Possibility of using structures with open pores in construction of cooled laser mirrors

A theoretical proposal is made and an experimental demonstration is reported of the desirability of using structures with open pores in the construction of cooled laser mirrors with a separating layer a few microns thick. The aim is to increase the optical damage threshold of the mirror surfaces. It is reported that the thermal deformation of a water-cooled mirror at the center of the illuminated zone ~50 mm in diameter is ~λ /30, where λ =10.6 μ for a maximum steady-state heat flux of ~500 W/cm². The maximum rate of heat removal per unit surface area is about 2.5 kW/cm².