Abstract-Off-axis terahertz parametric oscillator

Yu-Chung Chiu, Tsong-Dong Wang, Po-Cheng Wang, and Yen-Chieh Huang

https://www.osapublishing.org/josab/abstract.cfm?uri=josab-36-1-42

We study an off-axis terahertz (THz) parametric oscillator and show its superior performance over a conventional THz parametric oscillator. Furthermore, by pumping an off-axis lithium-niobate oscillator with a pulsed Nd:YAG laser having an axial-mode spacing matched to the THz oscillator’s mode spacing, we generated an ultra-broad red-shifted frequency comb between 1065 and 1085 nm at the output, which corresponds to a four-octave-spanning THz-frequency comb in the idler spectrum. We also demonstrated a signal-seeded off-axis THz parametric oscillator, which generates 8 nJ narrow-line radiation at 2.1 THz and achieved 46% pump depletion in a 6.5 cm long crystal with only 4 mJ pump energy in a 460 ps pump pulse width. Furthermore, tuning between 3.6 and 4.9 THz for the generated radiation is also demonstrated in this work.

© 2018 Optical Society of America

Abstract-Terahertz parametric generation and amplification from potassium titanyl phosphate in comparison with lithium niobate and lithium tantalate

Ming-Hsiung Wu, Yu-Chung Chiu, Tsong-Dong Wang, Gang Zhao, Andrius Zukauskas, Fredrik Laurell, and Yen-Chieh Huang

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-24-23-25964

We report superior terahertz parametric generation from potassium titanyl phosphate (KTP) over congruent-grown lithium niobate (CLN) and lithium tantalate (CLT) in terms of parametric gain and laser damage resistance. Under the same pump and crystal configurations, the signal emerged first from KTP, 5% Mg-doped CLN, CLN, and then finally from CLT. The signal growth rate in KTP was comparable to that in 5%-Mg-doped CLN, but the signal power from KTP reached a much higher value after all the other crystals were damaged by the pump laser. We further demonstrate seeded terahertz parametric amplification in an edge-cut KTP at 5.74 THz. The THz parametric amplifier (TPA) employs a 17-mm long KTP gain crystal, pumped by a passively Q-switched pump laser at 1064 nm and seeded by a continuous-wave diode laser tuned to the signal wavelength at 1086.2 nm. With 5.8-mJ energy in a 520-ps pump pulse and 100-mW seed signal power, we measured 5-W peak-power THz output from the KTP TPA with 22% pump depletion. In comparison, we measured no detectable THz output power from a similar edge-cut CLN TPA under the same pump power, detection scheme, and crystal configuration, when tuning the seed laser wavelength to 1072.2 nm and attempting to generate a radiation at 2.1 THz.

© 2016 Optical Society of America

Full Article  |  PDF Article