Browsing by Author "Su, Kuan-Wei"

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Comparative Study Between Extracavity and Intracavity Frequency-Doubled Laser at 532 nm: Application for the Deep Ultraviolet Generation at 266 nm
(2015-01-01)
Huang, Yu-Jen
;
Tang, Cheng-Yu
;
Cho, Chun-Yu
;
Su, Kuan-Wei
;
Chen, Yung-Fu
We construct a reliable actively Q-switched Nd:YVO4 laser to comparatively investigate the output performance of the second harmonic generation between the extracavity and intracavity configurations under a similar operated condition. It is experimentally found that the peak power at 532 nm obtained with the extracavity second harmonic generation is remarkably higher than that obtained with the intracavity configuration, even though the higher output power and larger pulse energy can be acquired with the intracavity second harmonic generation. We further perform the extracavity fourth harmonic generation to verify that the extracavity second harmonic generation is more advantageous in generating deep ultraviolet laser at 266 nm than the intracavity one, where the conversion efficiencies from 532 to 266 nm for each case are 37.1% and 7.2%, respectively. Moreover, under an incident pump power of 26 W at 808 nm and a pulse repetition rate of 40 kHz, the output power at 266 nm as high as 1.67 W is effectually generated with the combination of the extracavity second and fourth harmonic generations, corresponding to the conversion efficiency from 808 to 266 nm up to 6.4%.
Efficient Continuous-Wave Self-Raman Nd:KGW Laser With Intracavity Cascade Emission Based on Shift of 89 cm(-1)
(2015-01-01)
Tang, Cheng-Yu
;
Zhuang, Wei-Zhe
;
Su, Kuan-Wei
;
Chen, Yung-Fu
;
電子物理學系
We demonstrated a continuous-wave (CW) self-Raman laser with high conversion efficiency by using Nd:KGW as the Raman crystal based on the Raman shift of 89 cm(-1). The maximum Raman output power was as high as 0.42 W under the pump power of 2.5 W. The diode-to-Stokes optical conversion efficiency was found to be 16.8% which is outstanding among Nd-doped CW self-Raman lasers. Besides, three resonators have been investigated to generate CW self-Raman lasers with different Raman shift of the Nd: KGW crystal at 1077.9 nm (89 cm(-1)), 1162.9 nm (768 cm(-1)), 1181.2 nm (901 cm(-1)), and 1193.7 nm (89cm(-1) + 901cm(-1)). These Raman lasers pave the way to generate more-closely spaced set of CW emission in the green-yellow-orange region.
Efficient Diode-Pumped Solid-State Laser At 266 nm
(2013)
Tang, Cheng-Yu
;
Huang, Yu-Jen
;
Su, Kuan-Wei
;
Chen, Yung-Fu
;
電子物理學系
We construct a reliable actively Q-switched Nd:YVO4 laser to make a comparative study for the second harmonic generation between the extracavity and intracavity configurations under a similar operated condition. The output power at 266 nm as high as 1.67 W is effectually generated with the combination of the extracavity second and fourth harmonic generations under an incident pump power of 26 W at 808 nm and a pulse repetition rate of 40 kHz, corresponding to the conversion efficiency from 808 to 266 nm up to 6.4 %.
Efficient High-Energy Pulsed Pumped Passively Q-switched Nd:YLF/Cr4+:YAG UV Laser At 351 nm with a Nearly Hemispherical Cavity
(2013)
Huang, Yu-Jen
;
Tang, Cheng-Yu
;
Su, Kuan-Wei
;
Chen, Yung-Fu
;
電子物理學系
We utilize a nearly hemispherical cavity to develop a pulsed pumped passively Q-switched Nd:YLF/Cr4+:YAG UV laser. The pulse energy and peak power at 351 nm are efficiently generated to be 360 mu J and 44.1 kW.
Efficient high-peak-power diode-pumped actively Q-switched Nd:YAG/YVO(4) intracavity Raman laser
(2008-12-10)
Su, Kuan-Wei
;
Chang, Ya-Ting
;
Chen, Yung-Fu
;
電子物理學系
;
Department of Electrophysics
An undoped YVO(4) crystal is employed to achieve efficient stimulated Raman scattering conversion in a diode-pumped actively Q-switched Nd:YAG laser. With an incident pump power of 16.2 W, an 1176 nm first Stokes average output power of 3.0 W was generated at a pulse repetition rate of 50 kHz, corresponding to an optical-to-optical conversion efficiency of 18.3%. Moreover, the maximum optical-to-optical conversion efficiency of 21.3% was found at 20 kHz. The maximum pulse energy is higher than 83 mu J at both 20 and 30 kHz. With an incident pump power of 7.6W, the underestimated peak power of 43.5 kW was demonstrated at 20 kHz with mode-locked modulation. (c) 2008 Optical Society of America
Efficient high-peak-power diode-pumped actively Q-switched Nd:YAG/YVO4 intracavity Raman laser
(2008-12-10)
Su, Kuan-Wei
;
Chang, Ya-Ting
;
Chen, Yung-Fu
;
電子物理學系
;
Department of Electrophysics
An undoped YVO4 crystal is employed to achieve efficient stimulated Raman scattering conversion in a diode-pumped actively Q-switched Nd:YAG laser. With an incident pump power of 16.2 W, an 1176 nm first Stokes average output power of 3.0 W was generated at a pulse repetition rate of 50 kHz, corresponding to an optical-to-optical conversion efficiency of 18.3%. Moreover, the maximum optical-to-optical conversion efficiency of 21.3% was found at 20 kHz. The maximum pulse energy is higher than 83 mu J at both 20 and 30 kHz. With an incident pump power of 7.6W, the underestimated peak power of 43.5 kW was demonstrated at 20 kHz with mode-locked modulation. (c) 2008 Optical Society of America
Exploring the Emergence of the Self-Q-Switching in Diode-Pumped Yb:KGW Monolithic Lasers
(2018-09-01)
Huang, Tzu-Lin
;
Liang, Hsin-Chih
;
Su, Kuan-Wei
;
Chen, Yung-Fu
;
電子物理學系
We perform through experiments to explore the key factors for the emergence of a self-Q-switching phenomenon in diode-pumped Yb: KGW lasers. In addition to the output transmission, it is found that the mode-to-pump size ratio is a critical factor leading to the self-Q-switching. The region of the cavity mode volume without overlapping the pump volume plays a role of modulation loss to result in self-Q-switching. With an output transmission of 4% and a mode-to-pump size ratio of approximately 1.2, simultaneous self-Q-switching and self-mode-locking with the repetition rate of 23.1 GHz were experimentally observed. At an incident pump power of 9.2 W, the maximum pulse energy was estimated to be 1.4 mu J at the repetition rate of 880 kHz with an average output of 1.27 W.
Exploring the spatio-temporal dynamics of an optically pumped semiconductor laser with intracavity second harmonic generation
(2012-11-15)
Liang, Hsing-Chih
;
Lee, Yi-Chun
;
Tung, Jung-Chen
;
Su, Kuan-Wei
;
Huang, Kai-Feng
We experimentally observe an intriguing phenomenon of complex spatio-temporal dynamics in a commercial optically pumped semiconductor laser with intracavity second harmonic generation. We numerically verify that the experimental results come from the total mode locking of transverse electromagnetic modes (TEM00) and higher-order modes with significant astigmatism. The scenarios of the spatio-temporal dynamics are quite similar to the phenomena in soft-aperture Kerr-lens mode locked Ti:sapphire lasers. (C) 2012 Optical Society of America
Extracting photon periodic orbits from spontaneous emission spectra in laterally confined vertically emitted cavities
(2010-08-15)
Chen, Yung-Fu
;
Yu, Yan-Ting
;
Huang, Yu-Jen
;
Chiang, Po-Yi
;
Su, Kuan-Wei
We report our observation of the signature of photon periodic orbits in the spontaneous emission spectra of large-aperture vertical-cavity surface-emitting lasers (VCSELs). The high-resolution measurement clearly demonstrates that over a thousand cavity modes with a narrow linewidth can be perfectly exhibited in the spontaneous emission spectrum just below the lasing threshold. The Fourier-transformed spectrum is analyzed to confirm that the spontaneous emission spectra of large-aperture VCSELs can be exploited to analogously investigate the energy spectra of the 2D quantum billiards. (C) 2010 Optical Society of America
Generation of High-Energy Geometric Structured Beams by Off-Axis Pumped Nd:YAG/Cr4+:YAG Lasers with Degenerate Resonators
(2018-01-01)
Tuan, Pi-Hui
;
Hsieh, Yen-Hui
;
Liang, Hsin-Chih
;
Su, Kuan-Wei
;
Chen, Yung-Fu
Off-axis pumped Nd:YAG/Cr4+:YAG lasers under degenerate cavity conditions are explored to achieve high-pulse-energy geometric modes for beam transformation. The employment of Nd:YAG crystal promises efficient passively Q-switched (PQS) operation with a flexible cavity length to ensure various PQS geometric modes with stable structures can be generated. It is experimentally confirmed that the output energy and peak power of the PQS geometric modes can easily reach up to over 100 mu J and 10 kW with fairly stable pulse trains in pure linear polarization. Various high-energy vortex beams carrying large angular momentum and diverse phase structures are achieved by converting the planar geometric modes into the circular ones to offer promising light sources for potential applications.
Influence of High-Order Modes in Starting Self-Mode-Locked Optically Pumped Semiconductor Laser
(2013)
Liang, Hsing-Chih
;
Lee, Yi-Chun
;
Tung, Jung-Chen
;
Su, Kuan-Wei
;
Chen, Yung-Fu
We explored the influence of pump-to-mode size ratios on optically pumped semiconductor laser. With a large pump-to-mode size ratio, the output beam was self-modelocked with 1.17 ps pulse duration at a repetition rate of 1.8GHz.
Investigation on Polarization Features of Broad-Area Square-Shaped VCSELs with Different Frequency Detuning: High-Order Modes Assisted in Stable Polarization Emission
(2013)
Yu, Yan-Ting
;
Tuan, Pi-Hui
;
Su, Kuan-Wei
;
Chen, Yung-Fu
;
電子物理學系
We experimentally confirm frequency detuning is the crucial factor for being capable of polarization switching in broad-area square-shaped VCSELs. Intriguingly, the VCSEL can exhibit stable polarization in light output for relatively large frequency detuning.
Nondiffracting Superlattice Beams
(2013)
Tsou, Chia-Han
;
Wu, Tai-Wei
;
Tung, Jung-Chen
;
Liang, Hsing-Chih
;
Su, Kuan-Wei
We introduce a class of optical superlattices that are formed by two sets of wave vectors with single wave number but different azimuths. By a collimated light to illuminate a mask with multiple apertures, we generate nondiffracting superlattice beams.
Power Scaling in a Diode-End-Pumped Multisegmented Nd:YVO4 Laser With Double-Pass Power Amplification
(2015-01-01)
Huang, Yu-Jen
;
Zhuang, Wei-Zhe
;
Su, Kuan-Wei
;
Chen, Yung-Fu
;
交大名義發表
We demonstrate a high-power master oscillator power amplifier with the double-pass configuration based on the specially designed multisegmented Nd:YVO4 crystals. A powerful mathematical technique on the basis of the Fourier eigenfunction expansion method is developed for precisely calculating the temperature distribution inside the gain medium. A seed Nd:YVO4 oscillator under dual-end pumping is subsequently constructed for efficiently emitting the output power of up to 50 W. Moreover, under a total incident pump power of 244 W at 808 nm, as high as 108 W of the output power at 1064 nm is further generated in our developed master oscillator power amplifier system. Theoretical and experimental results clearly reveal that the gain medium with multiple doping concentrations is practically valuable for constructing a high-power end-pumped laser without bringing in significantly thermal effects.
The influence of UV filter and Al/Ag moisture barrier layer on the outdoor stability of polymer solar cells
(2020-03-15)
Weng, Chia-Ning
;
Yang, Hao-Chun
;
Tsai, Cheng-Yu
;
Chen, Szu-Han
;
Chen, Yan-Syun
The degradation of the polymer solar cells in the outdoor condition was studied. It was found that the devices with normal structure (ITO/PEDOT:PSS/PBDTTT-EFT:PC71BM/ZrOx/Al) show better stability than those with inverted device structure (ITO/ZnO/PBDTTT-EFT:PC71BM/MoO3/Ag). PBDTTT-EFT is poly[4, 8-bis(5-(2-ethylhexyl) thiophen-2-yl) benzo [1,2-b;4,5-b] dithiophene-2, 6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno [3,4-b] thiophene-) - 2-carboxylate-2-6-diyl)] and PC71BM is [6,6]-phenyl-C71-butyric acid methyl ester. The major cause of degradation was attributed to the ultraviolet (UV) part of the sunlight. When the UV filter with cut-off wavelength of 400 nm was used to protect the device, the decay rate was improved by 50 times and the protected device retains 95% of their initial power conversion efficiency after 13 days outside. In the meanwhile, the decay of device fabricated by toluene was found 8 times faster than device by chlorobenzene. Thin 20 nm of Ag capping layer can further improve the stability. Degradation under water immersion indicates that the major effect of Ag is to protect against the residual moisture inside the encapsulation.
The Influences of Boundary Shapes on Polarization Characteristics and Lasing Modes in Broad-Area Vertical-Cavity Surface-Emitting Lasers With Cryogenic Detuning: Regular Versus Chaotic Cavities
(2015-11-01)
Yu, Yan-Ting
;
Tuan, Pi-Hui
;
Chiang, Po-Yi
;
Su, Kuan-Wei
;
Huang, Kai-Feng
The broad-area rectangular-shaped and stadiumshaped VCSELs with nearly the same aspect ratio are designed to explore the influence of lateral boundary shapes on polarization states and lasing spectra with large detuning by cryogenic cooling. For the rectangular-shaped VCSEL, the lasing modes usually exhibit linearly polarized state and their far-field emissions mainly concentrate on four diagonal directions. On the other hand, the lasing modes of the stadium-shaped VCSEL generally display two orthogonally polarized states and their far-field emissions extensively spread on azimuthal directions. More intriguingly, the lasing spectra of the two devices clearly manifest the features of the energy-level distribution in regular and chaotic quantum billiards, respectively.