Formation of a thermal lens in the exit window of a laser due to passage of a giant laser pulse

E. I. Babadzhan, Yu. N. Lokhov, V. S. Mospanov


Abstract: An analysis is made of the dynamics of formation of thermal lens in the exit window of a large-diameter (≤ 1 m) laser due to the passage of a high-power laser pulse of λ = 1 nsec to 10 μsec duration. Expressions are obtained for the optical power of a thermal lens and for the radiation intensity corresponding to the appearance of critical optical distortions in the lens. Numerical estimates, obtained for various exit-window materials in the wavelength range λ = 1.06–10.6 μ, show that optical distortions should be slight for pulses of about 1 nsec duration. When τ is increased, these distortions increase strongly. Catastrophic optical distortions in the exit window may be expected when the threshold of avalanche electron multiplication is exceeded.

UDC: 538.56:535

PACS: 42.60.Nj, 42.80.Em

Received: 28.11.1975

 English version: Soviet Journal of Quantum Electronics, 1976, 6:6, 675–679