Showing papers on "Femtosecond pulse shaping published in 1991"
Book•
01 Oct 1991
TL;DR: In this paper, short optical pulses are used in Linear Dispersive Media (LDM) for self-modulation, self-compression and self-shaping of optical pulses.
Abstract: Contents: Short Optical Pulses in Linear Dispersive Media. Self-action of Optical Pulses Self-modulation, Self-compression, Solitons, and Instabilities. Parametric Interactions and Coherent Scattering of Femtosecond Pulses. Fast Phase Control. Compression and Shaping of Optical Pulses. Optical Solitons. Picosecond and Femtosecond Pulses in Optical Information Systems.
665 citations
TL;DR: A high-speed streak camera detector was used to determine the duration of these x-ray pulses, and computer simulations of the plasmas agree with the experimental results, predicting that brighter and more efficient x-rays are obtained by the use of more intense laser pulses.
Abstract: A high-temperature plasma is created when an intense laser pulse is focused onto the surface of a solid. An ultrafast pulse of x-ray radiation is emitted from such a plasma when the laser pulse length is less than a picosecond. A high-speed streak camera detector was used to determine the duration of these x-ray pulses, and computer simulations of the plasmas agree with the experimental results. Scaling laws predict that brighter and more efficient x-ray sources will be obtained by the use of more intense laser pulses. These sources can be used for time-resolved x-ray scattering studies and for the development of x-ray lasers.
339 citations
TL;DR: A direct measurement of the amplitude and the phase of a femtosecond light pulse is performed for the first time to the authors' knowledge, and the time dependence of the field can be easily obtained by a Fourier transform.
Abstract: A direct measurement of the amplitude and the phase of a femtosecond light pulse is performed for the first time to our knowledge The measurement is made in the frequency domain, and the time dependence of the field can be easily obtained by a Fourier transform The technique relies on a pulse synthesis scheme to unravel the frequency dependence of the phase A mask filters the spectrum, which gives rise to a pulse with a measurable temporal profile related to the frequency dependence of the phase In particular, with a rectangular slit the time delay of the synthesized pulse is the first derivative of the phase with respect to the frequency of the original pulse at the central frequency of the filter The amplitude of the spectrum is obtained from the power spectrum
233 citations
TL;DR: In this article, the authors used terahertz-rate trains of femtosecond pulses for repetitive impulsive excitation of individual phonon modes in an α-perylene molecular crystal.
Abstract: Optical control of elementary molecular motion through impulsive stimulated Raman scattering is enhanced by means of timed sequences of femtosecond pulses that are produced by pulse-shaping techniques. In particular, terahertz-rate trains of femtosecond pulses are used for repetitive impulsive excitation of individual phonon modes in an α-perylene molecular crystal. When the pulse repetition rate is matched to the desired phonon frequency, mode-selective vibrational amplification is achieved. A comparison of data acquired with the transient-grating and the pump–probe experimental geometries reveals the timing dynamics of the induced phonon oscillations with respect to the driving femtosecond pulse sequence.
165 citations
TL;DR: The generation of bandwidth-limited shoulder-free 125-fsec pulses by additive-pulse-compression mode locking of a neodymium glass laser is described, allowing stable pulse generation under the condition of large pulse shaping in the cavity.
Abstract: The generation of bandwidth-limited shoulder-free 125-fsec pulses by additive-pulse-compression mode locking of a neodymium glass laser is described. An all-fiber nonlinear amplifying loop mirror is employed as a fast saturable absorber and permits stable pulse generation under the condition of large pulse shaping in the cavity.
111 citations
TL;DR: A 30-TW,1.0-ps laser pulse has been generated by chirped-pulse amplification in a large-aperture Nd:phosphate glass laser system and a peak-to-prepulse intensity ratio of better than 10 was obtained by temporal windowing of a self-phase-modulated chirping pulse before amplification and compression.
Abstract: A 30-TW,1.0-ps laser pulse at 1053 nm has been generated by chirped-pulse amplification in a large-aperture Nd:phosphate glass laser system. A peak-to-prepulse intensity ratio of better than 10(7) was obtained by temporal windowing of a self-phase-modulated chirped pulse before amplification and compression.
81 citations
Proceedings Article•
12 May 1991
33 citations
Patent•
10 Jun 1991
TL;DR: In this paper, a variation signal corresponding to differences between the sensed light intensity and the reference pulse is fed to a Pockels cell or Q-switch within the resonator.
Abstract: A method or apparatus for controlling the output pulse of a Q-switched laser. The intensity of laser light within the resonator of a Q-switch laser is sensed. A reference pulse related to a desired laser output pulse shape is compared with the sensed intensity. A variation signal corresponding to differences between the sensed light intensity and the reference pulse is fed to a Pockels cell or Q-switch within the resonator. The Q-switch responds to the variation signal by altering the resonator laser light polarization to maintain the Q-switch laser's output pulse in the desired shape. The reference pulse may be dynamically altered to change the shape of the output pulse.
30 citations
TL;DR: In this article, a study of the possibility of using fiber-grating compression devices for reducing the width of ultrashort laser pulses was made, and the results were given of numerical investigations of the process of self-interaction of frequency-modulated pulses in single-mode fiber waveguides used to optimize the spectral compressor.
Abstract: A study is made of the possibility of using fiber-grating compression devices for reducing the width of ultrashort laser pulses. The results are given of numerical investigations of the process of self-interaction of frequency-modulated pulses in single-mode fiber waveguides used to optimize the spectral compressor.
30 citations
18 Mar 1991
TL;DR: In this article, the authors reported 800mW at sub-100fs (when pumped with 8W) and 2.1W with 120fs pulsewidth (pumped with 14W).
Abstract: Ti:Al2O3 has the available bandwidth for directly generating very short tunable pulses at high average power. Passive modelocking techniques have been described in the literature [1], [2]. We report 800mW at sub-100fs (when pumped with 8W) and 2.1W output with 120fs pulsewidth (pumped with 14W).
29 citations
01 Jun 1991
TL;DR: In this paper, the optical pulse response analysis of a fiber ring resonator is presented, and it is shown that several interesting functions, such as optical pulse differentiation, integration or delay, trigger pulse generation, and equalisation of fiber dispersion can be realized by using the resonator.
Abstract: This article presents the optical pulse response analysis of a fibre ring resonator. It is shown that several interesting functions, namely optical pulse differentiation, integration or delay, trigger pulse generation, and equalisation of fibre dispersion can be realised by using the resonator. The theory is presented in an easy to understand manner, by first considering the steady-state response. The results of the transient pulse response are explained in relation to the steady state results. The results related to optical pulse shaping will be of interest to the future when coherent optical pulse and switching circuits will become available. loop delay =
TL;DR: In this paper, a technique for shaping an ultrashort pulse and measuring a pulse shape in real time using an optically induced dynamic grating in a nonlinear material is presented.
Abstract: We report a new technique for shaping an ultrashort pulse and measuring a pulse shape in real time using an optically induced dynamic grating in a nonlinear material. The technique is all optically controllable, not limited by electronic switching time, and works over a wide range of wavelengths. We demonstrate the technique by using three kinds of nonlinear materials: a Bi12SiO20 (BSO) crystal, a DODCI solution and a ZnSe film.
TL;DR: In this paper, the authors investigated the femtosecond soliton pulses with various wavelengths and found that the soliton self-frequency shift occurs along with the pulse width narrowing.
Abstract: Amplification characteristics of erbium‐doped optical fiber amplifier have been investigated using femtosecond soliton pulses with various wavelengths. Soliton trapping is not observed for 210 fs input pulses at 1.535 μm but the soliton self‐frequency shift occurs along with the pulse‐width narrowing. When the input pulse width is 470 fs, the soliton pulse is amplified by the optical gain at 1.535 μm, where the gain bandwidth is broader than the bandwidth of the input pulse. Amplification characteristics at other nonresonant wavelengths are also investigated using a femtosecond soliton pulse.
TL;DR: In this paper, a significant shortening of the output pulse duration in an actively mode-locked laser was observed when one of the laser mirror was replaced with a nonlinear mirror, based on second harmonic generation.
Patent•
12 Jul 1991
TL;DR: In this paper, a single ultrashort laser radiation pulse is split into two partial pulses which are each conducted through one of two TREACY compressors having different group delay dispersions and then recorded in succession on the same time basis with a streak camera.
Abstract: For the acquisition of data for determining the duration and chirp (frequency modulation) of a single ultrashort laser radiation pulse said pulse is split into two partial pulses which are each conducted through one of two TREACY compressors having different group delay dispersions and then recorded in succession on the same time basis with a streak camera.
TL;DR: In this article, a configuration of a reflected-wave amplifier with single-side external coupling is introduced for pulse shaping, which is found to be suitable for enhancing dynamic gain saturation, and a combination of a distributed feedback laser oscillator at 1.3 mu m in wavelength and a reflectedwave amplifier of 400 mu m cavity length with asymmetric facet reflectivities of 0.01% and 30%, single-mode optical pulses with almost no tailing, full width at half maximum of 15 ps, and peak power exceeding 50 mW were obtained without pulse broadening, despite the considerable
Abstract: To obtain high power, well shaped picosecond pulses from gain-switched semiconductor lasers, the use of dynamic gain saturation characteristics of semiconductor laser amplifiers was investigated theoretically and experimentally. A configuration of a reflected-wave amplifier (RWA) with single-side external coupling is introduced for pulse shaping, which is found to be suitable for enhancing dynamic gain saturation. By a combination of a distributed feedback laser oscillator at 1.3 mu m in wavelength and a reflected-wave amplifier of 400 mu m cavity length with asymmetric facet reflectivities of 0.01% and 30%, single-mode optical pulses with almost no tailing, full width at half maximum of 15 ps, and peak power exceeding 50 mW were obtained without pulse broadening, despite the considerable tail structure of the incident pulse. >
TL;DR: In this article, a high-power femtosecond dye-laser system based on a CPM oscillator was presented, with an energy up to 0.6 mJ and a variable pulse duration between 70 fs and 5 ps.
TL;DR: In this article, the tunability of both the wavelength and the pulsewidth of monolithic mode-locked semiconductor lasers is demonstrated, and a temperature-tuned CPM quantum-well laser is used to achieve near transform-limited time-bandwidth products of 0.34.
Abstract: The tunabilities of both the wavelength and the pulse-width of monolithic mode-locked semiconductor lasers are demonstrated. Pulses shorter than 1.6 ps, tunable over 8.8 mu m, have been generated by a temperature-tuned monolithic colliding pulse mode-locked (CPM) quantum-well laser. For a fixed wavelength, the pulse-width is independently controlled from 1.2 ps to longer than 3 ps by external bandpass filters. Near transform-limited time-bandwidth products of 0.34 were maintained throughout the tuning processes. >
TL;DR: In this paper, the interplay of coherent and Raman effects on femtosecond soliton collapse and pulse train generation in erbium-doped fiber amplifiers is examined.
Abstract: The study of the interplay of coherent and Raman effects on femtosecond soliton collapse and pulse train generation in erbium‐doped fiber amplifiers is examined.
TL;DR: In this paper, the authors describe the generation and propagation of ultrashort optical pulses, and some methods for generating femtosecond optical pulses are described in the chapter, which are used in the field of optical communications and data processing.
Abstract: Publisher Summary This chapter describes the generation and propagation of ultrashort optical pulses. The generation of ultrashort pulses can be recognized as a problem for “making in phase” a great number of frequencies, whereas the interaction processes lead to dephasing of these frequencies. In most cases of light-matter interaction, the effects caused by the quantum-noise fluctuations are negligible or they can be described phenomenologically. The chapter discusses the theoretical basis necessary to study the light-matter interaction. The simultaneous action of both the lasing medium and resonator leads to the formation of subpicosecond optical pulses. Some methods for generating femtosecond optical pulses are described in the chapter. The linear and nonlinear effects appear when a femtosecond pulse propagates in free space or in substances. Some applications in the field of optical communications and data processing are presented in the chapter.
TL;DR: This technique should prove useful for a variety of ultrashort pulse applications including high repetition rate optical pulse amplification studies, electronic and optical material characterization, optical chaos experiments, and impulsively driven spectroscopy.
Abstract: We present a simple method for multiplying the pulse repetition frequency of a given cw mode-locked laser. We report, in particular, the doubling and tripling of the c/2L frequency of a synchronously pumped mode-locked dye laser. This technique should prove useful for a variety of ultrashort pulse applications including high repetition rate optical pulse amplification studies, electronic and optical material characterization, optical chaos experiments, and impulsively driven spectroscopy.
01 Jun 1991
TL;DR: In this paper, the authors have directly observed the nonlinear reflectivity of the plasma mirror as well as the spatial and temporal characteristics of the reflected pulse, and the initial measurements indicate that the incident pulse reflects specularly from a high density, highly reflective plasma.
Abstract: The plasma mirror is a self-induced, plasma-based optical element which can be inserted into existing experiments to reduce prepulse energy without significant degradation of ultrashort pulse laser light. We have directly observed the nonlinear reflectivity of the plasma mirror as well as the spatial and temporal characteristics of the reflected pulse. The initial measurements indicate that the incident pulse reflects specularly from a high density, highly reflective plasma. The reflected pulse has a smoothed spatial profile and reduced pulsewidth. We outline future work to characterize both the plasma mirror technique of prepulse suppression and its reflected pulse.
TL;DR: In this article, fast Fourier transforms are applied for the determination of the frequency spectra caused by self-phase modulation and the temporal shapes caused by grating pair pulse compression.
Abstract: The intracavity self-phase modulation in a picosecond Nd : glass laser and the external pulse compression in a grating pair arrangement is simulated. Fast-Fourier transforms are applied for the determination of the frequency spectra caused by self-phase modulation and the temporal shapes caused by grating pair pulse compression. The calculations are compared with recently reported experimental results.
Patent•
26 Feb 1991
TL;DR: In this paper, a method of driving a multimode laser diode has pulse circuitry providing a sequence of drive current pulses to the laser and modulation circuitry superimposing a modulation current upon the drive current pulse.
Abstract: A method of driving a multimode laser diode has pulse circuitry providing a sequence of drive current pulses to the laser and modulation circuitry superimposing a modulation current upon the drive current pulses. When the modulation amplitude and rate are sufficiently great, rapid switching of transverse modes of laser operation is induced during each laser pulse. The effect of many different modes is averaged out so that the observed light output, even in a high power apertured system, is stable both within a single pulse and from one pulse to the next.
TL;DR: In this article, the pulse development in colliding pulse mode-locked dye lasers is analyzed theoretically and the steady-state pulse duration is determined by equal pulse broadening and pulse shortening within a single resonator round-trip.
Abstract: The pulse development in colliding pulse mode-locked dye lasers is analysed theoretically. The chosen parameters belong to a c.w. argon laser pumped linear resonator arrangement with rhodamine 6G in ethylene glycol as gain medium and DODCI (3,3′-diethyloxadicarbocyanine iodide) in ethylene glycol as saturable absorber. The pulse shortening and pulse broadening effects in the laser oscillator are investigated. The steady-state pulse duration is determined by equal pulse broadening and pulse shortening within a single resonator round-trip. The detuning of the absorber jet out of the middle position of the resonator is considered. Multiple transits through the resonator are simulated to study the influence of various resonator and dye parameters on the pulse development and the background signal suppression. Fast relaxations within theS
1 andS
0-state of DODCI are necessary for sufficient background suppression to obtain femtosecond pulse trains.
TL;DR: In this paper, a simple and reliable technique to temporally shorten a multinanosecond Nd:glass laser pulse to less than nanosecond duration at the second harmonic wavelength is described.
Abstract: A simple and reliable technique to temporally shorten a multinanosecond Nd:glass laser pulse to less than nanosecond duration at the second harmonic wavelength is described in this article. Using this technique a short probe pulse synchronized with the main laser was generated for optical probing of laser‐produced plasmas. Experiments reported were conducted with a Nd:glass laser of wavelength 1.06 μm and of 20 ns duration to yield a temporally shortened pulse of duration less than a nanosecond at a wavelength of 0.53 μm. This technique would be particularly useful and give better results for shorter wavelength lasers (UV and VUV) for which the conventional techniques of pulse slicing are sophisticated as well as add to the expense and complexity of the laser system.
TL;DR: In this paper, the effect of using a single longitudinal-mode laser source with a Gaussian power spectrum to modulate a periodic pulse train is considered, and the resulting expressions for regenerative periodic pulse trains are analyzed as functions of the source linewidth.
Abstract: A periodic pulse train launched within a linear dispersive optical fiber regenerates itself at distances that depend on the period of the pulse train. The effect of using a single longitudinal-mode laser source with a Gaussian power spectrum to modulate a periodic pulse train is considered, and the resulting expressions for regenerative periodic pulse trains are analyzed as functions of the source linewidth. It is shown that these pulse trains decay exponentially. Effects of operating such systems in the first- and second-order dispersion regimes are considered. >
TL;DR: In this paper, a single optical pulse from a Q-switched Nd:YAG laser was split using polarizing optics so that one pulse was guided directly to the experimental holographic recording setup; the other pulse was sent first into the White cell, emerging a set number of nanoseconds later.
Abstract: To investigate shock wave propagation in air, optical pulses with temporal separations ranging from 53 to 425 ns have been generated for use in double‐exposure pulsed holography using a White cell [J. U. White, J. Opt. Soc. Am. 32, 285 (1942)] as an optical delay element. A single optical pulse from a Q‐switched Nd:YAG laser was split using polarizing optics so that one pulse was guided directly to the experimental holographic recording setup; the other pulse was sent first into the White cell, emerging a set number of nanoseconds later. This delayed pulse then was used to record a second holographic exposure. Using the White cell construction, reproducible pulse separations between 53 and 425 ns could be generated. Shock wavefronts propagating at velocities greater than Mach 20 have been recorded using this method.
TL;DR: A NaCl color-center amplifier is used to amplify femtosecond pulses from an additive-pulse mode-locked laser to generate a continuum in a variety of solid and liquid media for hours without optical damage.
Abstract: A NaCl color-center amplifier is used to amplify femtosecond pulses from an additive-pulse mode-locked laser at wavelengths between 1.52 and 1.60 μm. Pulse energies of several microjoules are obtained with pulse widths as short as 100 fs at kilohertz repetition rates. These pulses have been used to generate a continuum in a variety of solid and liquid media for hours without optical damage. The continuum generated in BaF2 covers the wavelength range of 400 nm < λ < 3.5 μm.
01 Jul 1991
TL;DR: In this article, a rotating mirror Q-switched Cr:Tm:Ho:YAG-laser ((λ = 2.12 micrometers) is described.
Abstract: The mid-infrared pulsed Holmium lasers operating around (lambda) approximately equals 2 micrometers are gaining more and more significance for numerous medical applications especially due to the ability to transmit the IR laser energy via recently available fiber-optic delivery systems. This paper describes a rotating mirror Q-switched Cr:Tm:Ho:YAG-laser ((lambda) equals 2.12 micrometers ) generating pulse durations in the microsecond(s) region. Pulse lengths up to 10 microsecond(s) have been achieved. This time domain is expected to offer several advantages for medical applications compared to the free running pulse length of around 300 microsecond(s) as well as to the 200 ns unstretched Q-switched pulse duration. Shock waves produced by laser induced plasmas have been investigated and analysed with these pulses and the fiber fragmentation resulting from the optical breakdown at high power densities was evaluated.© (1991) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.