SOFT DIAPHRAGM FOR LASERS Russian patent published in 2000 - IPC

FIELD: laser optics; solid-state and gas lasers for laser fusion technology. SUBSTANCE: soft diaphragm built around dish with two windows interconnected through sealed joint by means of spacer ring with holes which forms casing has optically transparent insert (refraction index n_i) in the form of convex-concave meniscus with spherical or aspherical surfaces placed between windows with two liquid- filled clearances between them. Only one clearance between window and convex surface of meniscus is filled with liquid (refraction index n_l1) absorbing radiation from laser beam of wavelength λ incident on dish; second clearance is filled with liquid having refraction index n_l2 that does not absorb laser radiation. Thickness of absorbing liquid layer increasing as function of dish radius r from its axis to periphery smooths down (anodizes) flow section of dish obeying desired law with contrast K in the range of 10²-10⁶. Differences between refraction indices Δn₁ and Δn₂ of insert and liquid Δn₁= n_i-n_l1 and Δn₂= n_i-n_l2, respectively, are chosen are chosen so as to ensure that maximal deflection angle ϕ(a) of beam incident on dish periphery at r = a is within diffraction angle ϕ(a)<1,22λ/2a for dish aperture diameter 2a. Dish components may be made of various optical materials and may use various working liquids with permissible deviation of their refraction indices Δn < 0,1. EFFECT: improved stability at temperature fluctuations within several degrees. 2 cl, 3 dwg