Continuous Wave Terahertz Source Photonic Band Engineering

"The terahertz (THz) wave region is an underutilized electromagnetic spectrum in which generation is difficult. The existing THz sources are generated either by large and expensive free electron laser or by pulsed optical radiations. There is an increasedneed for continuous THz wave source of high temporal and spatial coherence. The practical use of THz spectrum requires new laser technology that are also energy efficient and cost effective. Recent progress in photonic band gap engineering holds a promiseof realizing highly efficient coherent THz laser of most cost effective. Although there are several theories predicting efficient photonic band nonlinear optical generations of THz waves, such a feasibility demonstration has not been reported. In thisprogram, AGILTRON and Tufts University propose to demonstrate a continuous wave terahertz parametric oscillator directly pumped by a diode laser using photonic crystal as parametric gain medium. With the engineerable phase matching and enhanced high gainproperties available through photonic crystal, state-of-the-art cw terahertz wave laser is anticipated. The devices have a wide range of "dual use" applications in space communications and in active and passive imaging."