Energy scaling of terahertz-wave parametric
sources
Guanqi Tang,
1
Zhenhua Cong,
1
Zengguang Qin,
1
Xingyu Zhang,
1,4
Weitao Wang,
1
Dong
Wu,
1
Ning Li,
1
Qiang Fu,
1
Qingming Lu,
2
and Shaojun Zhang,
3,5
1
School of Information Science and Engineering, and Shandong Provincial Key Laboratory of Laser Technology and
Application, Shandong University, Jinan, 250100, China
2
School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong 250100, China
3
State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong 250100, China
4
xyz@sdu.edu.cn
5
sjzhang@sdu.edu.cn
Abstract: 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/cm
2
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
OCIS codes: (160.3730) Lithium niobate; (190.4410) Nonlinear optics, parametric processes;
(190.4970) Parametric oscillators and amplifiers.
References and links
1. K. Kawase, J. Shikata, and H. Ito, “Terahertz wave parametric source,” J. Phys. D 35(3), R1–R14 (2002).
2. K. Kawase, Y. Ogawa, Y. Watanabe, and H. Inoue, “Non-destructive terahertz imaging of illicit drugs using
spectral fingerprints,” Opt. Express 11(20), 2549–2554 (2003).
3. K. Kawase, M. Sato, T. Taniuchi, and H. Ito, “Coherent tunable THz-wave generation from LiNbO
3
with
monolithic grating coupler,” Appl. Phys. Lett. 68(18), 2483–2485 (1996).
4. K. Kawase, M. Sato, K. Nakamura, T. Taniuchi, and H. Ito, “Unidirectional radiation of widely tunable THz
wave using a prism coupler under nonlinear phase matching condition,” Appl. Phys. Lett. 71(6), 753–755
(1997).
5. K. Kawase, J. Shikata, H. Minamide, K. Imai, and H. Ito, “Arrayed silicon prism coupler for a terahertz-wave
parametric oscillator,” Appl. Opt. 40(9), 1423–1426 (2001).
6. T. Ikari, X. B. Zhang, H. Minamide, and H. Ito, “THz-wave parametric oscillator with a surface-emitted
configuration,” Opt. Express 14(4), 1604–1610 (2006).
7. T. Ikari, R. X. Guo, H. Minamide, and H. Ito, “Energy scalable terahertz-wave parametric oscillator using
surface-emitted configuration,” J. Eur. Opt. Soc. Rapid Pub. 5, 10054 (2010).
8. D. H. Wu and T. Ikari, “Enhancement of the output power of a terahertz parametric oscillator with recycled
pump beam,” Appl. Phys. Lett. 95(14), 141105 (2009).
9. B. Sun, S. X. Li, J. S. Liu, E. B. Li, and J. Q. Yao, “Terahertz-wave parametric oscillator with a misalignment-
resistant tuning cavity,” Opt. Lett. 36(10), 1845–1847 (2011).
10. H. Minamide, S. Hayashi, K. Nawata, T. Taira, J. Shikata, and K. Kawase, “Kilowatt-peak terahertz-wave
generation and sub-femtojoule terahertz-wave pulse detection based on nonlinear optical wavelength-conversion
at room temperature,” J. Infrared Milli. Terahz. Waves 35(1), 25–37 (2014).
Received 22 Dec 2014; revised 31 Jan 2015; accepted 2 Feb 2015; published 10 Feb 2015
23 Feb 2015 | Vol. 23, No. 4 | DOI:10.1364/OE.23.004144 | OPTICS EXPRESS 4144