VCSEL with finite-size high-contrast metastructure

Abstract

© Copyright 2018 Society of Photo‑Optical Instrumentation Engineers (SPIE). One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this publication for a fee or for commercial purposes, and modification of the contents of the publication are prohibited.High-contrast metastructures like one-dimensional high-contrast gratings (HCGs) are promising to improve the performance of conventional VCSELs, also presenting a basis for new applications. Different from the previous studies where HCGs are always modelled being of infinite size, we studied here the finite-size HCGs, which match the real situation. We observe finite-size HCGs behaving very differently from infinite-size HCGs. The reflectivity of a finitesize HCG strongly depends on the HCG size and the source size. At the same time, the simulation results show, that finite-size HCGs can shape the output beam, and a Gaussian-like reflected wave is typically achieved. Most important the normally incident light is partly redirected to the in-plane direction, showing unidirectional transmission. Monolithically integrated HCG-based optical sensors can be based on this novel effect. An integrable HCG reflector was fabricated with GaInP as the sacrificial layer targeting the application of HCG-VCSEL at 980 nm range. The measured reflectivity agrees well with the calculated reflectivity