Micro-electro-mechanical focusing mirrors

Novel surface-micromachined focusing mirrors have been designed, fabricated, and tested. The mirrors are constructed from concentric rings of polysilicon and gold, and connected by thin bridges of polysilicon. The outer ring of the mirror is lifted out of the plane of the substrate using thermal actuators to change the mirror´s focal length. The focal lengths for 1 mm diameter mirrors have been driven over the range of 7.39 mm to 14.36 mm at frequencies beyond 120 Hz. The mirror may be able to correct both pincushion and barrel distortion. Applications for this mirror include shaping laser spots for laser radars and holographic data storage, and dynamic focusing onto photodetectors for communication systems