SEDL / STP / STP799-EB / STP37229S

Studies of Laser-Produced Damage to Transparent Optical Material in the UV Region and in Crossed UV-IR Beams

Gorshkov, BG
Lebedev Physical Institute of the USSR Academy of Sciences, Moscow,

Epifanov, AS
Lebedev Physical Institute of the USSR Academy of Sciences, Moscow,

Manenkov, AA
Lebedev Physical Institute of the USSR Academy of Sciences, Moscow,

Panov, AA
Lebedev Physical Institute of the USSR Academy of Sciences, Moscow,

Pages: 11    Published: Jan 1983

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Abstract

The values of the damage thresholds of some alkali halide crystals, sapphire and fused quartz at λ = 0.266 μm are presented.

The role of electron avalanche in the damage of real wide-gap dielectrics in the UV region is discussed.

Some peculiarities of the interaction of intense UV radiation with dielectrics (nonlinear absorption, photoionization of impurities, self-focusing and others) are considered.

Experiments on laser damage induced by two synchronous, crossed laser beams with different frequencies (λ¹ = 1.06 μm and λ² = 0.266 μm) are described. This method makes it possible to establish the influence of “seeding” electrons on the development of laser-produced damage, as well as to determine if the damage mechanisms are similar at different frequencies.

In order to record directly and estimate concentrations of the free carriers excited by UV laser radiation, d.c. photoconductivity experiments have been carried out.