Showing papers on "Femtosecond pulse shaping published in 1972"
TL;DR: In this article, a theoretical treatment of the fluctuation mechanism involved in the generation of picosecond laser pulses with saturable absorbers is presented, where the processes responsible for shortening of the pulsewidth and for selection of the most intense pulse are treated.
Abstract: This paper presents a theoretical treatment of the fluctuation mechanism involved in the generation of picosecond laser pulses with saturable absorbers. The processes responsible for the shortening of the pulsewidth and for selection of the most intense pulse are treated. Some experimental results that confirmed the treatment are presented. The influence of inertia of saturable absorber and nonlinear losses (self-focusing and self-modulation) is discussed.
136 citations
TL;DR: In this article, single picosecond light pulses from a mode-locked Nd:glass laser are investigated by several methods, including three-photon fluorescence, photoelectric measurements, and quantitative studies of the contrast ratio of the two-phase fluorescence.
Abstract: Single picosecond light pulses from a mode-locked Nd:glass laser are investigated by several methods. Their temporal structure is studied by two-photon fluorescence. The frequency spectra are measured quantitatively. The energy distribution is simultaneously investigated by three-photon fluorescence, photoelectric measurements, and quantitative studies of the contrast ratio of the two-photon fluorescence. The pulse shape is measured using a method based on the stimulated Raman effect. It is observed that the pulses are weakly asymmetric-the pulse decay is slower (exponential) than the pulse rise (Gaussian). Bandwidth-limited pulses of 4-8 ps are present in the leading part of the pulse train. Substantial frequency broadening develops as the pulse train reaches its maximum and a subpicosecond structure is formed in the trailing part of the pulse train.
96 citations
TL;DR: In this article, simple expressions are given that relate the duration of a self-phase modulated ultrashort optical laser pulse to the number of minima (or maxima) and the maximum Stokes (or anti-Stokes) frequency shift of its spectrum.
Abstract: Simple expressions are given that relate the duration of a self-phase modulated ultrashort optical laser pulse to the number of minima (or maxima) and the maximum Stokes (or anti-Stokes) frequency shift of its spectrum.
29 citations
Patent•
07 Aug 1972TL;DR: In this paper, a method and an apparatus are disclosed for generating laser pulses having a time duration on the order of subnanoseconds. They are generated by causing a laser to lase and removing the bulk of the radiation contained in the laser cavity.
Abstract: Both a method and an apparatus are disclosed for generating laser pulses having a time duration on the order of subnanoseconds. These light pulses also have a high output power. They are generated by causing a laser to lase and removing the bulk of the radiation contained in the laser cavity. The remaining radiation or light extends over only a short length of the cavity. This light pulse is mode locked, that is it consists of individual Fourier components of the proper phase so that the short light pulse retains its shape while being amplified again in the laser cavity. This short-duration light pulse may then be made to issue from the cavity. Alternatively, the amplified light may be made to issue as a pulse train or set of pulses. Finally, a single pulse may be utilized for mode locking another laser where the ultra-short time-duration pulse may be amplified again. This may be considered priming and subsequent mode locking of the second laser.
22 citations
TL;DR: In this article, single pulses of 1-ns duration were generated at 106-μ wavelength using a pulse selection scheme in conjunction with an actively mode-locked CO 2 TEA oscillator.
Abstract: Single pulses of 1-ns duration have been generated at 106-μ wavelength using a pulse-selection scheme in conjunction with an actively mode-locked CO 2 TEA oscillator The experimental setup and its operating characteristics are presented A technique is described, which yields pulse extinction ratios of approximately 900:1
17 citations
TL;DR: In this paper, a theory of the resonant interaction between an ultrashort coherent light pulse and a semiconductor was given, which occurs when the pulse duration is less than the polarization or phase memory relaxation time.
Abstract: A theory is given of the resonant interaction between an ultrashort coherent light pulse and a semiconductor, which occurs when the pulse duration is less than the polarization or phase memory relaxation time. It is shown that, under certain conditions, a stationary 2? pulse can form. Numerical estimates of the velocity of propagation of a stable pulse are obtained for a typical semiconductor.
13 citations
Patent•
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TL;DR: In this article, double pulses are produced from a single laser by generating two successive optical pumping pulses from the same flash lamp and Qswitching once after each pumping pulse prior to the next pumping pulse.
Abstract: Double pulses are produced from a single laser by generating two successive optical pumping pulses from the same flash lamp and Qswitching once after each pumping pulse prior to the next pumping pulse.
11 citations
TL;DR: In this paper, a Nd3+:YAG laser with multiple mode locking was used to obtain optical pulses up to 1.25 Gbit/s with the carrier frequency of mode-locked pulses tuned through several tens of gigahertz by tilting an intracavity tuning etalon.
Abstract: Optical pulses up to 1.25 Gbit/s were obtained with a Nd3+:YAG laser by multiple mode locking. The carrier frequency of mode-locked pulses was tuned through several tens of gigahertz by tilting an intracavity tuning etalon. Some detuning effects in forced mode locking will be also presented.
10 citations
TL;DR: In this paper, it was shown that short intense light pulses of optical filaments can form an optical shock at the leading edge in the usual Kerr liquids, under certain conditions an extremely sharp spike occurs at the front of the pulse.
Abstract: It is shown theoretically that short intense light pulses of optical filaments can form an optical shock at the leading edge in the usual Kerr liquids. Under certain conditions an extremely sharp spike occurs at the front of the pulse.
10 citations
Patent•
19 Apr 1972TL;DR: In this article, an active laser medium, a modulator, a mode selector and an optical resonator are used to create a stable pulse with short pulse spacings, where the mode selector is an optical filter for a mode group.
Abstract: A laser arrangement for creating a stable pulse with short pulse spacings, comprising an active laser medium, a modulator, a mode selector and an optical resonator, wherein the mode selector is an optical filter for a mode group.
TL;DR: In this article, the inner conductor of a rigid coaxial transmission line having air dielectric, commonly referred to as an air line, was designed and built for producing a pulse whose leading edge is a linear ramp, a truncated Gaussian function, and the integral of a truncation of a GAs.
Abstract: For the purpose of checking very fast time-domain reflectometer (TDR) systems it is desirable to have a fast rise-time pulse whose parameters are known. A means for obtaining pulses meeting these requirements has been achieved by suitably tapering the inner conductor of a rigid coaxial transmission line having air dielectric, commonly referred to as an air line. The air line is driven with a pulse that has a very fast rise time compared to the rise time of the expected output pulse. A reflected pulse will be generated whose shape is dependent upon the taper of the inner conductor. A procedure is outlined for determining the proper taper to shape the leading edge of the reflected pulse to match any continuous single-valued function. Air lines that were designed and built for producing a pulse whose leading edge is a linear ramp, a truncated Gaussian function, and the integral of a truncated Gaussian function are discussed and traces of these pulses are shown. The problem of re-reflections due to the multiple discontinuities along the air line was analyzed by means of a computer. This program is described. The effect of the driving-pulse parameters on the reflected pulse is analyzed on a theoretical basis. Rise time, pulse shape, and aberrations such as overshoot and ringing of the driving pulse are considered in this analysis.
TL;DR: In this article, the output of active Fabry-Perot cavity was described in a unified way, using Fourier analysis, and a novel model for treating an active FPN cavity, including the case of high gain, was developed resulting in a more exact expression for the spectral width of the cavity modes.
Abstract: The output of lasers in various modes of operation is described in a unified way, using Fourier analysis. A novel model for treating an active Fabry-Perot cavity, including the case of high gain, is developed resulting in a more exact expression for the spectral width of the cavity modes. Simple mathematical tools are given to relate the observed pulse length with the average gain and with the initial population inversion in the laser medium. It is shown that lasers with homogeneously broadened spectral lines have cavity modes of equal width and that if the modes are locked together the resulting ultrashort pulses are of equal duration. For lasers with inhomogeneously broadened spectral lines the cavity modes vary in width along the gain curve and, when mode-locked, the ultrashort pulses increase monotonically in duration along the emitted pulse train.
Patent•
29 Jun 1972
TL;DR: In this paper, the leading edges of the pulses are sliced by slicing the fixed position leading edges, which reduces the noise accompanying the demodulated signals and does not affect the pulse width modulation represented by the position of the lagging edges.
Abstract: System for separating pulses containing information in a pulse width modulated pulse train, wherein the leading edges of the pulses occur at a fixed repetition rate. Noise which occurs on the leading edge of the pulses is reduced by slicing the fixed position leading edges. A gating wave stabilized by the received pulse train, and which is insensitive to wide band noise, opens a gate for the pulses after the leading edge of each pulse, and closes the gate before the leading edge of the next pulse. A plurality of gates can be provided to separate pulse trains which are multiplexed to form a composite pulse train. The gates do not affect the pulse width modulation represented by the position of the lagging edges of the pulses and reduces the noise accompanying the demodulated signals.
01 Jan 1972
TL;DR: In this paper, a high efficiency microwave avalanche diode has been used to generate high power GHz-rate pulses, and the amplitude is 125 V into a 50-ohm load and the width is 400 ps, risetime 100 ps, and falltime 200 ps.
Abstract: A high-efficiency microwave avalanche diode has been used to generate high-power GHz-rate pulses. Pulse amplitude is 125 V into a 50-ohm load. Pulsewidth is 400 ps, risetime 100 ps, and falltime 200 ps.