High Power, Narrow-Linewidth, and Compact Terahertz Sources for Room Temperature Applications

Abstract

We present the recent progress of room temperature terahertz (THz) sources based on intracavity difference-frequency generation from mid-infrared quantum cascade lasers. The active cores based on the single-phonon resonance scheme are designed with a giant THz nonlinearity. Integrated dual-period distributed-feedback grating is used to purify the THz spectra. Room temperature single-mode operation is obtained from the modal-phase matched THz sources at 3.3–4.6 THz, with a THz power of 65 μW at 4 THz. A wider THz spectral range of 1–4.6 THz is obtained from the Cerenkov phase-matched THz sources, where a maximum power of 32 μW at 2.6 THz is demonstrated. The THz power of Cerenkov device is further improved by epi-down mounting with a high THz power of 215 μW at 3.5 THz. The rapid development renders this type of THz sources promising local oscillators for many astronomical and medical applications.