Selective laser etching for micromachined glass micro-optics

The micromachining of glass using laser-based processes such as selective laser etching (SLE) has been shown to be well suited for the fabrication of highly precise three-dimensional glass microstructures of virtually arbitrary shape. However, the machined surfaces are generally of insufficient quality to allow their use as refractive optics primarily due to roughness on various spatial frequency scales. We show how an optimization of the SLE writing process, coupled with post-etch thermal, laser, or mechanical polishing processes, can yield optical-quality glass surfaces yield very low roughness coupled with excellent shape fidelity. Optical characterization, including modulation transfer function and imaging measurements, of test aspheric micro-lenses fabricated using these processes shows that these micromachined components demonstrate sufficient optical performance for them to be beneficially employed in optical microsystems.