Terahertz-wave generation from quasi-phase-matched GaP for 1.55μm pumping

Abstract

We have realized a terahertz (THz)-wave source employing difference frequency generation (DFG) from a quasi-phase-matched GaP stack pumped at 1.55μm. We observed THz waves with enhanced power by quasi-phase matching (QPM) in the ⟨110⟩ direction of GaP with a ⟨111⟩ polarization direction for the incidence of two pump lights with the same propagation and polarization directions. We obtained THz-wave power proportional to the product of two pump-light powers due to DFG. We also confirmed that power peaks appeared at around 1 and 2.6THz reflecting the first- and the third-order QPM, respectively.

Ultra-narrow-linewidth continuous-wave THz sources based on multiplier chains

“…Accurate frequency stabilization of the two lasers is necessary in order to obtain a frequency-stable THz wave. As alternative sources, and also to cover higher THz frequencies, quantum cascade laser sources are under intense development [8,10,11], toward compact, efficient sources with significant output power (at mW level). However, so far these sources require cryogenic operation.…”

“…THz spectroscopy has also been performed using sources based on mixing two lasers [1,5] in a nonlinear medium (photomixers [6,9] and nonlinear-optical crystals [7,8]), producing a wave at the difference frequency. Accurate frequency stabilization of the two lasers is necessary in order to obtain a frequency-stable THz wave.…”

CW THz Wave Generation System with Diode Laser Pumping

“…Especially, their second-order nonlinear susceptibilities, χ (2) , are one or two orders of magnitude larger than those of typical second-order nonlinear materials such as LiNbO 3 and KTP [26,27]. Furthermore, their absorption coefficient in the THz region is several times smaller than that of LiNbO 3 [28]. It is well known that, in the anisotropic birefringent crystals, the input pump and signal waves, and , for difference frequency mixing, and the generated THz wave, , are generally all in the same transmission window of the nonlinear crystal.…”

Fabrication and Characterization of GaP Photonic Crystals for Terahertz Wave Application

“…The most THz-wave sources are based on photoconductive antenna, quantum cascade lasers, or non-linear optical effects such as difference frequency generation (DFG), optical parametric oscillation, and optical rectification. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] The DFG can produce tunable, narrow linewidth, and high power THz-waves with ns-pulsed as well as CW operation. 18,19) The THz-waves can be generated at room temperature.…”

“…[7][8][9][10][12][13][14]20) In addition, our previous works have generated THz-waves with bulk GaP crystals under a small-angle non-collinear phase matched DFG condition. [7][8][9] By using the THz wave source, a frequencytunable THz spectrometer has constructed, and the THz spectra of important biomolecules (e.g.…”