Showing papers by "Gerard Mourou published in 1980"

A picosecond jitter streak camera

Abstract: A light‐activated silicon switch is used to sweep a picosecond‐resolution streak camera with less than 2 ps of shot‐to‐shot zero‐time fluctuation. This temporal accuracy allows shot accumulation leading to increased signal‐to‐noise ratio and further increase in timing accuracy. Subpicosecond accuracy is demonstrated and is used to time picosecond transients.

High-power phosphate-glass laser system: design and performance characteristics

Abstract: A one-beam prototype of a large twenty-four-beam phosphate-glass laser system has been built and tested. Basic design characteristics include Nd-doped phosphate glass, rod amplifiers up to 90-mm diam, the propagation of a circularly polarized beam, extensive spatial filtering and imaging, and the use of large-aperture Pockels cells. The prototype system has demonstrated focusable power in excess of 750 GW/beam at 50-psec full width at half-maximum (FWHM) pulse duration and has delivered 165 J of focusable energy in a 500-psec (FWHM) pulse. Maximum beam brightness has been measured to be 4 × 1019 W/cm2 · sr at a firing rate of 2 shots/hr. Peak-to-background energy contrast of 108 has been achieved with this system. A detailed description of the system design and performance is presented.

Methods and apparatus for generating microwave pulses and for the measurement and control thereof

Abstract: Picosecond duration microwave pulses are generated used a laser activated semiconductor switch. High voltages are switched with picosecond rise time and result in the establishment of microwave pulses of frequency spectrum commensurate with the rise time of the voltage and wave guide parameters of a wave guide in which the switch is disposed. The activating light pulse is synchronous with the microwave pulse. A system, including an antenna and radar receiver, is responsive to the light pulse and return signals from a target on which the microwave pulse is incident. Reflection measurements of the microwave pulses from a body of semiconductor material which is optically excited by the light pulses relatively delayed between the generation of successive microwave pulses, indicate the duration of the microwave pulses.

Light activated switching by the avalanche effect in semiconductors

Abstract: A body of semiconductor material is biased with multi-kilovolt voltage to establish an electric field approaching the dielectric breakdown field for the semiconductor material. Low level optical energy, such as a laser pulse in the nano-joule range produces free carriers in the semiconductor which multiply in the presence of the electric field to produce avalanche conduction through the semiconductor body thereby switching the multi-kilovolt voltage in precise timed (picosecond) relationship with the application of the optical energy and with high switching or turn on sensitivity.

Laser system using organic dye amplifier

Abstract: A laser system generates high energy ultra-short pulses using a dye cell amplifier driven by ultra-short pulses from a dye laser and pumped by pump pulses from a laser amplifier. The laser amplifier and dye laser are synchronously driven and pumped by the same laser such that the signal pulse from the dye laser arrives at the dye cell amplifier immediately upon the completion of population inversion therein in response to the pump pulse. Efficient high-power, ultra-short laser pulses are obtained from the dye amplifier, since amplified spontaneous emission (ASE) is avoided. Doubler crystals are used to provide the pump pulses to the dye laser from the common driver laser and to provide pump pulses from the laser amplifier to the dye cell amplifier at the proper wave length for the materials used therein. This system is tunable by selecting appropriate dyes for the dye laser and dye cell amplifier and/or tuning elements within the dye laser cavity.

Optoelectronic Switching in the Picosecond Time Domain and Its Applications

Abstract: The laser-activated photoconductive switch [l–4] allows generation of picosecond risetime electrical pulses that are in picosecond synchronism with optical pulses. The availability of such a driver has led to a number of applications that include ultrafast active pulse shaping [5], jitter- free streak camera operation [6], active pre-pulse suppression in a laser driven fusion system [7] and more recently the generation of powerful microwave bursts [8].

Synchronization of an Active-Passive Mode-Locked Nd:YAG Laser and a Mode-Locked Argon Ion Laser

Abstract: We report on the synchronization of pulses from an active-passive mode-1ocked Nd:YAG laser [1] to pulses from a mode-locked Ar ion laser. The jitter between the laser pulses was 18 ps (root mean square) with maximum deviations of ±30 ps over 18 shots. The addition of a synchronously pumped dye laser [2] to the YAG-Ar system would offer a picosecond tunable laser well synchronized to a high-power, high-energy laser. The low-energy dye pulses could also be amplified in dye cells pumped by the synchronous pulses from the mode-locked YAG laser. Applications include picosecond chemistry and laser fusion experiments.