Tunable MEMS axicon mirror arrays.

Highly aspheric reflective micro-optics for the generation of quasi-nondiffracting beams are of great interest for a wide variety of applications. However, up to now it was impossible to fabricate tunable arrays of these elements. In this Letter, we demonstrate the first array of purely reflective tunable microelectromechanical systems (MEMS) microaxicon mirrors with a conical shape and a continuous surface. The actuation is achieved by thermal expansion in a solid state design and the tuning range allows for large conical angles and is able to form concave as well as convex axicons. The deflection of the mirror surface and the propagation of the resulting quasi-Bessel beams have been characterized to prove the functionality of the device.