Professor Heritage is conducting research in microphotonics, terahertz bandwidth optics, next generation optical networks, optical microwave interactions and vacuum optoelectonics. Recent developments include MEMS mirror arrays for all optical switching, femtosecond pulse shaping, and miniature broadband time delay scanners. He investigates the impact of physical layer impairments on performance of switched WDM networks. He participates in a UC Davis / SLAC / LLNL project aiming to develop a compact high brightness X-ray source for medical applications and for fundamental studies of ultrafast dynamics of bulk state of matter. His group is developing vacuum photocathodes based on optical gating of arrays of fabricated silicon field emitter tips.