Three-dimensional optical focusing systems utilizing stress-induced bending of concave micromirrors

In this study, a three-dimensional optical focusing system utilizing stress-induced bending of concave micromirrors was examined. The shape and thermal effects of micromachined bilayer concave mirrors were first investigated. The characterization of the bilayer concave mirror with different Au distributions was performed to observe out-of-plane deformation. A finite-element model was established to analyze such a deformation. As postprocessing temperature increases, the curvature of the concave mirror increases, resulting in a larger out-of- plane deformation of the concave mirror. Finally, a novel reflective surface-micromachined three-dimensional focusing system was demonstrated. The three-dimensional focusing system comprised two optic fiber guide plates, a Fresnel lens, and a three-dimensional concave mirror. The concave mirror was capable of focusing and collecting light, and could be readily integrated into a micro-optical bench for various optical applications.