Browsing by Author "Tsai, SW"

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A diode-pumped high power Q-switched and self-mode-locked Nd : YVO4 laser with a LiF : F-2(-) saturable absorber
(2001-08-01)
Chen, YF
;
Tsai, SW
;
Wang, SC
;
Chen, J
;
電子物理學系
Simultaneous mode-locking and Q-switching has been accomplished in a diode-pumped Nd:YVO4/LiF:F-2(-) laser. At an absorbed pump power of 23.6 W, the average output power was 6.0W and the repetition rate of the Q-switched pulse was 260 kHz. A depth of mode-locking of 100% was obtained and there was no satellite pulse between mode-locked pulse trains. The mode-locked pulse inside the Q-switched pulse had a repetition rate of approximately 148 MHz and its average duration was estimated to be around 75 ps.
Analysis of passively Q-switched lasers with simultaneous modelocking
(2002-03-01)
Chen, YF
;
Lee, JL
;
Hsieh, HD
;
Tsai, SW
;
電子物理學系
Simultaneous Q-switching and modelocking in a diode-pumped Nd: YAG/Cr4+ : YAG laser is experimentally demonstrated. A general recurrence is derived for the analysis of the temporal shape of a single Q-switched envelope with modelocked pulse trains. With the developed model, the mode-locked pulse energy and the total Q-switched pulse energy can be calculated. Excellent agreement was found between the present results and detailed theoretical computations.
Compact efficient intracavity optical parametric oscillator with a passively Q-switched Nd : YVO4/Cr4+: YAG laser in a hemispherical cavity
(2003-10-01)
Chen, YF
;
Chen, SW
;
Chen, YC
;
Lan, YP
;
Tsai, SW
A compact eye-safe optical parametric oscillator (OPO) using a noncritically phase-matched KTP crystal intracavity pumped by a passively Q-switched Nd: YVO4 laser is experimentally demonstrated. To enhance the performance of passive Q-switching, a Cr4+: YAG saturable absorber crystal is coated as an OPO output coupler in a nearly hemispherical cavity. With an incident pump power of 2.5 W, the compact intracavity OPO cavity, operating at 62.5 kHz, produces average powers at 1573 nm up to 255 mW and peak powers higher than 1 kW.
Diode-end-pumped passively mode-locked high-power Nd : YVO4 laser with a relaxed saturable Bragg reflector
(2001-02-15)
Chen, YF
;
Tsai, SW
;
Lan, YP
;
Wang, SC
;
Huang, KF
We demonstrate a high-power passively mode-locked Nd:YVO4 laser that uses a saturable Bragg reflector (SBR) with strain relaxation. 23.5 W of average power with similar to 21.5-ps cw mode-locked pulse trains was generated at a 50-W pump power. Experimental results show that appropriate strain relaxation in the SBR makes the mode-locking operation less sensitive to temperature variation. (C) 2001 Optical Society of America OCIS codes: 140.3530, 140.3580, 140.4050, 140.7090, 160.6000.
Diode-pumped Q-switched laser with intracavity sum frequency mixing in periodically poled KTP
(2004-07-01)
Chen, YF
;
Chen, YS
;
Tsai, SW
;
電子物理學系
;
光電工程學系
We report on a diode pumped Q-switched yellow-orange laser, with intracavity sum-frequency generation, in a periodically poled KTiOPO4 crystal in a diode-pumped Q-switched dual-wavelength laser at 1064 and 1342 nm. The conversion efficiency is measured as a function of crystal temperature, incident pump power, and pulse repetition rate. Under optimal phase-matching conditions, the highest yellow-orange average power was 610 mW at a pump power of 17 W.
Diode-pumped Q-switched Nd : YVO4 yellow laser with intracavity sum-frequency mixing
(2002-03-15)
Chen, YF
;
Tsai, SW
;
電子物理學系
;
光電工程學系
;
Department of Electrophysics
A compact high-power yellow pulsed laser has been. demonstrated by use of intracavity sum-frequency mixing in a diode-end-pumped Q-switched Nd:YVO4 dual-wavelength laser. A three-mirror configuration forming two separate laser cavities is used to optimize the gain match for simultaneous dual-wavelength emission in Q-switched operation. Under the optimum cavity-length condition, the highest yellow average power is 340 mW and the peak power is 2 kW, obtained at 12.5 W of pump power. (C) 2002 Optical Society of America.
Effects of 3 '-phosphoadenosine 5 '-phosphate on the activity and folding of phenol sulfotransferase
(1998-02-20)
Yang, YS
;
Tsai, SW
;
Lin, ES
;
生物科技學系
;
Department of Biological Science and Technology
Known spectroscopic and kinetic data are used to formulate pathways of the physiological and transfer reactions and the substrate inhibition of phenol sulfotransferase. Kinetic mechanisms indicate that release of PAP from enzyme complex is required for the physiological reaction but not for the transfer reaction. The pathways explain rate difference between the physiological and transfer reactions since the release of PAP is the rate-limiting step of the former reaction. Two enzyme species of phenol sulfotransferase which distinguish the physiological and transfer reaction were found to involve the binding of PAP. Differences between two forms of phenol sulfotransferase, alpha and beta, indicate that they assemble through different folding process. It is demonstrated that only alpha enzyme renatures in the presence of PAP and beta enzyme renatures only ir. the absence of PAP in vitro. In the over-expressed system, formation of alpha and beta phenol sulfotransferase is also dependent on the availability of PAP in Escherichia coli. It is concluded that folding of phenol sulfotransferase is assisted by PAP to form alpha enzyme. In the absence of PAT, beta form of phenol sulfotransferase is produced. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.
Efficient generation of continuous-wave yellow light by single-pass sum-frequency mixing of a diode-pumped Nd : YVO4 dual-wavelength laser with periodically poled lithium niobate
(2002-10-15)
Chen, YF
;
Tsai, SW
;
Wang, SC
;
Huang, YC
;
Lin, TC
We report efficient generation of cw yellow light by use of single-pass sum-frequency mixing from a diode-pumped Nd:YVO4 dual-wavelength laser with periodically poled lithium niobate. A diode-pumped Nd:YVO4 dual-wavelength laser is implemented with a three-mirror cavity, and the optimum oscillation condition is obtained from theoretical analysis. We extracted 78 mW of power at 593 run from 1.2 W at 1064 nm and from 1.0 W at 1342 nm in a beam with excellent quality. The output power could probably be increased to similar to92 mW by antireflection. coating of the crystal. (C) 2002 Optical Society of America.
High-power diode-end-pumped passively mode-locked Nd : YVO4 laser with a relaxed saturable Bragg reflector
(2002)
Tsai, SW
;
Lan, YP
;
Wang, SC
;
Huang, KF
;
Chen, YF
We present an efficient diode-end-pumped passively mode-locked Nd:YVO4 laser with a relaxed single-quantum-well saturable Bragg reflector (SBR), which average output power is more than 23 W and pulse duration 21.5 ps cw mode-locking is generated corresponding to 50 W pumping power. The overall optical-optical efficiency reaches 47% and to our knowledge, this is the highest conversion efficiency ever reported for passively mode-locked laser with average output power over 20 W. In this experiment, the broad absorption spectrum of the relaxed SBR leads a mode-locking operation to less sensitive to temperature variation. The output power corresponding to the transition from cw operation to QML and QML to CWML were also investigated. We believe the high reliability and stability of this mode-locked laser with a relaxed SBR will be interesting in laser application.
High-power diode-pumped actively Q-switched Nd : YAG laser at 1123 nm
(2004-04-15)
Chen, YF
;
Lan, YP
;
Tsai, SW
;
電子物理學系
;
光電工程學系
A high-power diode-pumped Nd:YAG laser at 1123 nm is acousto-optically Q-switched at a pulse repetition rate range of 5-20 kHz. Experimental results reveal that the resonator mirrors need to suppress parasitic oscillations on lines in the 1064 nm as well as 1319 nm regions for actively Q-switching operation. With an incident pump power of 19.2 W, the pulse energy increases from 0.15 mJ at 20 kHz to 0.4 mJ at 5 kHz. The highest peak power is up to 8.0 kW at 5 kHz. Furthermore, a conventional model of coupled rate equations is used to analyze the experimental data. The general agreement indicates that the simple model is adequate for a first order prediction of the low-gain laser characteristics. (C) 2004 Elsevier B.V. All rights reserved.
High-power diode-pumped nonlinear mirror mode-locked Nd : YVO4 laser with periodically-poled KTP
(2001-03-01)
Chen, YF
;
Tsai, SW
;
Wang, SC
;
電子物理學系
;
光電工程學系
We demonstrate a high-power nonlinear mirror (NLM) mode-locked Nd:YVO4 laser with a periodically poled KTP (PPKTP). With a 10-mm-long PPKTP crystal, 5.6 W of average power with 20-ps of pulse duration was generated at 18-W of pump power. Compared with conventional type-Il KTP crystal with the same length, the stability against the Q-switched mode-looking (QML) is significantly increased with PPKTP in NLM laser; and the pulse duration was also considerably reduced.
High-power diode-pumped Q-switched and mode-locked Nd : YVO4 laser with a Cr4+: YAG saturable absorber
(2000-10-01)
Chen, YF
;
Tsai, SW
;
Wang, SC
;
電子物理學系
;
光電工程學系
We demonstrate a high-power passively Q-switched and mode-locked Nd:YVO4 laser with a Cr4+:YAG saturable absorber. 2.7 W of average power with an 18-kHz Q-switched repetition rate was generated at a 12.5-W pump power. The peak power of a single pulse near the maximum of the Q-switched envelope was greater than 100 kW. (C) 2000 Optical Society of America.
High-repetition-rate eye-safe optical parametric oscillator intracavity pumped by a diode-pumped Q-switched Nd : YVO4 laser
(2003-03-01)
Chen, YF
;
Chen, SW
;
Tsai, SW
;
Lan, YP
;
電子物理學系
A high-repetition-rate eye-safe optical parametric oscillator (OPO), using a non-critically phase-matched KTP crystal intracavity pumped by an acousto-optically (AO) Q-switched Nd:YVO4 laser, is experimentally demonstrated. It is found that the average OPO signal power at 1573 nm can be efficiently increased by increasing the pulse repetition rate. Moreover, the intracavity OPO process effectively shortens the pulse width so that it is in the range 5 similar to 8 ns for pulse repetition rates of 10 to 80 kHz. As a result of the relatively short pulse, the peak power at 1573 nm is higher than 2 kW at a pulse repetition rate of 80 kHz.
Output optimization of a high-repetition-rate diode-pumped Q-switched intracavity optical parametric oscillator at 1.57 mu m
(2003-10-01)
Chen, YF
;
Chen, SW
;
Tsai, SW
;
Lan, YP
;
電子物理學系
The output optimization of a high-repetition-rate diode-pumped Q-switched intracavity optical parametric oscillator at 1573 nm with a type-II non-critically phase-matched x-cut KTP is experimentally and theoretically studied. The optimum output reflectivity is found to be 85%-90% for the maximum average power. The average conversion efficiency from diode-laser input power to OPO signal output power is up to 15% at a pulse repetition of 80 kHz. However, the optimum output reflectivity for the maximum peak power is found to be 60%-70%; the overall peak power amounts to 3-4 kW at a pulse repetition of 80 kHz.
Simultaneous mode locking in a diode-pumped passively Q-switched Nd : YVO4 laser with a GaAs saturable absorber
(2001-11-20)
Chen, YF
;
Huang, KF
;
Tsai, SW
;
Lan, YP
;
Wang, SC
Simultaneous mode locking and Q switching is accomplished in a diode-pumped Nd:YVO4/GaAs laser. The average output power is similar to2.0 W at 10.6-W absorbed pump power, and the repetition rate of the Q-switched pulse is similar to 120 kHz. The mode-lo eked pulse inside the Q-switched pulse has a repetition rate of similar to 148 MHz, and its average duration is estimated to be similar to 100 ps. (C) 2001 Optical Society of America.
Simultaneous Q-switching and mode-locking in a diode-pumped Nd : YVO4-Cr4+: YAG laser
(2001-04-01)
Chen, YF
;
Tsai, SW
;
電子物理學系
;
光電工程學系
;
Department of Electrophysics
Parametric studies of passive Q-switching and mode-locking in a Nd3+ :YVO4-Cr4+ :YAG laser were theoretically carried out, Simultaneous mode-locking and Q-switching was also experimentally studied. It was found that over 90% of the output power could be mode-locked in a diode-pumped passively Q-switched Nd3+:YVO4-Cr4+:YAG laser. The average pulse duration of the mode-locked pulse train was estimated to be around 110 similar to 150 ps, The highest peak power of a single pulse near the maximum of the Q-switched envelope was greater than 100 kW.