ASPHERICAL TELESCOPES FOR LASER-AMPLIFIER S IN THE THEORY OF OPTICAL INVERSE PROBLEMS

An approach is developed to provide a framework in which the task of s earching for and selecting the configuration of a two-mirror telescope is formulated as an optical inverse problem: the telescope configurat ion is found from a given amplitude and/or phase distribution of the f ield in the plane of the output mirror aperture. Integral equations ar e obtained for determination of the shape of the telescope mirrors. Th e solutions of this inverse problem are studied in the geometric optic s approximation. A numerical investigation is made of the output radia tion power and of the axial radiation intensity in the far-field zone as a function of the configuration of a telescope amplifier and of the input beam characteristics. The use of an aspherical telescope makes it possible to increase, compared with the spherical configuration, th e output radiation power and the axial power density of the focused be am by optimisation of the number of trips the radiation makes inside t he telescope and of the amplitude distribution of the output radiation .