Browsing by Author "Zhang, G."

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Comparative study of intracavity KTP-based Raman generation between Nd:YAP and Nd:YAG lasers operating on the F-4(3/2) -> I-4(13/2) transition
(2015-04-20)
Huang, Y. J.
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Chen, Y. F.
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Chen, W. D.
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Zhang, G.
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電子物理學系
Extending the spectral wavelengths of the diode-pumped Nd-doped lasers at 1.3 mu m with the KTP crystal in the intracavity Raman configuration is reported for the first time to the best of our knowledge. A systematic comparison is performed to show that a better optical conversion efficiency for the Nd:YAP/KTP Raman laser could be achieved thanks to the higher peak power and linearly polarized radiation at 1341 nm, whereas up to four Stokes emission lines are generated from the Nd: YAG/KTP Raman laser as a result of the fundamental dual-color operation at 1319 and 1338 nm. The maximum Stokes output power of the developed Nd: YAP/KTP Raman laser reaches 1.04 W under an incident pump power of 16 W and a pulse repetition rate of 10 kHz, corresponding to the diodeto-Stokes conversion efficiency as high as 6.5%. The largest pulse energy and highest peak power are evaluated to be up to 104 mu J and 34.7 kW, respectively. (C) 2015 Optical Society of America
Diode-Pumped Nd:YAP Intracavity Optical Parametric Oscillator Emitting at 1603 nm: Influence of Energy-Transfer Upconversion
(2016-06-01)
Cho, H. H.
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Huang, Y. J.
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Chen, W. D.
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Zhang, G.
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Chen, Y. F.
A diode-end-pumped actively Q-switched Nd:YAP laser at 1080 nm is originally designed to intracavity pump a Potassium Titanyl Phosphate KTiOPO4 (KTP)-based optical parametric oscillator for obtaining the signal wavelength at 1603 nm. Under an absorbed pump power value of 11 W, the maximum average output power at the eye-safe radiation is efficiently generated to be 1.11 W at a pulse repetition rate of 10 kHz. At a pulse repetition rate of 5 kHz, the shortest pulse duration, the largest pulse energy, and the highest peak power are found to be 2.4 ns, 190 mu J, and 67.3 kW, respectively. In addition, the influence of energy-transfer upconversion effect on the capability of power scaling of the developed Nd: YAP fundamental laser is experimentally investigated and theoretically analyzed.
Dual-wavelength eye-safe Nd:YAP Raman laser
(2015-08-01)
Huang, Y. J.
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Chen, Y. F.
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Chen, W. D.
;
Zhang, G.
;
電子物理學系
We report on a diode-pumped, Q-switched intracavity-Raman-shifted Nd-doped yttrium-aluminum-perovskite (Nd:YAP) laser using potassium titanyl phosphate (KTP) or potassium titanyl arsenate (KTA) nonlinear crystals to produce eye-safe radiation. In both cases, we obtained simultaneous laser emission at two wavelengths corresponding to distinct Raman gain peaks and different Stokes orders for the nonlinear crystal used. From the Nd:YAP/KTP laser source, we obtained 3 ns pulses of combined 21 kW peak power at 1478 and 1503 nm. From the Nd:YAP/KTA laser source, we obtained up to 220 mW total average output power, equally split between 1474 and 1480 nm emission lines. (C) 2015 Optical Society of America
Generation of multiple spectral bands in a diode-pumped self-mode-locked Nd:YAP laser
(2016-02)
Huang, Y. J.
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Tzeng, Y. S.
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Cho, H. H.
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Chen, Y. F.
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Chen, W. D.
A single- and multispectral-band diode end-pumped self-mode-locked Nd:YAP laser is originally demonstrated with an intracavity etalon to properly control the gain-to-loss ratios among the intermanifold lines on the F-4(3/2) -> I-4(11/2) transition level. With a pulse repetition rate of 5.07 (3Hz, the shortest pulse durations under the single-spectral-hand operation are achieved to be 11.1 ps at 1073 nm, 10.9 ps at 1080 nm, and 15.1 ps at 1084 nm, respectively. Moreover, the temporal overlapping of the multispectral-band pulses is experimentally found to lead to the generation of an intensity fringe pattern in the autocorrelation trace with the optical-beat frequency reaching several terahertz. A simple mathematical model is developed to elucidate the formation of a train of optical-beat pulses.
High-peak-power large-angular-momentum beams generated from passively Q-switched geometric modes with astigmatic transformation
(2017-12-01)
Chen, Y. F.
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Chang, C. C.
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Lee, C. Y.
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Sung, C. L.
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Tung, J. C.
The criterion of achieving efficient passive Q-switching is analyzed to design an off-axis pumped Nd:YVO4/Cr4+ : YAG laser with a degenerate cavity. Experimental results reveal that pure high-order HG(0,m) or HG(m,0) eigenmodes with the order m between 0 and 14 can be generated, depending on the off-axis displacement along the y axis or the x axis. On the other hand, lasing modes naturally turn into planar geometric modes when the off- axis displacement is larger than the value for exciting the HG(0,m) or HG(m,0) eigenmodes with m > 14. The overall peak powers for high- order eigenmodes or geometric modes can exceed 140 W. Furthermore, the high- order eigenmodes and geometric modes are employed to generate vortex beams with large orbital angular momentum by using an external cylindrical mode converter. Theoretical analyses are performed to confirm experimental results and to manifest the phase structures of the generated vortex beams. (C) 2017 Chinese Laser Press
High-power tunable single- and multi wavelength diode-pumped Nd:YAP laser in the F-4(3/2) -> I-4(11/2) transition
(2013-11-04)
Tzeng, Y. S.
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Huang, Y. J.
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Tang, C. Y.
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Su, K. W.
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Chen, W. D.
We experimentally explore the fluorescent spectrum of the Nd:YAP crystal to manifest the feasibility of tunable single-and multi-wavelength operations in the F-4(3/2) -> I-4(11/2) transition. An intracavity etalon is subsequently exploited to effectively select spectral lines at 1073, 1080, and 1084 nm with the tunabilities of 0.56, 1.13, and 0.1 nm, respectively. We also experimentally obtain multi-wavelength oscillations among various intermanifold lines in the Nd:YAP crystal with the output powers on the order of several watts for each group. Employing the Cr4+:YAG crystal to realize the passively Q-switched operation, the maximum average output powers as high as 2.3 and 3.5 W for 1073 and 1080 nm are obtained. The corresponding pulse energies at 1073 and 1080 nm are up to 177 and 159 mu J, respectively. (C) 2013 Optical Society of America