Browsing by Author "Tzeng, Y. S."

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Effect of spatial hole burning on a dual-wavelength mode-locked laser based on compactly combined dual gain media
(2014-12-01)
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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電子物理學系
The effect of spatial hole burning (SHB) on dual-wavelength self-mode-locked lasers based on physically combined Nd:YVO4/Nd:LuVO4 and Nd:YVO4/Nd:KGW composite active medium is comparatively investigated. The length of the first Nd:YVO4 crystal is optimized to realize a highly compact and efficient TEM00-mode pico-second laser at 1.06 mu m with optical conversion efficiency greater than 20%. When the SHB effect is enhanced by decreasing the separation between the input end mirror and the composite gain medium, it is experimentally found that not only the pulse duration monotonically decreases, but also the temporal behavior gradually displays a narrow-peak-on-a-pedestal shape for the Nd:YVO4/Nd:LuVO4 scheme, while the multipulse operation can be obtained for the Nd:YVO4/Nd: KGW configuration. These phenomena are further explored by numerically simulating mode-locked pulses from the experimentally measured optical spectra. (C) 2014 Chinese Laser Press
Efficient dual-wavelength diode-end-pumped laser with a diffusion-bonded Nd:YVO4/Nd:GdVO4 crystal
(2015-10-01)
Huang, Y. J.
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Cho, H. H.
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Tzeng, Y. S.
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Liang, H. C.
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Su, K. W.
A new type of diffusion-bonded Nd:YVO4/Nd:GdVO4 hetero-composite crystal is originally designed and applied to diode-end-pumped laser for achieving an efficient dual-comb picosecond operation with self-mode locking for the first time. As high as 1.1 W of the total average output power at 1063.18 and 1064.37 nm is generated under an incident pump power of 5.1 W. The corresponding mode-locked pulse width is 42 ps at a pulse repetition rate of 3.82 GHz. Through the optical beating between two carrier frequencies of each spectral component, a train of ultrashort pulses with sub-terahertz repetition rate is further generated with the effective duration of down to 1.6 ps. (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.
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Tang, C. Y.
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Tzeng, Y. S.
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Su, K. W.
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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.
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Tzeng, Y. S.
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Tang, C. Y.
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Chiang, S. Y.
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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
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.
Generation of optical crystals and quasicrystal beams: Kaleidoscopic patterns and phase singularity
(2011-05-10)
Chen, Y. F.
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Liang, H. C.
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Lin, Y. C.
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Tzeng, Y. S.
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Su, K. W.
We explore the feasibility of the generation of pseudonondiffracting optical beams related to crystal and quasicrystal structures. It is experimentally confirmed that optical crystal and quasicrystal beams can be remarkably generated with a collimated light to illuminate a high-precision mask with multiple apertures regularly distributed on a ring. We also found that exotic kaleidoscopic patterns can be exhibited with the high-order quasicrystal beams. More importantly, the structures of phase singularities in optical quasicrystal beams are manifested.
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
NCTUns 4.0: An integrated simulation platform for vehicular traffic, communication, and network researches
(2007)
Wang, S. Y.
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Chou, C. L.
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Chin, Y. H.
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Tzeng, Y. S.
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Hsu, M. S.
In this paper, we present an integrated simulation platform, called NCTUns, for vehicular traffic, communication, and network researches. This platform combines the capabilities supported by a network simulator and those supported by a traffic simulator. With these simulation capabilities, NCTUns can be used to design protocols for Intelligent Transportation Systems (ITS) communication networks such as a wireless vehicular communication network. Besides, the novel architecture of the platform enables the real-world Linux protocol stack and any real-world application to be used in simulations of such networks. In this paper, we present the design of NCTUns for supporting ITS researches and show its scalability.
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.
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Tzeng, Y. S.
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Tang, C. Y.
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Huang, Y. P.
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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