Tunable THz-radiation in a ZnGeP2 single crystal pumped by dual-wavelength degenerate optical parametric oscillator

Abstract

A compact continuously tunable dual-wavelength source of radiation based on a diode pumped Nd:AG laser and an intracavity degenerate optical parametric oscillator (IDOPO) was demonstrated for the first time. The generation of two pulses of radiation with mutually orthogonal polarization and a wavelength difference from 0 to 500 nm is realized. The pulse energy reached ~1 mJ with a pulse duration of 10 ns at a repetition rate up to 1 kHz. Terahertz (THz) radiation was obtained using a difference frequency generation DFG in a single crystal ZnGeP2. The tuning range of the THz radiation in the wavelength range ~120–270 µm was realized. The maximum average power of THz radiation achieved in the experiment was ~3.3 nW at a wavelength of λ = 181 µm.