Browsing by Author "Tang, C. Y."

Now showing 1 - 10 of 10

A high-power harmonically self- mode-locked Nd:YVO4 1.34-mu m laser with repetition rate up to 32.1 GHz
(2014-04-01)
Wu, T. W.
;
Tsou, C. H.
;
Tang, C. Y.
;
Liang, H. C.
;
Chen, Y. F.
We develop a practical method to achieve harmonically self-mode-locked operation in a Nd:YVO4 1.34-mu m laser for the generation of high-repetition-rate pulse trains. We exploit a gain medium with partial-reflection coating at the lasing wavelength to introduce effective mode selection. We numerically demonstrate that the coated gain medium can effectively modify the mode spacing of the laser cavity to be the harmonics of the free spectral range of the gain medium when the optical cavity length is adjusted to be commensurate with the optical length of the gain medium. We further employ a coated Nd: YVO4 crystal to realize harmonically mode-locked operation with a highest repetition rate of up to 32.1 GHz. At a pump power of 11.5 W, the average output power of 2.3 W is generated with a pulse duration as short as 5.7 ps. The locking range for the cavity length is also experimentally explored.
An energy adjustable linearly polarized passively Q-switched bulk laser with a wedged diffusion-bonded Nd:YAG/Cr4+:YAG crystal
(2015-03-23)
Cho, C. Y.
;
Cheng, H. P.
;
Chang, Y. C.
;
Tang, C. Y.
;
Chen, Y. F.
An energy adjustable passively Q-switched laser is demonstrated with a composite Nd:YAG/Cr4+:YAG crystal by applying a wedged interface inside the crystal. The theoretical model of the monolithic laser resonator is explored to show the energy adjustable feature with different initial transmissions of the saturable absorber at the horizontal axis. By adjusting the pump beam location across the Nd: YAG crystal, the output pulse energy can be flexibly changed from 10.9 mu J to 17.6 mu J while maintaining the same output efficiency. The polarization state of the laser output is found to be along with the polarization of the C-mount pump diode. Finally, the behavior of the multi-transverse-mode oscillation is also discussed for eliminating the instability of the pulse train. (C) 2015 Optical Society of America
Efficient high-energy passively Q-switched Nd:YLF/Cr4+: YAG UV laser at 351 nm with pulsed pumping in a nearly hemispherical cavity
(2013-02-15)
Huang, Y. J.
;
Tang, C. Y.
;
Tzeng, Y. S.
;
Su, K. W.
;
Chen, Y. F.
We originally utilize a nearly hemispherical cavity to accomplish the energy scale-up for a high-repetition-rate nanosecond pulsed pumped Nd:YLF laser passively Q-switched by the Cr4+:YAG saturable absorber. This compact laser is able to efficiently generate pulse energy as large as 1.38 mJ and pulse width as short as 5 ns under a pulse repetition rate of 100 Hz. Further employing the developed Nd: YLF laser to perform extracavity harmonic generations, the maximum pulse energies of 490 mu J at 527 nm and 360 mu J at 351 nm are achieved with the shortest pulse duration of 4 ns. (C) 2013 Optical Society of America
Efficient high-power terahertz beating in a dual-wavelength synchronously mode-locked laser with dual gain media
(2014-03-15)
Huang, Y. J.
;
Tzeng, Y. S.
;
Tang, C. Y.
;
Chiang, S. Y.
;
Liang, H. C.
We originally present a novel tactic to accomplish a compact efficient dual-wavelength synchronously mode-locked laser by physically combining the Nd:YVO4 crystal to the Nd: GdVO4 crystal as a composite gain medium. With the developed method, the total output power at 1.06 mu m could be effectually produced to reach 1.3 W under the optimally balanced two-color intensities. The corresponding mode-locked pulse width and repetition rate are measured to be 47 ps and 2.86 GHz, respectively. Through the optical beating between two carrier frequencies of dual-color synchronous pulses, a train of 0.32 THz ultrashort pulses is further generated with the effective duration of down to 1.6 ps. (C) 2014 Optical Society of America
Efficient high-pulse-energy eye-safe laser generated by an intracavity Nd:YLF/KTP optical parametric oscillator: role of thermally induced polarization switching
(2012)
Huang, Y. J.
;
Tang, C. Y.
;
Huang, Y. P.
;
Cho, C. Y.
;
Su, K. W.
A high-pulse-energy eye-safe laser at 1552 nm is effectually generated by an intracavity Nd:YLF/KTP optical parametric oscillator (OPO) with the help of the thermally induced polarization switching. The polarization characteristics of the c-cut Nd:YLF laser at 1053 nm in the continuous-wave (CW) and Q-switched operation are comprehensively investigated. We experimentally verify the thermally induced birefringence can lead to a polarization switching between the mutually orthogonal components of the fundamental pulses. Consequently, an efficient intracavity nonlinear frequency conversion can be achieved in an optically isotropic laser crystal without any additional polarization control. With this finding, the pulse energy and peak power of the compact Nd: YLF/KTP eye-safe laser under an incident pump power of 12.7 W and a pulse repetition rate of 5 kHz are up to 306 mu J and 4 kW, respectively.
Efficient passively Q-switched Nd:YLF TEM00-mode laser at 1053 nm: selection of polarization with birefringence
(2012-08-01)
Huang, Y. J.
;
Tang, C. Y.
;
Lee, W. L.
;
Huang, Y. P.
;
Huang, S. C.
"The natural birefringence of the Nd:YLF crystal is utilized to achieve a reliable TEM00-mode linearly polarized laser at 1053 nm in a compact concave-plano resonator. The efficient selection of the polarization relies on the combined effect of the difference in diffraction angle for sigma- and pi-polarization of a wedged laser crystal and the alignment sensitivity of an optical resonator. We further employ a Cr4+:YAG saturable absorber to perform the passively Q-switched operation. At an incident pump power of 12 W, the maximum average output power is up to 2.3 W with a pulse repetition rate of 8 kHz and a pulse width of 9 ns. The pulse energy and peak power are found to be 288 mu J and 32 kW, respectively."
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.
;
Huang, Y. J.
;
Tang, C. Y.
;
Su, K. W.
;
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
Power scale-up of high-pulse-energy passively Q-switched Nd:YLF laser: influence of negative thermal lens enhanced by upconversion
(2012)
Huang, Y. J.
;
Tang, C. Y.
;
Huang, Y. P.
;
Huang, S. C.
;
Su, K. W.
"We develop a practical method to extend the power scale-up for a laser in a concave-plano cavity to be influenced by a large negative thermal lens. With the developed method, we successfully scale up the output power of a compact high-pulse-energy passively Q-switched Nd:YLF laser at 1053 nm with the Cr4+:YAG crystal as a saturable absorber. At an incident pump power of 12.6 W, the maximum output power under the optimum operation at 1053 nm reaches 2.61 W with a pulse width of 6 ns and a pulse repetition rate of 4.6 kHz. More importantly, we experimentally verify that the energy-transfer upconversion significantly enhances the negative focal length of thermal lens in the passively Q-switched Nd:YLF laser. (C) 2012 by Astro, Ltd."
Scaling output energy in a diode-end-pumped passively Q-switched laser with a flat-flat resonator
(2017-01)
Tang, C. Y.
;
Huang, Y. J.
;
Liang, H. C.
;
Chen, Y. F.
;
Su, K. W.
The spatial and temporal behaviors in a diode-end-pumped passively Q-switched laser with a flat-flat resonator are systematically explored as a function of the cavity length. A Nd:YAG/Cr4+:YAG miniature laser is experimentally used to show that the scale-up of the pulse energy without the higher-order transverse modes can be practically realized by optimizing the cavity length as a function of the pump size. A theoretical analysis is performed to confirm the experimental results. The extracavity second harmonic generation is experimentally conducted to demonstrate the usefulness of the laser design. PACS number(s): 42.60. Gd Q-switching; 42.55. Xi Diode-pumped lasers; 42.55.-f Lasers; 42.65.Sf Dynamics of nonlinear optical systems; optical instabilities, optical chaos and complexity, and optical spatiotemporal dynamics.
Tunable GHz pulse repetition rate operation in high-power TEM00-mode Nd:YLF lasers at 1047 nm and 1053 nm with self mode locking
(2012-07-30)
Huang, Y. J.
;
Tzeng, Y. S.
;
Tang, C. Y.
;
Huang, Y. P.
;
Chen, Y. F.
We report on a high-power diode-pumped self-mode-locked Nd:YLF laser with the pulse repetition rate up to several GHz. A novel tactic is developed to efficiently select the output polarization state for achieving the stable TEM00-mode self-mode-locked operations at 1053 nm and 1047 nm, respectively. At an incident pump power of 6.93 W and a pulse repetition rate of 2.717 GHz, output powers as high as 2.15 W and 1.35 W are generated for the sigma- and pi-polarization, respectively. We experimentally find that decreasing the separation between the gain medium and the input mirror not only brings in the pulse shortening thanks to the enhanced effect of the spatial hole burning, but also effectively introduces the effect of the spectral filtering to lead the Nd: YLF laser to be in a second harmonic mode-locked status. Consequently, pulse durations as short as 8 ps and 8.5 ps are obtained at 1053 nm and 1047 nm with a pulse repetition rate of 5.434 GHz. (C) 2012 Optical Society of America