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The transport of high-current electron beams from vacuum diodes to the laser chamber of the GARPUN wide-aperture excimer laser was investigated experimentally and theoretically. The processes involving the transport of fast electrons in argon and krypton in a longitudinal magnetic field were also studied. Pumping by counter-propagating electron beams resulted in the deposition of up to 2.1 kJ of energy into the active medium of the laser, which corresponded to a specific excitation power of ~0.8 MW cm-3 with an inhomogeneity of less than 20% over a 12 cm × 18 cm aperture. The efficiency of the energy deposition by electron beams was ~60% and the overall efficiency of the laser pumping system was ~16%.

A description is given of the design of the GARPUN excimer laser module intended for generation of ultraviolet radiation or wide-aperture amplification of short laser pulses. The main parameters of the electron-beam laser-pumping system are given. A detailed discussion is provided of the task of generation of high-current electron beams with a large cross-sectional area and uniform distribution of the current. An analysis of the losses in the system supplying high-voltage pulses to electron accelerators, and also of the losses in the formation and coupling of electron beams to the laser chamber shows that the attained laser-pumping efficiency of ~16% may be increased by a factor of 1.5–2.

A high-power KrF laser system was developed on the basis of a large-aperture excimer laser with electronbeam pumping and injection control by an electric-discharge master oscillator. The spectral brightness of the radiation of line width ~0.1 cm-1, tunable near λ = 248 nm, was ~5 × 1014 W cm-2 sr-1 per cm-1 at a peak power of ~1 GW.

A high-power KrF laser system based on a wide-aperture electron-beam pumped excimer laser `GARPUN' with injection-locking from a discharge pumped narrow-band oscillator has been developed. The laser radiation spectral brightness of approximately 5 X 1014 W/cm2 srad cm-1 with narrow linewidth approximately 0.1 cm-1 tunable near (lambda) equals 248 nm, and the output peak power of approximately 1 GW have been obtained.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The e-beam-pumped KrF laser "GAR-PUN" produces 100 ns pulses with an output energy of ~100 J and peak power ~1 GW in free-running and injection-controlled narrow-band operation.1 In this paper we describe a design of a multistage KrF laser system with an expected output power of 5-10 GW in nanosecond range.

A fine-aperture excimer laser module called the Garpun was constructed with an active region of 18 × 20 × 100 cm dimensions. It was pumped from two sides by high-current electron beams. When the laser was pumped by pulses of 100 ns duration and 2 × 25 A/cm2 current density, the output energy of a F2–Kr–Ar mixture was 60 J and the peak power is 1 GW.

An investigation was made of gasdynamic regimes of interaction of KrF laser radiation pulses with a graphite target in air at various pressures. At radiation flux densities up to 1 GW/cm2 the dominant process was target evaporation initiating a shock wave in the surrounding air. Formation of an optical detonation wave partly absorbing laser radiation was observed at atmospheric pressure.

The thresholds and delay times of the appearance of a light flash near the surfaces of aluminum and graphite targets were determined when these targets interacted with KrF laser radiation pulses. It was found that the flash could be identified with the onset of target evaporation. The evaporation of aluminum began at local inhomogeneities in the form of recesses and led to the formation of microcraters. A study was made of the statistics and morphological structure of typical microcraters.