Showing papers on "Femtosecond pulse shaping published in 1993"
TL;DR: The frequency-resolved optical gating (FROG) technique as discussed by the authors was proposed to measure the spectrum of the signal pulse as a function of the delay between two input pulses and the resulting trace of intensity versus frequency and delay is related to the pulse's spectrogram a visually intuitive transform containing time and frequency information.
Abstract: The frequency-resolved optical gating (FROG) technique for characterizing and displaying arbitrary femtosecond pulses is presented. The method is simple, general, broadband, and does not require a reference pulse. Using virtually any instantaneous nonlinear-optical effect, FROG involves measuring the spectrum of the signal pulse as a function of the delay between two input pulses. The resulting trace of intensity versus frequency and delay is related to the pulse's spectrogram a visually intuitive transform containing time and frequency information. It is proven using phase retrieval concepts that the FROG trace yields the full intensity I(t) and phase phi (t) of an arbitrary ultrashort pulse with no physically significant ambiguities. FROG appears to have temporal resolution limited only by the response of the nonlinear medium. The method is demonstrated by using self-diffraction through the electronic Kerr effect in BK-7 glass and 620-nm, linearly chirped, approximately 200-fs pulses of a few microjoules. >
846 citations
TL;DR: In this paper, the authors developed a simple, high-speed, nearly vibration-free, mechanically scanned, optical delay line suitable for femtosecond time-resolved signal-averaging measurements.
Abstract: We have developed a simple, high-speed, nearly vibration-free, mechanically scanned, optical delay line suitable for femtosecond time-resolved signal-averaging measurements. We demonstrate a 2-ps time window autocorrelator with a display updated at 400 Hz. The delay line uses a dithering planar mirror as a time-varying linear phase ramp in the spectral plane of a modified grating-lens femtosecond pulse shaper. The time delay is linearly proportional to the angular deviation of the mirror. The high speed and low vibration are a result of the extremely small angular changes required to generate a large time delay.
205 citations
TL;DR: This work reports programmable femtosecond pulseshaping using two commercially avaliable liquid crystal spatial light modulators (SLM) that allows generation of waveforms with arbitrary temporal phase and amplitude profiles within a 2.9 picosecond time window with features of less than 100 femToseconds.
Abstract: We report programmable femtosecond pulseshaping using two commercially avaliable liquid crystal spatial light modulators (SLM). This allows generation of waveforms with arbitrary temporal phase and amplitude profiles within a 2.9 picosecond time window with features of less than 100 femtoseconds. Such waveforms suggest exciting prospects for the control of chemical behaviour.
167 citations
TL;DR: In this article, the authors reported the simultaneous generation of two collinear synchronous mode-locked pulse trains, with central wavelength separations of 60 to 80 nm, from a single-cavity modelocked Ti:sapphire laser.
Abstract: We report the simultaneous generation of two collinear synchronous mode-locked pulse trains, with central wavelength separations of 60 to 80 nm, from a single-cavity mode-locked Ti:sapphire laser. Near-transform-limited pulses of duration 50 to 70 fs were generated at each wavelength, with jitter of less than 20 fs between the two-color pulses. These pulses were directly used to generate infrared pulses centered at 9 μm, by difference-frequency mixing in an AgGaS2 crystal.
113 citations
TL;DR: A new method is described—chronocyclic tomography—for determining the amplitude and phase structure of a short optical pulse, based on measurements of the energy spectrum of the pulse after it has passed through a time–frequency-domain imaging system.
Abstract: We describe a new method—chronocyclic tomography—for determining the amplitude and phase structure of a short optical pulse. The technique is based on measurements of the energy spectrum of the pulse after it has passed through a time–frequency-domain imaging system. Tomographic inversion of these measured spectra yields the time–frequency Wigner distribution of the pulse, which uniquely determines the amplitude and phase structure.
108 citations
TL;DR: In this article, the authors describe the generation of femtosecond waveforms by using frequency-domain phase-only filters designed by numerical optimization techniques and demonstrate the ability to generate high-quality terahertz-repetition-rate sequences of femto-cond pulses by means of low-loss phase only filtering.
Abstract: We describe generation of shaped femtosecond waveforms by using frequency-domain phase-only filters designed by numerical optimization techniques. The task of filter design for pulse shaping in the time domain is directly analogous to the design of phase-only filters for beam shaping and array generation in the spatial domain. We experimentally tested phase filters that were designed to produce ultrafast square and triangle pulses and femtosecond pulse sequences. Our results demonstrate the ability to generate high-quality terahertz-repetition-rate sequences of femtosecond pulses by means of low-loss phase-only filtering. On the other hand, experiments that tested generation of individual shaped pulses, such as square pulses, were less successful than previous experiments that used simultaneous phase and amplitude filtering. Our results indicate the importance of building increased robustness against variations in the input pulse shape into the phase-only filter design.
103 citations
TL;DR: In this article, a simple technique for generating a transform-limited optical short pulse with variable repetition rates by using a sinusoidally driven InGaAsP electroabsorption modulator without any optical resonators is presented.
Abstract: The authors propose and demonstrate a simple technique for generating a transform-limited optical short pulse with variable repetition rates by using a sinusoidally driven InGaAsP electroabsorption modulator without any optical resonators. Using the pulse compression effect due to nonlinear attenuation characteristics of the modulator, a transform-limited optical pulse can be generated just with sinusoidal modulation. Theoretical calculations and experimental results show that the pulse shape is very close to the sech/sup 2/ shape, and the pulse width can be easily varied by varying the bias and modulation voltages. Transform-limited optical pulse generation with a minimum pulse width of 11 ps was achieved up to 20-GHz repetition rate. The time-bandwidth product was as small as 0.32. >
101 citations
Journal Article•
TL;DR: In this paper, the self-channeling problem of a high-power ultrashort laser pulse in matter is solved, and the relativistic and ponderomotive nonlinearities are treated for free electrons, with the ions assumed to be at rest.
Abstract: The time-dependent spatially two-dimensional problem of the self-channeling of a high-power ultrashort laser pulse in matter is solved. The relativistic and ponderomotive nonlinearities are treated for free electrons, with the ions assumed to be at rest. The novelty of the model consists in including the longitudinal component of the ponderomotive force for the electrons along with the wave interaction between neighboring transverse segments of the pulse. The two-dimensional calculations are visualized as a sequence of \"snapshots\" of the pulse as a whole at different times. In the process of nonlinear propagation, strong dynamic modulation of the spatial shape of the pulse in the direction of propagation is observed, which causes the spectrum to broaden.
100 citations
TL;DR: In this article, a third-order correlation system has been developed, which enables the contrast ratio of high-intensity ultra-short laser pulses to be measured on a single shot with a dynamic range of better than 108.
Abstract: A third-order correlation system has been developed, which enables the contrast ratio of high-intensity ultra-short laser pulses to be measured on a single shot, with a dynamic range of better than 108.
82 citations
TL;DR: In this article, a two-color stimulated Raman effect was used to generate a shorter optical pulse at terawatt levels based on a simple optical system, which is essential in studies on ultrafast phenomena and nonlinear spectroscopy.
81 citations
TL;DR: 250-fs pulses have been generated directly from a passively mode-locked ytterbium–erbium figure-of-eight laser, made to produce regular pulse bursts at the round-trip frequency, with repetition rates in excess of 300 GHz.
Abstract: 250-fs pulses have been generated directly from a passively mode-locked ytterbium–erbium figure-of-eight laser. In addition to the usual characteristic of one pulse per round trip, the laser could be made to produce regular pulse bursts at the round-trip frequency, with repetition rates in excess of 300 GHz.
TL;DR: In this paper, a novel oscillator was developed as a driver producing ≈ ps pulses at 105 nm, which was stretched prior to amplification and compressed at an aperture of 150 mm.
TL;DR: In this article, the propagation and compression of a broadband pulse in a chirped-pulse-amplification (CPA) laser was studied, where gain narrowing and self-phase modulation (SPM) are the main mechanisms that modulate the final compressed pulse temporally and spectrally.
Abstract: The propagation and compression of a broadband pulse in a chirped-pulse-amplification (CPA) laser is studied. Gain narrowing and self-phase-modulation (SPM) are the main mechanisms that modulate the final compressed pulse temporally and spectrally. The effect of gain saturation is also investigated. Due to the large chirp of this type of laser pulse, the power gain of the amplifier can be treated as a function of instantaneous frequency to simplify the analysis. Experimental results from an Nd:glass CPA laser system are in good agreement with the theory. Both experimental and theoretical results show that SPM can play an important role in determining the final shape of the compressed pulse, even at relatively low values of the cumulative B-integral, B >
TL;DR: This is to the authors' knowledge the first demonstration of ultrashort pulse shaping using an integrated-optic device and establishes a new application area for integrated wavelength-division-multiplexed devices, namely, for manipulation of coherent, ultrafast time-domain signals.
Abstract: Reshaping of ultrashort optical pulses at 1.53 μm by using an integrated acousto-optic tunable filter is reported. Control of the optical pulse shape is accomplished by adjusting the different radio-frequency electrical signals driving the acousto-optic filter. This is to our knowledge the first demonstration of ultrashort pulse shaping using an integrated-optic device and establishes a new application area for integrated wavelength-division-multiplexed devices, namely, for manipulation of coherent, ultrafast time-domain signals.
TL;DR: In this paper, the authors relate the generation of spectral sidebands to a loss mechanism dependent on the pulse duration and total cavity dispersion, and confirm experimentally using an erbium figure eight laser that the minimum pulse duration is therefore limited by the total dispersion.
Abstract: Generation of spectral sidebands is characteristic of ultrashort soliton all‐fiber lasers. We relate the generation of these sidebands to a loss mechanism dependent on the pulse duration and total cavity dispersion. We confirm experimentally using an erbium figure eight laser that the minimum pulse duration is therefore limited by the total dispersion. Short cavities constructed from low‐dispersion components allow shorter pulses to be obtained, and we demonstrate pulse durations as short as 160 fs.
TL;DR: In this article, a four-wave difference-frequency mixing scheme based on near resonant two-photon excitation of xenon with a femtosecond KrF excimer laser system is used to generate tunable short pulse radiation in the VUV and UV spectral range between 133 and 355 nm with output energies of several microjoules.
Abstract: A four-wave difference-frequency mixing scheme based on near resonant two-photon excitation of xenon with a femtosecond KrF excimer laser system is used to generate tunable short pulse radiation in the VUV and UV spectral range between 133 and 355 nm with output energies of several microjoules. Tunable nanosecond laser radiation in the range from 1905 nm to 185 nm is used. At excimer laser wavelengths of 193 nm (ArF), 308 nm (XeCl) and 350 nm (XeF), the process has been used to generate high power short pulse radiation by double-pass amplification in an additional excimer laser discharge. Output energies of 1.9, 3.0, and 2.8 mJ, respectively, have been obtained so far at pulse durations in the range of 1 ps. Nonlinear susceptibilities for the difference-frequency mixing process are calculated using a stationary susceptibility formalism and compared to experimental values. >
TL;DR: It is shown, both analytically and numerically, that stable double:-humped solitary-wave solutions potentially can be used for transmission and clarifies previous problems with the existence of single-humped localized solitary waves.
Abstract: The problem of nonlinear pulse propagation in optical fibers near the zero dispersion point is investigated. It is shown, both analytically and numerically, that stable double:-humped solitary-wave solutions potentially can be used for transmission. The results clarify previous problems with the existence of single-humped localized solitary waves, i.e., fundamental solitons, which are forbidden in the strict mathematical sense
TL;DR: In this article, an analytical expression for the temporal and radial intensity distributions in the focal plane was found for ultrashort pulse propagation through a lens, a grating, and a slit.
Abstract: Wave optical studies have been made for ultrashort pulse propagation through a lens, a grating, and a slit. The intensity distribution of an ultrashort pulse was calculated in the vicinity of the focal point of a lens. Analytical expression was found for the temporal and radial intensity distributions in the focal plane. For the case of a grating, the pulse front becomes curved far away from the grating and there is a time difference between the edges of the pulse. An analytical form was obtained for both the pulsewidth and the shape of the pulse front. For the case of a slit, calculations were made for a short pulse with tilted pulse front based on the Fraunhofer diffraction theory. A small, additional pulse appears behind the slit, which is off by the angle of the pulse front tilt from the direction of the original propagation. This pulse was predicted by the boundary wave theory. For white light illumination behind the slit, no interference can be seen at the maximum of the intensity; the interference pattern diverges from the maximum of the intensity.
TL;DR: It is demonstrated how optical pulse trains generated through active mode locking can propagate strictly linearly over many thousands of kilometers of dispersive fiber without significant pulse broadening.
Abstract: We demonstrate how optical pulse trains generated through active mode locking can propagate strictly linearly over many thousands of kilometers of dispersive fiber without significant pulse broadening. The technique relies on the highly coherent modes that constitute a mode-locked pulse. The generated optical pulses are recreated at certain distances given by the fiber dispersion and the pulse repetition rate.
TL;DR: Third-order dispersion in femtosecond solid-state lasers can induce a resonant transfer of energy from the mode-locked pulse into a dispersive background, and the presence of intensity-dependent self-amplitude modulation can compensate for this loss.
Abstract: Third-order dispersion in femtosecond solid-state lasers can induce a resonant transfer of energy from the mode-locked pulse into a dispersive background. The presence of intensity-dependent self-amplitude modulation can compensate for this loss. A condition for energy balance between these two effects is evaluated and related to the stability of femtosecond pulse generation.
Patent•
15 Jul 1993
TL;DR: In this article, an optically driven interactive Q-switch that responds to a short pulse of light, for example from external light-emitting diodes (LEDs) or diode lasers, is provided for producing an output laser pulse from electronic energy stored in a laser medium.
Abstract: An optically driven interactive Q-switch, ie, a Q-switch that responds to a short pulse of light, for example, from external light-emitting diodes (LEDs) or diode lasers, is provided for producing an output laser pulse from electronic energy stored in a laser medium Q-switching is thus achieved on demand by electrically pulsing the light source to produce a pulse of light directed onto a Q-switch medium in the laser cavity Electronic control of the light pulse from the external source will thus provide not only efficient Q-switching frequency but also independent control of output laser pulse width with a fast rise time for each output laser pulse
TL;DR: The effect of two-photon absorption on the amplification of ultrashort optical pulses is studied theoretically by solving a generalized nonlinear Schrodinger equation.
Abstract: The effect of two-photon absorption on the amplification of ultrashort optical pulses is studied theoretically by solving a generalized nonlinear Schrodinger equation. An input pulse can be simultaneously amplified and compressed, although the compression factor is smaller in the presence of two-photon absorption. The amplified pulse evolves toward a chirped soliton that is the solitary-wave solution of the underlying propagation equation. It can split into several chirped solitons whose number, width, and peak power depend on the amplifier parameters
TL;DR: In this paper, the authors report stable operation of a flashlamp-pumped LiSrAlF 6 : Cr 3+ regenerative amplifier for femtosecond pulses using chirped pulse amplification.
TL;DR: In this article, a detailed numerical study is performed of the dynamics of optical pulse compression in an additive pulse mode-locking configuration consisting of an erbium-doped fiber laser coupled to a nonlinear optical fiber.
Abstract: A detailed numerical study is performed of the dynamics of optical pulse compression in an additive pulse mode-locking configuration consisting of an erbium-doped fiber laser coupled to a nonlinear optical fiber. Pulse evolution is treated by the use of an extended nonlinear Schrodinger equation incorporating a gain-and-loss term in the active fiber laser and a loss term for the nonlinear fiber, which forms the nonlinear auxilliary cavity. To treat ultrashort optical pulses with durations of less than 100 fs, we have considered third-order dispersion and self-frequency shift. On the basis of extensive numerical simulations of the all-fiber coupled-cavity configuration, a stable operating range for pulse compression is identified. It is shown that a variety of less-desirable dynamical evolutions, including pulse splitting, are obtained under other operating conditions.
Patent•
16 Mar 1993
TL;DR: In this article, an electro-optic deflector scans a light pulse through an optical system which provides a varying optical path length that is a function of deflection angle, each having a different transit time to some image plane at the output.
Abstract: A system that modifies a pulsed or continuous wave light beam of arbitrary frequency bandwidth facilitating optical pulse synthesis and pulse compression while largely conserving light energy. An electro-optic deflector scans a light pulse through an optical system which provides a varying optical path length that is a function of deflection angle. The input light pulse is temporally segmented in incremental or differential portions, each of which has a different transit time to some image plane at the output. The temporal portions are then recombined at the output to produce a new optical signal.
TL;DR: In this article, a technique called frequency resolved optical gating (FROG) is proposed to measure the full intensity and phase of a single femtosecond laser pulse, which is easy to implement and provides an output that graphically displays the instantaneous frequency and time of the pulse.
Abstract: We report and demonstrate a new technique to measure the full intensity and phase of a single femtosecond laser pulse. The technique, which we call 'frequency resolved optical gating' (FROG), is inexpensive, easy to implement, and provides an output that graphically displays the instantaneous frequency vs. time of the pulse. Using almost any instantaneous nonlinear- optical interaction of two replicas of the ultrashort pulse to be measured, FROG involves measuring the spectrum of the signal pulse as a function of delay between the two replicas. The resulting trace of intensity vs. frequency and delay yields an intuitive display of the pulse, similar to the pulse spectrogram. We show that the problem of inverting the FROG trace to obtain the pulse intensity and phase is a two-dimensional phase-retrieval problem. As a result, the FROG trace yields, in principle, an essentially unique pulse intensity and phase. In this work, we show that this is the case in practice, also. In addition, we present an iterative- Fourier-transform algorithm for inverting the FROG trace.
TL;DR: In this article, an analysis is made of the properties of a novel type of optical pulse that may propagate stably at normal dispersion in optical fibers. The stability is achieved by permitting two oppositely phased solitons copropagate with the pulse.
Abstract: An analysis is made of the properties of a novel type of optical pulse that may propagate stably at normal dispersion in optical fibers. The stability is achieved by permitting two oppositely phased solitons copropagate with the pulse. Because the pulse may be described by the ordinary Schrodinger equation, well-known results can be used for obtaining detailed information about, for example, the pulse shape. In particular, the possibility of observing stable excited pulse states is demonstrated.
TL;DR: In this paper, a stack of carefully designed mirrors can be used in conjunction with a femtosecond dye laser to create high-frequency pulse bursts, pulse codes, and discrete-time signals.
Abstract: It is demonstrated that a stack of carefully designed mirrors can be used in conjunction with a femtosecond dye laser to create high-frequency pulse bursts, pulse codes, and discrete-time signals. The repetition rate was 800 GHz. Once built and assembled the device is easily used. Extensions in the development of this device include longer pulse trains, higher operating frequencies, and variable pulse trains. An important extension in both the theory and the construction of this device is the control of the temporal phase of the pulse train. >
TL;DR: In this article, the authors proposed a technique that can lead to simultaneous amplification and compression of picosecond optical pulses by copropagating a weak signal pulse with an intense pump pulse in an optical fiber whose minimum dispersion wavelength is chosen such that it falls between the pump and the signal wavelengths.
Abstract: A novel technique that can lead to simultaneous amplification and compression of picosecond optical pulses is proposed. It consists of copropagating a weak signal pulse with an intense pump pulse in an optical fiber whose minimum-dispersion wavelength is chosen such that it falls between the pump and the signal wavelengths. The pump pulse amplifies the signal pulse through stimulated Raman scattering and at the same time imposes a nearly linear frequency chirp on it through cross-phase modulation. The chirped signal pulse is simultaneously compressed in the anomalous-dispersion regime of the optical fiber as it becomes amplified. Numerical simulations are used to predict the extent of amplification and compression under realistic practical conditions. The signal pulse can be compressed by more than a factor of 10 while it is amplified by 40–50 dB.
TL;DR: In this paper, the frequency shift and the pulse compression of an ultrashort laser pulse propagating in a background plasma wave are unified in the concept of phase modulation of the laser pulse by the plasma wave.
Abstract: The frequency shift and the pulse compression of an ultrashort laser pulse propagating in a background plasma wave are unified in the concept of phase modulation of the laser pulse by the plasma wave. An equation for the evolution of the pulse width is obtained, which is analogous to the energy-conservation equation for a classical particle moving in a potential well. The threshold amplitude of the plasma wave for pulse compression is estimated. Numerical calculations are presented to confirm these results. Laser pulse compression by a plasma wave should be feasible.