Abstract-Frequency-agile injection-seeded terahertz-wave parametric generation

Yoshikiyo Moriguchi, Yu Tokizane, Yuma Takida, Kouji Nawata, Shigenori Nagano, Manabu Sato, Taiichi Otsuji, and Hiroaki Minamide

https://www.osapublishing.org/ol/abstract.cfm?uri=ol-45-1-77

An injection-seeded terahertz (THz)-wave parametric generator (is-TPG) enables access to low-frequency fingerprints of molecules in the THz frequency region. However, its conventional scan repetition rate (SRR) is limited below 1 Hz. Thus, in this Letter, we propose an electrically controlled tuning system for the is-TPG, which provides high-speed scanning and random hopping agility. We achieved rapid THz frequency scanning on a pulse-by-pulse basis by employing a gain-switched laser diode and a micro-electromechanical system tunable vertical-cavity surface-emitting laser as the pump and seed lasers. A THz spectrum was acquired with a 10 times higher SRR of 10 Hz for the 1.6–3 THz range with a sampling resolution of 4.6 GHz.

© 2019 Optical Society of America

Abstract-High-average and high-peak output-power terahertz-wave generation by optical parametric down-conversion in MgO:LiNbO3

Applied Physics Letters

Yoshikiyo Moriguchi,  Yu Tokizane, Yuma Takida, Kouji Nawata,   Taizo Eno, Shigenori Nagano,  Hiroaki Minamide,

Schematic of the experimental setup for THz-wave generation at a pulse repetition frequency of 100 kHz. ISO, isolator; PBS, polarization beam splitter; FR, Faraday rotator; and HWP, half-wave plate.

https://aip.scitation.org/doi/abs/10.1063/1.5046126

A widely tunable terahertz (THz)-wave generation that has a high repetition rate and a narrow line width is demonstrated in this paper by injection-seeded THz-wave parametric generation (is-TPG) in a MgO:LiNbO3 crystal. By pumping the crystal using a passively Q-switched neodymium-doped yttrium vanadate microchip laser with a time duration of 140 ps and an average power of up to 5 W, a THz-wave output with an average output power of 30 μW, a peak power of 4 W, a pulse duration of 73 ps, and a pulse-repetition frequency of 100 kHz is obtained. To prevent laser damage and photorefractive damage to the crystal, the constraints on the pumping condition of the MgO:LiNbO3 crystal are experimentally studied by changing the pumping parameters. As a result, we achieved the stable generation of the THz-wave signal in the 100 kHz regime. Moreover, we performed THz-wave imaging by using the developed is-TPG source. The obtained THz image indicated that the developed system has a good stability over long periods of time.