Showing papers on "Femtosecond pulse shaping published in 1976"
TL;DR: In this paper, it was shown that continuous pulse shaping may be achieved by spreading the coherent pulse (30 psec) emitted by a mode-locked laser with the help of a convenient diffracting pupil.
48 citations
TL;DR: Passive pulse shapers including Fabry-Perot etalons, double-etalon, and classical beam splitters are examined both theoretically and experimentally for their temporal behavior.
Abstract: Passive pulse shapers including Fabry-Perot etalons, double-etalons, and classical beam splitters are examined both theoretically and experimentally for their temporal behavior. For temporally and spatially overlapped pulses, interpulse interference effects determine the resulting pulse shapes. The output pulses from such devices are expected to be of great importance for laser fusion pulse shaping.
40 citations
Patent•
25 May 1976
TL;DR: In this paper, the authors present a method for producing a sequence of radiation pulses with a pulse envelope of time variation which is controllable by an external electromagnetic signal applied to an active medium or by a sectored reflector, through which the radiation passes.
Abstract: Apparatus and method for producing a sequence of radiation pulses with a pulse envelope of time variation which is controllable by an external electromagnetic signal applied to an active medium or by a sectored reflector, through which the radiation passes
35 citations
TL;DR: The device described here can generate a wide variety of pulse shapes and widths by stacking a set of 30-psec mode-locked pulses, and currently shapes the pulses for the KMS Fusion neodymium-doped-glass laser system that has produced over 500 neutron-yielding shots since 1 May 1974.
Abstract: Current laser-fusion theory dictates the need for relatively short laser pulses that are shaped in time to implode optimally a fuel pellet. The laser pulse width and shape should be varied to match different types and sizes of targets. For current experiments, pulse widths as short as 100 psec are desirable, which eliminates the choice of relatively slow electrooptic shutters to shape the pulse, since they are limited to rise times and pulse widths longer than several hundred picoseconds. The device described here can generate a wide variety of pulse shapes and widths by stacking a set of 30-psec mode-locked pulses. This versatile pulse stacker currently shapes the pulses for the KMS Fusion neodymium-doped-glass laser system that has produced over 500 neutron-yielding shots since 1 May 1974 by heating and compressing deuterium or deuterium-tritium fuel inside hollow glass spherical targets.
34 citations
TL;DR: In this paper, a theoretical treatment of the onset and time evolution of ultrashort laser pulses is presented, and a theoretical model of the time evolution is presented for laser pulses.
22 citations
TL;DR: In this paper, the intensity correlation measurements of pulse widths for a sheet-flow rhodamine dye laser mode locked by synchronous gain modulation by a pulsed 2-W argon laser were reported.
Abstract: Intensity correlation measurements of pulse widths are reported for a sheet‐flow rhodamine dye laser mode locked by synchronous gain modulation by a pulsed 2‐W argon laser. For pump pulses 1–2‐ns long, the minimum dye pulse width obtained is 50 ps. The dye‐laser outputs in this pump pulse regime are discussed as a function of cavity length, pump power, and rhodamine and saturable absorber dye concentration.
16 citations
Patent•
25 May 1976
TL;DR: In this article, an active pulse stacking system including an etalon and an electro-optical modulator apparatus combined with a pulse-forming network capable of forming and summing a sequence of time-delayed optical waveforms arising from, for example, a single laser pulse.
Abstract: An active pulse stacking system including an etalon and an electro-optical modulator apparatus combined with a pulse-forming network capable of forming and summing a sequence of time-delayed optical waveforms arising from, for example, a single laser pulse. The Pockels cell pulse stacker may attain an efficiency of about 2.6% while providing a controllable faster-than-exponential time rise in transmitted pulse intensity.
16 citations
TL;DR: In this article, simple stability conditions for pulse propagation in a two-level system with linear scattering and combined homogeneous and inhomogeneous broadening are obtained for steady-state π and \pi\sqrt{2} area pulses.
Abstract: Simple stability conditions are obtained for pulse propagation in a two-level system with linear scattering and combined homogeneous and inhomogeneous broadening. Properties of steady-state π and \pi\sqrt{2} area pulses are reviewed. Computer simulation of an approach to equilibrium pulse propagation is presented in a few cases for initially perturbed pulses.
12 citations
TL;DR: In this paper, a 2.5 ns switched-out pulse from a mode-locked oscillator is truncated by generating its own gas breakdown in the focal spot between two lenses and then passed through a hot I2 absorber operated in the small-signal regime to generate a short FID pulse.
Abstract: We have generated 100–200‐ps iodine 1.315‐μ laser pulses by means of the free induction decay (FID) technique. A 2.5‐ns switched‐out pulse from a mode‐locked oscillator is truncated by generating its own gas breakdown in the focal spot between two lenses and then passed through a hot I2 absorber operated in the small‐signal regime to generate a short FID pulse. Streak camera studies of such pulses showed that the breakdown time was about 40 ps and the FID pulses had a full width at half‐maximum of about 100–200 ps. Subsequent amplification of a pulse showed that the 4‐GHz bandwidth of the atmospheric pressure iodine amplifier was insufficient to cover the pulse spectrum. A calculation of the pulse width based on the reduction of the small‐signal gain due to such spectral considerations also gave pulse widths in the 100–200‐ps range.
11 citations
Patent•
16 Jan 1976
TL;DR: An apparatus for controlling the pulse shape, i.e., the pulse duration and intensity pattern, of a pulsed laser system, is described in this paper, which is particularly well adapted for controlling a pellet ignition pulse in a laser-driven fusion reaction system.
Abstract: An apparatus for controlling the pulse shape, i.e., the pulse duration and intensity pattern, of a pulsed laser system, and which is particularly well adapted for controlling the pellet ignition pulse in a laser-driven fusion reaction system. The apparatus comprises a laser generator for providing an optical control pulse of the shape desired, a pulsed laser triggered by the control pulse, and a plurality of optical Kerr-effect gates serially disposed at the output of the pulsed laser and selectively triggered by the control pulse to pass only a portion of the pulsed laser output generally corresponding in shape to the control pulse.
7 citations
Patent•
16 Apr 1976
TL;DR: In this paper, a pulsed laser beam pulse is split so that part of the beam pulses are directed through an optical delay path, and the delayed pulse is then brought into the same path as the beam pulse transmitted through the sample and both be pulses are fed through a detector.
Abstract: A pulsed laser densitometer system measures highly optically dense samples. A pulsed laser beam pulse is split so that part of the beam pulse is directed through an optical delay path. The delayed beam pulse is then brought into the same path as the beam pulse transmitted through the sample and both beam pulses are fed through a detector. The output of the detector contains the optical density information in the ratio of the pulse amplitude of the transmitted pulse to the delayed pulse.
TL;DR: In this paper, the authors deal with measurements of picosecond laser pulse parameters such as temporal and spatial profile, and power, using the combined streak camera and optical multichannel analyzer system.
Abstract: This paper deals with measurements of picosecond laser pulse parameters such as temporal and spatial profile, and power. Pulseshape measurements were conducted by using the combined streak camera and optical multichannel analyzer system. The precision of measurements are discussed.
TL;DR: In this paper, a focusing interaction between a parabolic voltage pulse traveling in a transmission line filled with nonlinear dielectric and a laser pulse which crosses the guide at right angles is analyzed.
Abstract: We analyze a focusing interaction between a parabolic voltage pulse traveling in a transmission line filled with nonlinear dielectric and a laser pulse which crosses the guide at right angles. In this interaction the voltage pulse, which is about 1 nsec in duration, creates an effective cylindrical lens that moves across the optical wave front with a velocity greater than 109 cm/sec. The light is imaged by this disturbance to a focal spot which translates at the same velocity, producing the effect of a streak camera without the necessity of a photocathode and electron deflection. By placing a spatial filter, rather than a detector array, in the focal plane, subnanosecond shaping or gating of the input pulse can be achieved very simply.
Patent•
16 Dec 1976
Abstract: A system for shaping pulses of optical radiation includes a birefringent element for receiving a polarized pulse from a source of optical radiation and projecting the pulse into two orthogonally polarized beams. The birefringent element is designed to introduce a phase shift between the two beams during transmission therethrough, such that when the two beams are recombined at the output of the birefringent element, the shape of the pulse is modified with respect to the input pulse.
TL;DR: In this article, a cavity-dumped flashlamp-pumped dye laser that is capable of generating a varied temporal output either of trains or single pulses with energies from 0.1 to 0.5 mJ was presented.
Abstract: Many studies of molecular processes have utilized flashlamp-pumped dye lasers as a source of wavelength tunable, moderate energy (1 mJ) microsecond optical pulses. The chief attribute of such devices is the ability to generate a high concentration of excited states. Unfortunately, the temporal width of the output limits most investigations to relatively slow events. This drawback could be circumvented by shortening the pulses using any of several schemes. However, most of the commercially available approaches, such as pulse slicing or Q-switching, suffer from inflexible pulse shaping or the inability to conserve and deliver the original laser energy. On the other hand, it has been shown that cavity-dumping can be used with a CW dye laser to both store the radiation and then deliver it in a variety of optical waveforms ranging from sawtooth to Gaussian shapes. In this note we wish to report the construction of a cavity-dumped flashlamp-pumped dye laser that is capable of generating a varied temporal output either of trains or single pulses with energies from 0.1 to 0.5 mJ.
TL;DR: Pulse propagation in a photochemical iodine laser amplifier is investigated both experimentally and by solving the Maxwell-Schrodinger equations by computer in this article, where the numerical analysis includes reservoir effects due to tightly coupled hyperfine levels in the iodine groundstate and phase modulation (chirping) of the input pulse.
Abstract: Pulse propagation in a photochemical iodine laser amplifier is investigated both experimentally and by solving the Maxwell-Schrodinger equations by computer. Pulse shortening and pulse reshaping are observed in agreement with theory. For pulse durations approaching the dephasing time, it is found that a further decrease in duration by gain saturation is hard to obtain and requires high power levels or high initial inversion. The numerical analysis includes reservoir effects due to tightly coupled hyperfine levels in the iodine groundstate and phase modulation (chirping) of the input pulse. Comparison of the iodine parameters with those of Nd and CO2 lasers shows that for nanosecond pulses pulse shortening occurs more readily in the latter two systems in agreement with experiments.
TL;DR: An analysis of the propagation of a frequency-modulated light pulse in a linearly amplifying medium with an inhomogeneously broadened gain profile is made in this paper, where conditions are established under which strong distortions of the pulse shape may result in its splitting.
Abstract: An analysis is made of the propagation of a frequency-modulated light pulse in a linearly amplifying medium with an inhomogeneously broadened gain profile. It is shown that a pulse can be compressed considerably during amplification. Conditions are established under which strong distortions of the pulse shape may result in its splitting. An analysis is made of the influence of the phase self-modulation of radiation on the shape of ultrashort light pulses in oscillators and amplifiers.
01 Jan 1976
TL;DR: In this paper, the dispersive temporal compression of short-pulse light pulses has been discussed for many years, and a review can be found in Section 2.1].
Abstract: Analagous to chirp radar compression schemes, the dispersive temporal compression of “chirped” light pulses has been discussed for many years now. Here we briefly review developments of these optical pulse compression techniques. This scheme can provide pulses so short that they would otherwise be unavailable, and such a scheme has the potential for improving the efficiency of short-pulse laser amplifier chains.
01 Jan 1976
TL;DR: In this article, a survey is given on recent experiments and calculations concerning the excitation of short phonon pulses in the THz-frequency range by means of far infrared laser pulses.
Abstract: In this paper a survey is given on recent experiments1,2 and calculations3 concerning the excitation of short phonon pulses in the THz-frequency range by means of far infrared laser pulses. As we will see, this new technique allows to generate (spatial) coherent THz-phonons in X-quartz and to observe lattice dispersion directly by observing the frequency dependence of the group velocities of these phonon pulses. Since we will be concerned with coherent as well as with incoherent phonon radiators the difference is explained in Fig. 1 for an excitation at the X-face of a quartz crystal. If the phonon excitation takes place with equal phase over the radiator area we have a special kind of a coherent radiator which emits a highly collimated beam of phonons (in analogy to laser pulse emission in optics), whereas a statistically independent emission of phonons from adjacent radiator elements leads to an incoherent phonon emission, i.e. to an emission into all directions (in analogy to photon emission from a flash lamp). For incoherent phonon radiation a calculation of the phonon irradiance of the detector demands the detailed knowledge of the whole anisotropic phonon propagation in the crystal and the knowledge of the special q-space source distribution in the crystal near the radiator interface. One advantage of coherent phonon pulses consists in the fact that the whole phonon pulse energy remains concentrated in a small volume and can be transmitted over large distances (assuming no interactions), for example to the detector.
Patent•
04 May 1976
TL;DR: In this article, a high energy pulse having a very narrow pulse width is generated utilizing a wave guide pulse generator using a well-defined leading edge, which is then coupled to a first quadrature hybrid and a second pulse, shifted in phase relative to the modified first pulse, is generated in the first hybrid from, and in addition to, the modified second pulse.
Abstract: A high energy pulse having a very narrow pulse width is generated utilizing a wave guide pulse generator A first pulse having a pulse width greater than the desired pulse is modified to have a well-defined leading edge and is then coupled to a first quadrature hybrid A second pulse, shifted in phase relative to the modified first pulse, is generated in the first hybrid from, and in addition to, the modified first pulse The phase-shifted second pulse travels the length of a conventional wave guide so that the pulse is delayed before entering a second quadrature hybrid The second quadrature hybrid receives the modified first and phase-shifted second pulses andd phase shifts the second pulse so that the phase thereof is opposed to the phase of the modified first pulse The modified first pulse is then combined with the opposed phase-shifted second pulse Upon combining the opposed, phase-shifted, delayed second pulse with the modified first pulse, a major portion of the modified first pulse is cancelled and an output pulse is developed having a pulse width equal to the delay caused by the conventional wave guide
TL;DR: The present paper shows that a substantial improvement in accuracy can be obtained for a given pulse length by means of laser ranging systems using conventional length (long) pulses with a sharp leading edge pulse distribution.
Abstract: Many optical ranging systems currently use laser pulses of approximately Gaussian shape with widths of a few nanoseconds or less. The present paper shows that a substantial improvement in accuracy can be obtained for a given pulse length by means of laser ranging systems using conventional length (long) pulses with a sharp leading edge pulse distribution. The accuracy in such a case will improve roughly linearly with the signal strength. Order statistics is used to estimate the round-trip level travel time from the arrival time of the earliest photoelectron.