Recent developement of terahertz wave generation

History and recent developments of terahertz devices utilizing lattice and molecular vibrations are presented. They are semiconductor Raman oscillator and amplifier, parametric generators of terahertz wave using polariton-phonons in dielectrics and semiconductors. We also present the recent advancements in the fabrication and performance of terahertz electronics devices: ISIT and ZTUNNETT diode. They are fabricated with molecular layer epitaxy (MLE), which is the most advanced nanotechnology having atomic accuracy.