Abstract: A laser mirror resistant to thermal distortions produced by radiative heating and/or heating by other processes associated with high power CW lasers. A plurality of rods connect a flexible face portion to a stiff base portion to define an "elastic" arrangement which permits free lateral expansion but resists if not prevents distortion in the form of bending of the face portion. The face portion may be formed1. from a block of heat conductive material which has been deeply slotted from its rear end to define an effectively thin face portion attached to a middle portion of high heat capacity, or2. from a thin plate of heat conductive material cooled from the rear face by either forced convection to, or by nucleate boiling of, a flowing heat transfer media in the middle portion.