Nitride-based lasers: advances in cavity design

Unique constraints encountered in the III-N semiconductor system, such as a lack of cleaving planes and resistance to wet etchants, make conventional approaches to the fabrication of laser diodes difficult to implement, and result in the need for novel cavity designs. Improvements in in-plane cavities include etching facets using a focused ion beam and the incorporation of gratings to decrease losses associated with poor mirrors. Towards the fabrication of an electrically pumped VCSEL, the issue of the bottom mirror can be addressed by the use of dielectric mirrors, and either the removal of the sapphire substrate or its incorporation into the cavity by using a curved backside mirror. This paper will review recent developments in these areas at UC Santa Barbara.