Fabrication of diffractive optical elements for an integrated compact optical microelectromechanical system laser scanner

Abstract

We describe the microfabrication of a multilevel diffractive optical element (DOE) onto a microelectromechanical system (MEMS) module as a key element in an integrated compact optical-MEMS laser scanner. The DOE is a four-level off-axis microlens fabricated onto a movable polysilicon shuttle. The microlens is patterned by electron beam lithography and etched by reactive-ion-beam etching. The DOE was fabricated on two generations of MEMS components, each of which is briefly described. The compact design of the laser scanner is based on mounting a MEMS module and a vertical cavity surface-emitting laser onto a fused silica substrate that contains the rest of the optical system. The calculated scan range of the system is ±4° with a spot size of 0.5 mm.