The objective of this program is to understand the fundamentals governing vertical cavity emitters and cavity polaritons leading to attunement of electrically pumped microcavity lasers and polariton lasers on nonpolar m-plane and semipolar GaN. The intellectual merit is in demonstrating a new type of gain medium and advancing microcavity technologies by developing a model system using nitride materials with large exciton binding energies, improved optical matrix elements and high hole concentrations in the nonpolar and semipolar orientations. Developing room temperature low threshold polariton lasers will require integration of high reflectivity GaN-based bottom and dielectric top reflectors, high quality nitride epitaxial heterostructures and quantum wells, and efficient contact layers and active region heterostructures supporting uniform carrier injection while preserving the strong exciton-photon coupling state. The broader impacts are the advancement of materials science and microcavity device technologies for the development of a new type of laser with significantly lower threshold compared to the vertical cavity surface emitting lasers and in providing an ideally suited multidisciplinary research environment for educating graduate and undergraduate students in the fundamentals of cutting-edge semiconductor optoelectronics and microcavity physics. The transformative applications include optical logic elements operating at much lower power levels compared to conventional Si-based electronics for ultrafast optical computing and on-chip communications with significant energy savings and therefore reduced carbon emissions. Undergraduate students, recruited through existing summer research programs, will be included in this research and educational infrastructure will be enhanced by web-based efforts and by incorporating the fundamental discoveries into the graduate curriculum.