The first known demonstration of tunable terahertz-wave generation by difference-frequency generation of dual signal-wave quasi-phase-matched optical parametric oscillation was performed with periodically poled LiNbO<sub>3</sub> (PPLN) with a series of gratings. An organic ionic salt, 4-dimethylamino-<i>N</i>-methyl-4-stilbazolium-tosylate (DAST), was used as a nonlinear crystal. A compact terahertz-wave source resulted, and changing the temperature of the PPLN permitted the wavelength to be varied from 120 to 160 <i>μ</i>m. The wavelength could be tuned from 100 to 700 <i>μ</i>m by proper selection of combinations of periodically poled gratings.
© 2000 Optical Society of America
(190.2620) Nonlinear optics : Harmonic generation and mixing
(190.4410) Nonlinear optics : Nonlinear optics, parametric processes
(190.4970) Nonlinear optics : Parametric oscillators and amplifiers
(230.4320) Optical devices : Nonlinear optical devices
(260.3090) Physical optics : Infrared, far
Kodo Kawase, Takaaki Hatanaka, Hidenori Takahashi, Koichiro Nakamura, Tetsuo Taniuchi, and Hiromasa Ito, "Tunable terahertz-wave generation from DAST crystal by dual signal-wave parametric oscillation of periodically poled lithium niobate," Opt. Lett. 25, 1714-1716 (2000)