a mems mirror is disclosed having thickness correlated with the intensity profile of an impinging optical beam , so as to reduce moment of inertia of the mems mirror while preserving optical quality of the reflected beam . it is the mirror edges that contribute the most to the moment of inertia , while it is generally the mirror center that contributes the most to a reduction of the quality of an optical beam reflected from the mirror . accordingly , by providing a mirror having laterally varying thickness matched to the local variation of the intensity of the optical beam , the quality of the latter may be preserved while the moment of inertia of the mirror may be significantly reduced . the thickness of mems mirrors may be varied continuously or stepwise ; in one direction or in two mutually orthogonal directions .