Tuesday, February 10, 2015

Abstract-Energy scaling of terahertz-wave parametric sources

Energy scaling of terahertz-wave parametric sources

Guanqi Tang, Zhenhua Cong, Zengguang Qin, Xingyu Zhang, Weitao Wang, Dong Wu, Ning Li, Qiang Fu, Qingming Lu, and Shaojun Zhang  »View Author Affiliations
Optics Express, Vol. 23, Issue 4, pp. 4144-4152 (2015)

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Terahertz-wave parametric oscillators (TPOs) have advantages of room temperature operation, wide tunable range, narrow line-width, good coherence. They have also disadvantage of small pulse energy. In this paper, several factors preventing TPOs from generating high-energy THz pulses and the corresponding solutions are analyzed. A scheme to generate high-energy THz pulses by using the combination of a TPO and a Stokes-pulse-injected terahertz-wave parametric generator (spi-TPG) is proposed and demonstrated. A TPO is used as a source to generate a seed pulse for the surface-emitted spi-TPG. The time delay between the pump and Stokes pulses is adjusted to guarantee they have good temporal overlap. The pump pulses have a large pulse energy and a large beam size. The Stokes beam is enlarged to make its size be larger than the pump beam size to have a large effective interaction volume. The experimental results show that the generated THz pulse energy from the spi-TPG is 1.8 times as large as that obtained from the TPO for the same pumping pulse energy density of 0.90 J/cm2 and the same pumping beam size of 3.0 mm. When the pumping beam sizes are 5.0 and 7.0 mm, the enhancement times are 3.7 and 7.5, respectively. The spi-TPG here is similar to a difference frequency generator; it can also be used as a Stokes pulse amplifier.
© 2015 Optical Society of America

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