Compact and stable high-repetition-rate terahertz generation based on an efficient coaxially pumped dual-wavelength laser.

A compact and stable terahertz (THz) source is demonstrated based on difference frequency generation (DFG) pumped by an efficient dual-wavelength acousto-optic (AO) Q-switched solid-state Nd:YLF laser with composite gain media (a-cut and c-cut) in the coaxial pumping configuration. Optimal power ratio and pulse synchronization of the orthogonal polarized 1047/1053 nm dual-wavelength laser could be realized by varying the pump focusing depth and/or pump wavelength. The total power of 2.92 W was obtained at 5 kHz pumped by 10-W laser-diode power at 803 nm. Such an efficient dual-wavelength laser demonstrated good stability and inconspicuous timing jitter benefiting from the suppressed gain competition between two resonating wavelengths. An 8-mm-long GaSe crystal was employed to generate THz waves at 1.64 THz by DFG and the maximum THz average output power was about 0.93 μW. This compact coaxial pumping method can be extended to all kinds of neodymium (Nd) doped laser crystals to produce different dual-wavelength lasers for various THz wavelength generation, which have good prospects for portable and costless applications like imaging, non-destructive inspection, etc.

[1]  E. Chicklis,et al.  Compact Fiber-Pumped Terahertz Source Based on Difference Frequency Mixing in ZGP , 2007, IEEE Journal of Selected Topics in Quantum Electronics.

[2]  Wei Shi,et al.  Efficient, tunable, and coherent 0.18-5.27-THz source based on GaSe crystal. , 2002, Optics letters.

[3]  W. Shi,et al.  Widely-tunable high-repetition-rate terahertz generation in GaSe with a compact dual-wavelength KTP OPO around 2 μm. , 2016, Optics express.

[4]  Konstantin L. Vodopyanov,et al.  New dispersion relationships for GaSe in the 0.65–18 μm spectral region , 1995 .

[5]  T. L. Huang,et al.  Synchronized self-mode-locked 1061-nm and 1064-nm monolithic Nd:YAG laser at cryogenic temperatures with two orthogonally polarized emissions: generation of 670 GHz beating. , 2016, Optics express.

[6]  K. Kawase,et al.  Tunable terahertz-wave generation from DAST crystal by dual signal-wave parametric oscillation of periodically poled lithium niobate. , 2000, Optics letters.

[7]  Junhao Chu,et al.  Intensive terahertz emission from GaSe0.91S0.09 under collinear difference frequency generation , 2013 .

[8]  W. Shi,et al.  Compact High-Repetition-Rate Monochromatic Terahertz Source Based on Difference Frequency Generation from a Dual-Wavelength Nd:YAG Laser and DAST Crystal , 2017 .

[9]  M M Fejer,et al.  Intracavity terahertz-wave generation in a synchronously pumped optical parametric oscillator using quasi-phase-matched GaAs. , 2007, Optics letters.

[10]  W. Shi,et al.  Optically pumped terahertz sources , 2017 .

[11]  C. Joshi,et al.  High-power tunable, 0.5-3 THz radiation source based on nonlinear difference frequency mixing of CO 2 laser lines , 2007 .

[12]  Atsushi Sato,et al.  Efficient Terahertz-Wave Generation Using a 4-Dimethylamino-N-methyl-4-stilbazolium Tosylate Pumped by a Dual-Wavelength Neodymium-Doped Yttrium Aluminum Garnet Laser , 2012 .

[13]  Jinjun Wang,et al.  A triple-exposure color PIV technique for pressure reconstruction , 2017 .

[14]  Xiaodong Mu,et al.  Singly resonant optical parametric oscillator based on adhesive-free-bonded periodically inverted KTiOPO4 plates: terahertz generation by mixing a pair of idler waves. , 2012, Optics letters.

[15]  O. Krokhin,et al.  Coherent Thz repetitive pulse generation in a GaSe crystal by dual-wavelength Nd:YLF laser , 2015 .

[16]  Yujie J. Ding,et al.  Investigation of terahertz generation from passively Q-switched dual-frequency laser pulses. , 2011, Optics letters.

[17]  W. Shi,et al.  Widely Tunable High-Repetition-Rate Terahertz Generation Based on an Efficient Doubly Resonant Type-II PPLN OPO , 2016, IEEE Photonics Journal.

[18]  Wei Shi,et al.  Single-frequency terahertz source pumped by Q-switched fiber lasers based on difference-frequency generation in GaSe crystal. , 2007, Optics letters.

[19]  Yujie J. Ding,et al.  Compact and portable terahertz source by mixing two frequencies generated simultaneously by single solid-state laser , 2010, CLEO: 2011 - Laser Science to Photonic Applications.

[20]  W. Shi,et al.  Efficient parametric terahertz generation in quasi-phase-matched GaP through cavity enhanced difference-frequency generation , 2011 .

[21]  Yujie J. Ding.  Progress in terahertz sources based on difference-frequency generation [Invited] , 2014 .