VCSEL With Photo-Aligned Liquid Crystal Overlay

A technological platform for a vertical cavity surface-emitting laser with a tunable polarization is presented. It is achieved by integrating an 850-nm vertical cavity surface-emitting laser chip in a liquid crystal cell that uses photo-alignment to orient the nematic liquid crystal. The vertical cavity surface-emitting laser and the liquid crystal layer can be electrically driven with separate electrodes. We demonstrate that the polarization state of the laser emission can be controlled by applying an appropriate voltage over the liquid crystal layer. The polarization of the emission depends on the emission angle, in particular, for voltages close to the liquid crystal threshold voltage, which is in agreement with expectations from the extended Jones calculus.