Strategies for Reducing the Out-of-Plane Radiation in Photonic Crystal Heterostructure Microcavities for Continuous Wave Laser Applications

The directional optical loss properties of photonic crystal double heterostructure cavities are analyzed using the three-dimensional finite-difference time-domain method. It is found that these high quality factor cavities are dominated by vertical radiation loss, and the addition of heat-sinking lower substrates exacerbates the vertical loss problem. An alternative heterostructure geometry based on introducing a glide-plane is proposed and is shown to significantly reduce out-of-plane radiation. This new geometry is a promising candidate for building chip-scale edge-emitting photonic crystal lasers operating under continuous wave conditions. Alternative vertical slab structures are investigated, and the plausibility of forming electrically injected photonic crystal lasers is discussed.