancouver, ISO, and other styles
9

Yang, Jinfeng, Takafumi Kondoh, Koichi Kan, and Yoichi Yoshida. "Ultrafast pulse radiolysis." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 629, no. 1 (February 2011): 6–10. http://dx.doi.org/10.1016/j.nima.2010.11.109.

Full text
APA, Harvard, Vancouver, ISO, and other styles
10

Horiuchi, Noriaki. "Ultrafast pulse switching." Nature Photonics 11, no. 6 (June 2017): 331. http://dx.doi.org/10.1038/nphoton.2017.88.

Full text
APA, Harvard, Vancouver, ISO, and other styles
More sources

Dissertations / Theses on the topic "Ultrafast Pulse"

1

Chauhan, Vikrant Chauhan Kumar. "Pulse compression and dispersion control in ultrafast optics." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/37153.

Full text
Abstract:
Pulse Compression and Dispersion Control in Ultrafast Optics Vikrant K. Chauhan 116 Pages Directed by Dr. Rick P. Trebino In this thesis, we introduced novel pulse compressors that are easy to align and which also compensate for higher order dispersion terms. They use a single dispersive element or a combination of dispersive elements in single-element-geometry. They solve the problem of extra-cavity pulse compression by providing control of the pulse width in almost all of the experiments performed using ultrashort pulses, and they even compensate for higher order dispersion. We performed full spatiotemporal characterization of these compressors and demonstrated their performance. We also developed a theoretical simulation of pulse compressors which is based on a matrix based formalism. It models the full spatiotemporal characteristics of any dispersion control system. We also introduced a simple equation, in its most general form, to relate the total dispersion and magnification introduced by an arbitrary sequence of dispersive devices. Pulse compressor characterization was done using interferometric measurements in the experiments presented in this work, but we also developed a method to measure pulses that uses polarization gating FROG for measuring two unknown pulses. In the last part, we briefly discuss the designing of a high energy chirped pulse amplification system.
APA, Harvard, Vancouver, ISO, and other styles
2

Liu, Xuan. "Numerical Simulations of Ultrafast Pulse Measurements." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/16175.

Full text
Abstract:
This thesis contains two major components of research: numerical simulation of optical-parametric amplification cross correlation of Frequency-Resolved Optical Gating (OPA-XFROG) and numerical simulation of GRENOUILLE and its related issues. Recently, an extremely sensitive technique--OPA-XFROG has been developed. A short pump pulse serves as the gate by parametrically amplifying a short segment of the signal pulse in a nonlinear crystal. High optical parametric gain makes possible the complete measurement of ultraweak, ultrashort light pulses. Unlike interferometric methods, it does not carry prohibitively restrictive requirements, such as perfect mode-matching, perfect spatial coherence, highly stable absolute phase, and a same-spectrum reference pulse. We simulate the OPA-XFROG technique and show that by a proper choice of the nonlinear crystal and the noncollinear mixing geometry it is possible to match the group velocities of the pump, signal, and idler pulses, which permits the use of relatively thick crystals to achieve high gain without measurement distortion. Gain bandwidths of ~100 nm are possible, limited by group velocity dispersion. In the second part of the thesis, we numerically simulate the performance of the ultrasimple ultrashort laser pulse measurement device- GRENOUILLE. While simple in practice, GRENOUILLE has many theoretical subtleties because it involves the second-harmonic generation of relatively tightly focused and broadband pulses. In addition, these processes occur in a thick crystal, in which the phase-matching bandwidth is deliberately made narrow compared to the pulse bandwidth. We developed a model that include all sum-frequency-generation processes, both collinear and noncollinear. We also include dispersion using the Sellmeier equation for the crystal BBO. Working in the frequency domain, we compute the GRENOUILLE trace for practical-and impractical-examples and show that accurate measurements are easily obtained for properly designed devices. For pulses far outside a GRENOUILLE's operating range (on the long side), we numerically deconvolve the GRENOUILLE trace with the response function of GRENOUILLE to improve its spectral resolution. In the last part of the thesis, we simulate the second harmonic generation with tightly focused beams by use of lens. Thus, we are able to explain the `weird' focusing effect that has been a `puzzles' for us in the GRENOUILLE measurement.
APA, Harvard, Vancouver, ISO, and other styles
3

Wang, Feihu. "Ultrafast terahertz pulse generation from quantum cascade lasers." Electronic Thesis or Diss., Paris 6, 2016. http://www.theses.fr/2016PA066752.

Full text
Abstract:
Lasers à cascades quantiques (LCQs) THz sont des dispositifs à semi-conducteurs fondamentaux pour l'action du laser dans la gamme THz. Des évolutions considérables ont été réalisées dans la dernière décennie en termes de fonctionnement de la température et de la puissance de sortie. LCQs THz peuvent posséder de bandes spectrales très larges, les rendant approprié pour la génération d'impulsions THz ultracourtes par blocage de mode. Cependant, à ce jour, la génération d'impulsions THz de LCQ a été limitée à 10 - 20 ps, en dépit de plusieurs années d'efforts de recherche. Dans cette thèse, ce goulot d'étranglement dans la technologie QCL est étudié et surmontée. Plusieurs étapes qui ont permis la réalisation de génération d'impulsions ultracourtes de LCQ ont été réalisées. Performances de "state-of-the-art" actuelles sont représentés, à l'aide de LCQ avec une bande passante étroite dans des guides d'ondes "single-plasmon" et des impulsions THz de 20 ps sont générés à basse température (10K). Ceci est suivi par, pour la première fois, le verrouillage de modes des LCQs des bandes spectrales larges dans les guides d'onde métal-métal à des températures élevées (77k). Même avec de bandes spectrales larges, les impulsions obtenus étaient seulement 11 ps et nous montrent que la dispersion de l'indice et la modulation électrique sont les facteurs critiques. Enfin, ces effets sont compensés par un interféromètre de Gires-Tournois et un modulation de perte. Cette approche permet de générer des impulsions aussi courtes que 4 ps, avec la possibilité d'aller beaucoup plus loin dans la sous-picoseconde
THz quantum cascade lasers (QCLs) are foundational semiconductor devices for laser action in the THz range. Considerable developments have been made in the last decade in terms of temperature operation and high output power. THz QCLs can also possess extremely large spectral bandwidths, rendering them suitable for ultrashort THz pulse generation through modelocking, with pulse widths of a few picoseconds theoretically obtainable. However, to date, the generation of THz pulses from QCLs has been limited to 10 - 20 ps, despite several years of research effort. In this thesis, this bottleneck in QCL technology is investigated and overcome. Several milestones have been achieved that permitted the realization of ultrashort pulse generation from QCLs. Current state-of-the-art performances are shown, using narrow spectral bandwidth QCLs in single-plasmon waveguides, and where modelocking results in 20 ps long THz pulses at low temperatures (10K). This is followed by, for the first time, mode-locking of broad spectral bandwidth QCLs in sub-wavelength metal-metal waveguides at ‘high’ temperatures (77K). Even with large spectral bandwidths, the shortest pulses achieved were only 11 ps and we show that the index dispersion and the electrical modulation are the critical factors. Finally, these effects are compensated through a Gires-Tournois interferometer and an extra loss mechanism, respectively, integrated monolithically onto a QCL. This approach permits to generate pulses as short as 4 ps, with the potential to go considerably further to the sub-picosecond or single cycle regime
APA, Harvard, Vancouver, ISO, and other styles
4

Lee, Dongjoo. "Ultra-broadband phase-matching ultrashort-laser-pulse measurement techniques." Diss., Available online, Georgia Institute of Technology, 2007, 2007. http://etd.gatech.edu/theses/available/etd-07032007-113912/.

Full text
Abstract:
Thesis (Ph. D.)--Physics, Georgia Institute of Technology, 2008.
First, Phillip, Committee Member ; Adibi, Ali, Committee Member ; Raman, Chandra, Committee Member ; Buck, John, Committee Member ; Trebino, Rick, Committee Chair.
APA, Harvard, Vancouver, ISO, and other styles
5

Ma, Jun. "Ultrafast Electron Transfer in Solutions Studied by Picosecond Pulse Radiolysis." Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLS023/document.

Full text
Abstract:
L'interaction de particules énergétiques avec les résultats de l'eau dans l'excitation et l'ionisation des molécules d'eau. Le processus d'ionisation se rapporte à la génération de l'excès d'électrons détachés de leurs molécules parentes et laissant derrière le trou positive (notée H₂O•⁺). Cela se produit sur le calendrier d'une transition électronique ~ 10⁻¹⁵s. Les processus chimiques plus anciens de H₂O•⁺ et l'excès d'électrons vers autre question suivie de l'eau en vrac ionisants restent encore peu par rapport connu et constitue un sujet difficile dans la chimie de rayonnement. Dans ma thèse, les techniques de radiolyse d'impulsions picoseconde ont été utilisés pour observer la cinétique de la SO₄•⁻, H₂PO₄• dans de l'acide sulfurique très concentré et solutions d'acide phosphorique sur une large gamme de concentrations (de 1 mol L⁻¹ à l'acide pur). Les résultats expérimentaux montrent clairement que le radical secondaire de sulfurique (SO₄•⁻) et de l'acide phosphorique (H₂PO₄•) peuvent être formés par l'intermédiaire de deux mécanismes : détachement d'électrons direct par l'impulsion d'électrons (7 ps) et le transfert d'électrons ultra-rapide des solutés au radical cation de l'eau H₂O•⁺. La réactivité des espèces oxydantes fortes, H₂O•⁺ vers les solutés dans des solutions aqueuses très concentrées est quantitativement démontré
The interaction of energetic particles with water results in the excitation and ionization of water molecules. The ionization process refers to the generation of the excess electrons detached from their parent molecules and leaving behind the positive hole (denoted as H₂O•⁺). This occurs on the timescale of an electronic transition ~10⁻¹⁵ s. The earliest chemical processes of H₂O•⁺ and excess electron towards other matter followed water ionizing in bulk still remain relative little known and constitute a challenging subject in radiation chemistry. In my thesis, picosecond pulse radiolysis techniques were used to observe the kinetics of the SO₄•⁻, H₂PO₄• in highly concentrated sulfuric acid and phosphoric acid solutions over a large range of concentrations (from 1 mol L⁻¹ to neat acid). The experimental results showed clearly that the secondary radical of sulfuric (SO₄•⁻) and phosphoric acid (H₂PO₄•) can be formed via two mechanisms: direct electron detachment by the electron pulse (7 ps) and ultrafast electron transfer from the solutes to the radical cation of water H₂O•⁺. The reactivity of the strongest oxidizing species, H₂O•⁺ towards the solutes in highly concentrated aqueous solutions is quantitatively demonstrated
APA, Harvard, Vancouver, ISO, and other styles
6

Lamour, Tobias Paul. "High pulse energy near-infrared ultrafast optical parametric oscillators." Thesis, Heriot-Watt University, 2011. http://hdl.handle.net/10399/2509.

Full text
Abstract:
A source-demand in the near- and mid-IR wavelength spectrum exists for various applications such as waveguide inscription, multiphoton imaging, and nonlinear spectroscopy. All of the applications seek for higher repetitions rates for faster processing speed, better signal to noise ratios or to improve the results for applications like laser waveguide inscription. This is in contrast to the high pulse energies, required to drive the nonlinear processes involved with these applications. Available systems are either based on low-energy, high-repetition-rate optical parametric oscillators or high-energy, low-repetition-rate optical parametric amplifiers. In this thesis a sources was developed that can bridge the wide gap between these two extremes, providing sufficient energy to drive nonlinear processes, with repetition rates in the MHz domain. This was achieved by introducing three techniques previously employed for energy scaling in laser cavities. Firstly an exchange from the conventionally used Ti:sapphire pump to a commercial high power Yb:fibre laser system readily scaled the usable pump energy. This was combined with a technique known as cavity-length extension, which allows a lowering of the cavity roundtrip time offering the build-up of pulses with increased energy. In a final stage, cavity-dumping on basis of an acousto-optic modulator was introduced into the a redesigned cavity. The combination of these three techniques, novel to synchronously pumped optical parametric oscillators, enabled the extraction of record-high pulse energies and peak powers
APA, Harvard, Vancouver, ISO, and other styles
7

Shimotsuma, Yasuhiko. "Nano-modification of transparent materials using ultrafast pulse laser." 京都大学 (Kyoto University), 2005. http://hdl.handle.net/2433/144535.

Full text
APA, Harvard, Vancouver, ISO, and other styles
8

Benane, Mehdi Yanis. "Ultrafast, broadband and multi-pulse transmissions for ultrasonic imaging." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1268/document.

Full text
Abstract:
L'échographie est un outil de diagnostic largement utilisé grâce à des vertus telles que l'acquisition / traitement de données en temps réel, la facilité d'utilisation et la sécurité pour le patient / praticien pendant l'examen. Cependant, comparée à d'autres méthodes d'imagerie telles que la tomographie à rayons X et l'imagerie par résonance magnétique, l'échographie présente l'inconvénient de fournir une qualité d'image relativement basse. Dans cette thèse, nous étudions une méthode capable d'augmenter la qualité d'image, permettant ainsi de meilleurs diagnostics échographiques. Afin d'augmenter le rapport signal / bruit des signaux reçus, nous proposons d'utiliser des signaux modulés en fréquence (chirps). Pour éviter l'effet négatif de la bande passante limitée de la sonde, nous modulons en amplitude les signaux d'excitations afin d'augmenter l'énergie du signal dans les bandes de fréquences où la sonde est moins efficace. Pour compresser l'énergie des échos, nous utilisons des filtres de Wiener afin d'obtenir un bon compromis résolution spatiale / stabilité du bruit. Nous combinons cette méthode appelée REC (Resolution Enhancement Technique) avec l’imagerie ultrarapide. Nous montrons des résultats simulés et expérimentaux (in-vitro, ex-vivo et in-vivo) prometteurs. De plus, nous adaptons REC afin de compenser l'effet d'atténuation tissulaire. Cette amélioration est validée expérimentalement sur des phantoms. Nous adaptons également REC à la propagation non linéaire des ondes ultrasonores, en proposant une technique d'inversion d'impulsions qui utilise REC pour fournir une meilleure résolution et un meilleur rapport contraste / bruit. Ensuite, nous appliquons REC à différents schémas d’acquisition tels que les ondes divergentes et la transmission multi-lignes (MLT). Nous montrons également que la qualité d’image peut être augmentée davantage en tenant compte de la réponse impulsionnelle spatiale de la sonde lorsque REC et MLT sont combinés
Ultrasound imaging is a diagnostic tool widely used thanks to such virtues as real-time data acquisition / processing, ease of use and safety for the patient / practitioner during examination. However, when compared to other imaging methods such as X-ray tomography and Magnetic Resonance Imaging, the echography has the disadvantage to provide relatively low image quality. In this thesis, we study a method that is able to increase the ultrasound image quality, thus paving the way towards improved diagnostics based on echography and novel ultrasound applications. In order to increase the echo signal to noise ratio of the received signals, we propose to use linear frequency modulated signals, also called chirps. To avoid the negative effect of the bandlimited acquisition probe, we apply a pre-enhancement step on the probe excitation signals in order to boost the signal energy in the frequency bands where the probe is less efficient. To compress the echo energy in reception, we use Wiener filters that allow obtaining a good trade-off between the spatial resolution and noise stability. We apply the previously detailed pipeline, also called REC (Resolution Enhancement Technique) on ultrafast imaging schemes. We show promising results in simulation and in-vitro, ex-vivo, in-vivo acquisitions. Furthermore, we adapt REC in such way that the frequency dependent tissue attenuation effect is compensated for. This improvement is validated in simulation and phantom experiments. We also adapt REC to the nonlinear propagation of ultrasound waves, by proposing a pulse inversion technique that uses REC to provide a better image resolution and contrast to noise ratio. Then, we demonstrate the generality of the REC method by applying it to different acquisition schemes such as diverging wave compounding and Multi Line Transmit (MLT). We also show that the image quality can be increased more by taking into account the spatial impulse response of the ultrasound probe when REC and MLT are combined
APA, Harvard, Vancouver, ISO, and other styles
9

Akturk, Selcuk. "Extending ultrashort-laser-pulse measurement techniques to new dimensions, time scales, and frequencies." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/6892.

Full text
Abstract:
In the last decade, there has been tremendous progress in the field of ultrashort-pulse measurement. However, this effort has focused mostly on the temporal behavior of 100-fs, 800-nm ultrashort pulse, ignoring other pulse lengths, wavelengths, and the very common space-time couplings or so called spatio-temporal distortions. In this thesis work, I do an extensive study of spatio-temporal distortions and their measurement using Frequency Resolved Optical Gating (FROG) and its relatives. I clarify some ambiguities in the descriptions of these effects in the existing theory and establish a more general description of such distortions in ultrashort pulses. I also extend these measurement techniques to different wavelengths and pulse lengths. Specifically, I develop measurement devices for few-cycle NIR pulses, weak and narrowband fiber laser pulses, long (several-ps) NIR pulses, and visible pulses from NOPAs.
APA, Harvard, Vancouver, ISO, and other styles
10

Timilsina, Pratap. "Development of an electron time of flight spectrometer for ultrafast pulse characterization and ultrafast dynamics studies." Kansas State University, 2016. http://hdl.handle.net/2097/32598.

Full text
Abstract:
Master of Science
Department of Physics
Carlos Trallero
This report presents the details of an electron time-of-flight (ETOF) spectrometer to be used for characterizing ultrafast electric field pulses. The pulses will range in pulse-duration from femtosecond to attoseconds and in wavelength from the far infrared (FIR) to the extreme ultra violet (XUV). By measuring the photoelectrons in the presence of two electric fields and their quantum interference we will be able to extract the amplitude and phase of the electric field. For XUV pulses this is the well-known streaking and Reconstruction of Attosecond Beating by Interference of Two-Photon Transition (RABITT) method. The ETOF is based on a set of tunable electrostatic lenses capable of detecting 0-150 eV electrons. In addition, we can selectively increase the photoelectron yield of the spectrum. The precise tuning of the electrostatic lens system is done with a Genetic Algorithm (GA) with an intensity fluctuation discriminator in the fitness.
APA, Harvard, Vancouver, ISO, and other styles
More sources

Books on the topic "Ultrafast Pulse"

1

America, Optical Society of, ed. Ultrafast electronics and optoelectronics: Postconference digest. Washington, DC: Optical Society of America, 2003.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
2

Topical Meeting on Ultrafast Electronics and Optoelectronics (1999 Snowmass, Colo.). Ultrafast electronics and optoelectronics: From the Topical Meeting on Ultrafast Electronics and Optoelectronics, April 14-16, 1999, Snowmass, Colorado. Washington, DC: Optical Society of America, 1999.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
3

Lasers and Electro-optics Society (Institute of Electrical and Electronics Engineers), IEEE Electron Devices Society, and Denshi Jōhō Tsūshin Gakkai (Japan), eds. Ultrafast electronics and optoelectronics: Technical digest, March 17-19, 1997, Hyatt Regency Lake Tahoe, Incline Village, Nevada. Washington, DC: Optical Society of America, 1997.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
4

1957-, Gosnell Timothy R., and Society of Photo-optical Instrumentation Engineers., eds. Ultrafast pulse generation and spectroscopy: 18-19, 22 January 1993, Los Angeles, California. Bellingham, Wash., USA: SPIE, 1993.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
5

Shuntaro, Watanabe, and Midorikawa Katsumi, eds. Ultrafast optics V. New York: Springer, 2004.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
6

Ultrafast optics. Hoboken, N.J: Wiley, 2009.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
7

Thon, Tsen Kong, ed. Ultrafast physical processes in semiconductors. San Diego: Academic Press, 2001.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
8

Krausz, Ferenc. Ultrafast Optics IV: Selected Contributions to the 4th International Conference on Ultrafast Optics, Vienna, Austria. New York, NY: Springer New York, 2004.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
9

1957-, Gosnell Timothy R., and Taylor Antoinette J. 1956-, eds. Selected papers on ultrafast laser technology. Bellingham, Wash., USA: SPIE Optical Engineering Press, 1991.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
10

Orazio, Svelto, De Silvestri Sandro, Denardo G. 1935-, and International Symposium on Ultrafast Processes in Spectroscopy (9th : 1995 : Trieste, Italy), eds. Ultrafast processes in spectroscopy. New York: Plenum Press, 1996.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
More sources

Book chapters on the topic "Ultrafast Pulse"

1

Keller, Ursula. "Linear Pulse Propagation." In Ultrafast Lasers, 25–71. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-82532-4_2.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Keller, Ursula. "Pulse Duration Measurements." In Ultrafast Lasers, 547–87. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-82532-4_10.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Keller, Ursula. "Nonlinear Pulse Propagation." In Ultrafast Lasers, 131–83. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-82532-4_4.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Wiederrecht, G. P., W. Wang, K. A. Nelson, A. M. Weiner, and D. E. Leaird. "Multiple Excitation Pulse, Multiple Probe Pulse Femtosecond Spectroscopy." In Ultrafast Phenomena VIII, 110–12. Berlin, Heidelberg: Springer Berlin Heidelberg, 1993. http://dx.doi.org/10.1007/978-3-642-84910-7_28.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Kolner, B. H. "Active Pulse Compression." In Ultrafast Phenomena VI, 47–49. Berlin, Heidelberg: Springer Berlin Heidelberg, 1988. http://dx.doi.org/10.1007/978-3-642-83644-2_14.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Harten, P. A., A. Knorr, S. G. Lee, R. Jin, F. Brown de Colstoun, E. M. Wright, G. Khitrova, H. M. Gibbs, S. W. Koch, and N. Peyghambarian. "Coherent Pulse Breakup in Femtosecond Pulse Propagation in Semiconductors." In Ultrafast Phenomena VIII, 458–59. Berlin, Heidelberg: Springer Berlin Heidelberg, 1993. http://dx.doi.org/10.1007/978-3-642-84910-7_147.

Full text
APA, Harvard, Vancouver, ISO, and other styles
7

O’Shea, Patrick, Mark Kimmel, Xun Gu, and Rick Trebino. "Highly SimplifiedUltrashort Pulse Measurement." In Ultrafast Phenomena XII, 123–25. Berlin, Heidelberg: Springer Berlin Heidelberg, 2001. http://dx.doi.org/10.1007/978-3-642-56546-5_34.

Full text
APA, Harvard, Vancouver, ISO, and other styles
8

Jovanovic, Igor, and C. P. J. Barty. "Hybrid Chirped Pulse Amplification." In Ultrafast Phenomena XIII, 125–27. Berlin, Heidelberg: Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/978-3-642-59319-2_38.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Lilienfein, Nikolai, Simon Holzberger, and Ioachim Pupeza. "Ultrafast Optomechanical Pulse Picking." In Exploring the World with the Laser, 371–87. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-64346-5_21.

Full text
APA, Harvard, Vancouver, ISO, and other styles
10

Liu, Zhenlin, Toshimasa Kozeki, Yuji Suzuki, Nobuhiko Sarukura, Kiyoshi Shimamura, Tsuguo Fukuda, Masahiro Hirano, and Hideo Hosono. "Chirped pulse amplification for ultraviolet femtosecond pulses using Ce:LiCAF crystal." In Ultrafast Phenomena XII, 99–101. Berlin, Heidelberg: Springer Berlin Heidelberg, 2001. http://dx.doi.org/10.1007/978-3-642-56546-5_27.

Full text
APA, Harvard, Vancouver, ISO, and other styles

Conference papers on the topic "Ultrafast Pulse"

1

Chambaret, J. P., G. Chériaux, P. Rousseau, and F. Salin. "On the pulse quality limitations in ultrashort chirped pulse amplification." In International Conference on Ultrafast Phenomena. Washington, D.C.: Optica Publishing Group, 1996. http://dx.doi.org/10.1364/up.1996.tue.3.

Full text
Abstract:
Recent progress in the understanding of the physics of femtosecond oscillators has made it possible to produce 10 fs pulses. In order to use these pulses in high field physics experiments they have to be amplified while keeping an extremely good contrast ratio between the peak of the pulse and its wings. We will show that several effects can cause a severe loss in the pulse quality and will present new solutions.
APA, Harvard, Vancouver, ISO, and other styles
2

Seggebruch, Michael W. L., and Christopher P. J. Barty. "Synthesis of Multi-GHz Ultrafast Pulse Trains via Harmonic Bandwidth Broadening of Electro-Optic Frequency Combs." In Ultrafast Optics. Washington, D.C.: Optica Publishing Group, 2023. http://dx.doi.org/10.1364/ufo.2023.p2.3.

Full text
Abstract:
Relative to a standard electro-optic frequency comb (EOFC) generating architecture, we present ~2-4x shorter ultrafast pulses and ~7x less pulse duration variation across a 6-15 GHz repetition rate range via Harmonic Bandwidth Broadening, i.e. the generation of EOFCs with harmonics of the intended repetition rates and subsequent pulse picking.
APA, Harvard, Vancouver, ISO, and other styles
3

Squier, J. A., T. Guo, C. LeBlanc, G. Korn, C. Rose-Petruck, F. Raksi, V. V. Yakovlev, K. Yamakawa, and C. P. J. Barty. "Regenerative pulse shaping: a new technique for ultrabroadband amplification." In International Conference on Ultrafast Phenomena. Washington, D.C.: Optica Publishing Group, 1996. http://dx.doi.org/10.1364/up.1996.tue.1.

Full text
Abstract:
Traditionally, pulse shaping of femtosecond pulses is accomplished by first dispersing the pulse using a grating, and modulating the spatially chirped beam at the transform plane of an imaging system. In this paper we introduce regenerative, intra-cavity pulse shaping of chirped pulses. This method has inherent advantages over traditional pulse shaping techniques for producing certain types of pulse shapes, and overcoming limiting processes such as gain narrowing. Using regenerative pulse shaping we demonstrate for the first time 1) amplification beyond the gain narrowing limit, 2) simultaneous amplification of two ~100-fs pulses separated in wavelength by as much as 100 nm, and finally, 3) difference frequency mixing of these two amplified pulses to produce tunable mid-IR (6-12 μm) ultrashort pulses.
APA, Harvard, Vancouver, ISO, and other styles
4

Zhou, Jianping, Chung-Po Huang, Henry C. Kapteyn, and Margaret M. Murnane. "Ultrashort-Pulse Amplification in Ti:sapphire." In International Conference on Ultrafast Phenomena. Washington, D.C.: Optica Publishing Group, 1994. http://dx.doi.org/10.1364/up.1994.wb.4.

Full text
Abstract:
The extremely broad gain bandwidth of Ti:sapphire has made this material one of the most promising for the generation of ultrashort optical pulses.1 Recent advances in ultrashort-pulse Ti:sapphire lasers have made it possible to routinely generate optical pulses of ~10 fs in duration, with nJ energies.2-5 However, many applications of ultrashort pulses such as ultrafast x-ray generation, short-wavelength lasers, XUV harmonic generation, and multi-photon ionization require higher energies, and therefore it is of great interest to amplify the low energy pulses from the laser to higher energies, while maintaining their ultrashort duration. Recently we have demonstrated the generation of 0.5 mJ, 21 fs pulses, with a near-transform limited bandwidth of 44 nm, from our amplifier system.6,7 in this paper, we present preliminary results from a second stage of amplification, which demonstrate pulse energies of up to 45 mJ, with spectral bandwidths of 37 nm. This bandwidth corresponds to a pulse duration of less than 30 fs.
APA, Harvard, Vancouver, ISO, and other styles
5

Strickland, D., P. Maine, M. Bouvier, S. Williamson, and G. Mourou. "Picosecond Pulse Amplification Using Pulse Compression Techniques." In International Conference on Ultrafast Phenomena. Washington, D.C.: Optica Publishing Group, 1986. http://dx.doi.org/10.1364/up.1986.tub1.

Full text
Abstract:
Nd:Glass amplifiers have very good energy storage capabilities, but, the energy extraction is extremely inefficient for short pulse amplification. Scientists working in the radar field overcame similar peak power limitations by first chirping and stretching the pulse prior to amplification.1-2 By amplifying the longer pulses, much higher energies could be achieved. The echo was then compressed to a pulsewidth approximately equal to 1/Δf, where Δf is the total frequency chirp.
APA, Harvard, Vancouver, ISO, and other styles
6

Tien, A. C., X. Liu, and G. Mourou. "UV pulse assisted ultrashort laser pulse induced breakdown in fused silica." In International Conference on Ultrafast Phenomena. Washington, D.C.: Optica Publishing Group, 1996. http://dx.doi.org/10.1364/up.1996.fe.38.

Full text
Abstract:
Laser induced breakdown by ultrashort pulses in optically transparent materials has become increasingly interesting. As has been shown[1], avalanche ionization is the dominant mechanism for laser induced breakdown in such materials for pulsewidth down to ~ 100 fs, and multiphoton ionization is responsible for the initial electron generation. The breakdown threshold for the avalanche process is a function of the initial free electron density n0. By controlling the initial seed electron density, one may vary the breakdown threshold value. We have performed a pump-probe experiment on fused silica (SiO2) to test this hypothesis. A UV “pump” pulse, illuminating the same location, generates seed electrons for the later-arrived IR pulse by two-photon absorption. By varying the delay between the two pulses so that the UV pulse arrives before and after the IR pulse, we can observe the difference in the breakdown thresholds.
APA, Harvard, Vancouver, ISO, and other styles
7

Nelson, L. E., S. B. Fleischer, E. P. Ippen, and H. A. Haus. "High-power and Frequency-doubled Stretched-Pulse Fiber Laser." In International Conference on Ultrafast Phenomena. Washington, D.C.: Optica Publishing Group, 1996. http://dx.doi.org/10.1364/up.1996.tua.4.

Full text
Abstract:
Stretched-pulse additive-pulse mode-locked (SP-APM) fiber lasers generate ultra-short pulses (100 fsec) with energies comparable to those of color-center lasers [1]. By using the APM rejection port as the output port, pulse energies of over 2 nJ have been achieved with average powers of > 90 mW [2]. Here we report that frequency-doubling of these pulses results in high conversion efficiencies and transform-limited pulses of up to 200 pJ at 775 nm. When operating the SP-APM laser to optimize the frequency-doubled power, the fundamental pulses tend to have excess energy in the pulse wings and larger time-bandwidth products than when the SP-APM laser is optimized for fundamental pulse width. In order to better characterize both the fundamental and frequency-doubled pulses, we used frequency-resolved optical gating (FROG) which allows the direct determination of the intensity and phase of an ultrashort pulse [3,4]. Results indicate that the frequency-doubled SP-APM laser is a possible, inexpensive and compact, replacement for the argon-pumped Ti:Sapphire laser as a seeding source for regenerative amplifiers.
APA, Harvard, Vancouver, ISO, and other styles
8

Yamashita, Mikio, Kenji Torizuka, and Takafumi Uemiya. "Observation of Induced Phase Modulation of Femtosecond Pulses in Glass and Organic Fibers." In International Conference on Ultrafast Phenomena. Washington, D.C.: Optica Publishing Group, 1990. http://dx.doi.org/10.1364/up.1990.wc20.

Full text
Abstract:
Since spectral broadening of a weak, picosecond pulse was observed due to phase-modulation induced (IPM) by another pulse1) picosecond and femtosecond pulse compressions using IPM were proposed and analyzed2-4). However, IPM phenomena in the femtosecond time-region are not at all made clear experimentally. In this paper we present the experimental studies on IPM for femtosecond pulses propagating in a quartz glass fiber and a DAN crystal fiber.
APA, Harvard, Vancouver, ISO, and other styles
9

Witting, Tobias, Mikhail Osolodkov, Sebastián Dávila Lara, Marc J. J. Vrakking, and Federico J. Furch. "Post-compression of high power, high repetition rate OPCPA pulses in a multipass cell." In Ultrafast Optics. Washington, D.C.: Optica Publishing Group, 2023. http://dx.doi.org/10.1364/ufo.2023.f3.5.

Full text
Abstract:
We report pulse compression of sub-10 fs 800 nm pulses and pulse energies of up to 190 µJ at 100 kHz repetition rate delivered by an OPCPA system by spectral broadening in a compact multipass cell setup with a quartz plate as nonlinear medium. Compression to sub-4 fs is demonstrated.
APA, Harvard, Vancouver, ISO, and other styles
10

Hamrouni, M., A. Hwang, M. Jankowski, N. Jornod, J. Mishra, H. S. Stokowski, T. P. McKenna, et al. "Efficient and broadband mid-infrared source based on optical parametric amplification in dispersion-engineered thin film Lithium Niobate." In Ultrafast Optics. Washington, D.C.: Optica Publishing Group, 2023. http://dx.doi.org/10.1364/ufo.2023.tu3.2.

Full text
Abstract:
We report on a novel approach for efficient and broadband mid-infrared generation at the picojoule level of pump pulse energies. Driving OPA in thin-film-lithium-niobate waveguides with sub-10-pJ on-chip pump pulse energies, we demonstrate 1.5-pJ idler pulses with 150 µW average power within a 140-nm broad spectrum centered at 3200 nm.
APA, Harvard, Vancouver, ISO, and other styles

Reports on the topic "Ultrafast Pulse"

1

Kaertner, F. X., and D. Kielpinski. Laser Cooling With Ultrafast Pulse Trains. Fort Belvoir, VA: Defense Technical Information Center, September 2005. http://dx.doi.org/10.21236/ada442315.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Kielpinski, David. Laser Cooling with Ultrafast Pulse Trains. Fort Belvoir, VA: Defense Technical Information Center, July 2010. http://dx.doi.org/10.21236/ada524694.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Kielpinski, David. Laser Cooling with Ultrafast Pulse Trains. Fort Belvoir, VA: Defense Technical Information Center, August 2011. http://dx.doi.org/10.21236/ada547504.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Gaffney, Kelly J. Ultrafast X-ray Science at the Sub-Picosecond Pulse Source. Office of Scientific and Technical Information (OSTI), September 2005. http://dx.doi.org/10.2172/878358.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Alessi, D. High-Average-Power Diffraction Pulse-Compression Gratings Enabling Next-Generation Ultrafast Laser Systems. Office of Scientific and Technical Information (OSTI), November 2016. http://dx.doi.org/10.2172/1333397.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Weiner, Andrew M. (BMDO-DURIP 98-22) Instrumentation for Research on Ultrafast Optical Pulse Processing and Applications. Fort Belvoir, VA: Defense Technical Information Center, April 1999. http://dx.doi.org/10.21236/ada368222.

Full text
APA, Harvard, Vancouver, ISO, and other styles
7

De Lucia, Jr, Gottfreid Frank, and Jennifer. Tailored Ultrafast Pulses for Selective Energetic Residue Sampling. Fort Belvoir, VA: Defense Technical Information Center, April 2008. http://dx.doi.org/10.21236/ada481996.

Full text
APA, Harvard, Vancouver, ISO, and other styles
8

Peter Pronko. Isotopically Enriched Films and Nanostructures by Ultrafast Pulsed Laser Deposition. Office of Scientific and Technical Information (OSTI), December 2004. http://dx.doi.org/10.2172/835030.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Bowlan, Pamela Renee. Ultrafast control and monitoring of material properties using terahertz pulses. Office of Scientific and Technical Information (OSTI), May 2016. http://dx.doi.org/10.2172/1334176.

Full text
APA, Harvard, Vancouver, ISO, and other styles
10

Fiedler, Curtis J. The Interferometric Detection of Ultrafast Pulses of Laser Generated Ultrasound. Fort Belvoir, VA: Defense Technical Information Center, April 1996. http://dx.doi.org/10.21236/ada312079.

Full text
APA, Harvard, Vancouver, ISO, and other styles
You might also be interested in the extended bibliographies on the topic 'Ultrafast Pulse' for particular source types:
Journal articles Dissertations / Theses Books
We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!

To the bibliography