Visible photonic crystal VCSELs with high quality output beam

Abstract

We report visible photonic crystal single mode VCSELs with constant and controllable far-field beam divergence angle for all injection currents and temperatures. The beam divergence can be controlled through the etched hole depth. Visible VCSELs are interesting candidates for various sensing and imaging applications [1]. Most of these applications demand a high quality single-mode output beam. A small and stable beam divergence is beneficial for high fiber coupling efficiency, accurate position sensing, homogeneous illumination of displays, or for the projection of sharp images. We report the first proton-implanted red photonic crystal VCSELs, which show excellent optical and electrical characteristics. The maximum single-fundamental-mode output power at room temperature is found to be higher than 1 mW with a Gaussian far-field pattern with a constant divergence angle that can be controlled from 6 to 8 degrees (full angle) independent of injection current or ambient temperature.