Fabrication of Functional Optical Structures Based On Photonic Crystals

We have developed techniques to fabricate photonic crystals within functional semiconductor materials to reflect, polarise, and filter light. These manufacturable structures have now allowed us to define high-contrast polarizing beam-splitters and ultra-small optical cavities, and hold the promise of many exciting new applications. Polarizers with over 820:1 TE/TM transmission ratios have been fabricated by microfabricating gratings through a 1-D multilayer Bragg mirror, thereby forming an in-plane 2-D photonic bandgap crystal. Ultra-small optical cavities have also been defined by perforating very thin InGaAsP/InGaAs membranes with 2-D photonic crystals to define in-plane optical resonators. Here, we will describe the fabrication methods and the observed performance of these devices.