Showing papers by "Gerard Mourou published in 1982"
TL;DR: In this paper, the authors report the construction of a sensitive electro-optic sampling system for the measurement of ultrafast electrical transients, which has a temporal resolution of lessthan 4 ps (over 100 GHz bandwidth).
Abstract: We report the construction of a sensitive electro‐optic sampling system for the measurement of ultrafast electrical transients. This system has a temporal resolution of lessthan 4 ps (over 100‐ GHz bandwidth), better than 50‐μV sensitivity and potential for a temporal resolution reaching the single picosecond. Demonstrated applications are ultrafast photodetector response characterization and time resolved photoconductivity.
369 citations
TL;DR: In this article, a photoelectron pulse generated by a streak camera has been used to probe a thin film of aluminum producing a diffraction pattern representative of its lattice structure, which makes possible the investigation of structural phase transitions in the picosecond time domain.
Abstract: A picosecond photoelectron pulse generated by a streak camera has been used to probe a thin film of aluminum producing a diffraction pattern representative of its lattice structure. Because this photoelectron pulse is in picosecond synchronism with the optical pulse, this technique will make possible the investigation of structural phase transitions in the picosecond time domain.
125 citations
TL;DR: In this article, a synchronously-pumped cw dye laser using a dye medium composed of a mixture of rhodamine 6G and a fast recovery saturable absorber, DQOCI, was used.
74 citations
TL;DR: In this article, the required trigger energy from the laser was ⩾ 35 nJ; the timing jitter was ε ± 150 ps; and the trigger energy was used to switch 4 kV pulses into 50 Ω with < 1 ns rise time.
Abstract: Bulk Cr:GaAs in a sparkgap‐type arrangement has switched 4 kV pulses into 50 Ω with <1 ns rise time. The required trigger energy from the laser was ⩾ 35 nJ; the timing jitter was ⩽ ±150 ps.
26 citations
Patent•
16 Feb 1982TL;DR: In this article, the temporal shape of optical pulses is measured over a wide dynamic range, for example, 10 orders of magnitude, by passing an optical signal corresponding to the autocorrelation function of the optical pulses through a variable attenuation filter.
Abstract: The temporal shape of optical pulses is measured over a wide dynamic range, for example, 10 orders of magnitude, by passing an optical signal corresponding to the autocorrelation function of the optical pulses through a variable attenuation filter, the position of which is a function of the attenuation. By plotting the attenuation of the filter in terms of the position thereof, against the duration of the temporal overlap of the pulses in a mixing crystal which produces the optical signal corresponding to the autocorrelation function, the temporal shape of the pulses is displayed.
14 citations
11 citations
Patent•
14 May 1982TL;DR: In this paper, electron bursts are produced in response to a train of sub-picosecond optical pulses, and the bursts are deflected in accordance with the amplitude of the successive portions of the signal and translated into spots of light, as on a phosphor screen.
Abstract: Electrical signals are measured (analyzed and displayed) with picosecond resolution and sensitivity in the microvolt (less than 100 microvolts) range by electron-optically sampling the signal. Sampling electron bursts are produced in response to a train of subpicosecond optical pulses. A beam of these electron bursts samples successive portions of the signal as it is transmitted as a travelling wave along deflection plates which act as a transmission line. The bursts are deflected in accordance with the amplitude of the successive portions of the signal and translated into spots of light, as on a phosphor screen. The deflection is significantly less than the diameter of the spot. The deviation of the spot with respect to the position thereof in the absence of the signal on the deflection plates is translated into a difference output. The signal to be analyzed is generated, synchronously with the optical pulses, to propagate along the deflection plates in variably delayed relationship therewith. The signal is optically-induced using a separate beam of the optical pulses which is desirably chopped into optical pulses. The difference output is processed, preferably by a lock-in amplifier and signal averager; the lock-in amplifier being synchronized with the chopping of the beam into the optical pulses, and displayed on a time base synchronous with the variable delay of the optical pulses. Accordingly, the signal is displayed on an expanded time scale for measurement and other analysis.
10 citations
23 Apr 1982
TL;DR: The generation of high power electrical pulses that are in picosecond synchronism with optical pulses using laser-induced photoconductivity in high resistivity semiconductors has resulted in a number of applications as discussed by the authors.
Abstract: The generation of high power picosecond risetime electrical pulses that are in picosecond synchronism with optical pulses using laser-induced photoconductivity in high-resistivity semiconductors) has resulted in a number of applications. These include jitter-free streak camera operation, picosecond active pulse shaping, active prepulse suppression, and more recently the generation of picosecond microwave bursts.© (1982) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
3 citations
01 Jan 1982
TL;DR: In this paper, Auston1 demonstrated a sampling technique in amorphous semiconductors that can resolve electrical transients as short as 5 to 10 ps, however, the ultimate resolution of that system is constrained by a material recovery time of approximately 10 ps.
Abstract: With the advent of picosecond photodetectors, photoconductive switches and other ultrafast devices, the need has arisen for a measurement system capable of characterizing small electrical signals with picosecond accuracy. Techniques for measuring ultrafast electrical signals to date have limitations in their use. Sampling oscilloscopes have temporal resolutions limited by their electronic sampling window. This is typically ~ 25 ps. Recently, Auston1 demonstrated a sampling technique in amorphous semiconductors that can resolve electrical transients as short as 5 to 10 ps. However, the ultimate resolution of that system is constrained by a material recovery time of approximately 10 ps.
2 citations
Journal Article•
1 citations
01 Jan 1982
TL;DR: In this paper, the authors investigated the mechanism for recombination and separation of localized carriers in amorphous (a-) semiconductors and found that the mechanism is strongly influenced by studies of sub-bandgap photoluminescence (PL).
Abstract: Current understanding of localized states in amorphous (a-) semiconductors has been strongly influenced by studies of sub-bandgap photoluminescence (PL). In particular, the PL kinetics and temperature dependence bear directly on the mechanisms for recombination and separation of localized carriers. In the prototype chalcogenide glass As2S3 previous experiments have found that the PL is characterized by a large distribution of monomolecular decay times extending from less than ten nanoseconds to several milliseconds [1,2]. It is thought that different recombination processes acount for slow PL decaying in 10.6–10.3 s and fast PL decaying in 2 eV) are required for photoexcitation. A substantial part of the energy difference between emission and excitation has been attributed to a Stokes shift accompanying ‘ocalization at defect sites [1,2,4] or small polaron formation [5].
01 Jan 1982
TL;DR: In this article, a demountable photochron II streak camera tube is used to generate an electron diffraction pattern, inferring that picosecond snap-shots of laser induced structural changes in laser annealing or in the field of surface physics, can now be taken not only with a photo-electron exposure, but also in photoelectron synchronization with the laser induced kinetics.
Abstract: With the exception of picosecond photoelectron switching recently demonstrated, streak camera tubes have been used exclusively as a fast optical and x-ray diagnostic tool. However, some of the most beautiful features of the image converter device used in the streak camera have been only partially exploited with this application. The image converter device produces a temporal and spatial monoenergetic photoelectron replica of the incident optical pulse. This replica is ultimately limited by the temporal and spatial resolution of the particular streak tube employed. Temporal and spatial resolution can be as good as subpicosecond and 100 μm respectively. It is also worth noting that this replica is accurately synchronized with the incident optical pulse. We have used this electron burst to generate an electron diffraction pattern, inferring that picosecond snap shots of laser induced structural changes in laser annealing or in the field of surface physics, can now be taken not only with a picosecond exposure, but also in picosecond synchronization with the laser induced kinetics. In the experiment (Fig.1) a demountable photochron II streak camera tube is used. The Al specimen of 150 Angstroms thickness is located in the drift space 1 cm behind the anode. The diffraction pattern is captured on a phosphor sreen and photographed using an image intensifier with a gain of 3×104 lens coupled to the film.
01 Jan 1982
TL;DR: In this paper, the capabilities of a streak camera with 2 ps jitter were discussed with emphasis upon the advantage of signal averaging, and a versatile system for picosecond detection which facilitates study in a wide range of areas.
Abstract: Since the demonstration of a streak camera with 2 ps jitter,1 we have evolved a versatile system for picosecond detection which facilitates study in a wide range of areas. The capabilities of the system are discussed with emphasis upon the advantage of signal averaging.