Heat and thermodeformation characteristics of laser mirrors based on powder and felt porous structures cooled by dielectric and liquid metal heat carriers are theoretically investigated. In the case of the heat carriers considered, it is possible to widely vary the regimes of intense heat mass transfer in porous heat exchangers of laser mirrors, whereas use of liquid metal cooling with porous structure fabricated from low coefficient thermal expansion material opens new possibilities in development of especially accurate reflectors with very high optical damage thresholds.

The phenomena of the thermoelastic behavior of materials under powerful, high-repetition-rate laser radiation are discussed. An analysis is based on the Duamel integrals for the thermo-stress characteristics which correspond to CW and high-repetition-rate laser irradiations. Relationships for the upper-level laser intensities which are connected with admissible elastic surface distortion, plastic flow of the material, fatigue distributions, and melting of the surface layer are calculated.