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1.
Parametric studies of passive Q-switching and mode-locking in a Nd 3+: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 he around 110~150 ps. The highest peak power of a single pulse near the maximum of the Q-switched envelope was greater than 100 kW 相似文献
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We demonstrate the performance of a Nd:YAG laser, passively Q-switched with a Cr4+:YAG plate, which plays the double role of a passive Q-switch and a Brewster plate. The Brewster plate configuration contributes an intracavity loss of approximately 3.2-10 -3 cm-1 along the cavity length. Losses contributed by the active Cr4+ ions in the plate relate to their excited state absorption. A freshly measured transmission saturation curve of Cr4+:YAG suggests a ground state absorption cross section σgs=(8.7±0.8)-10-19 cm2, and an excited state absorption cross section σes=(2.2±0.2)-10-19 cm2 of the Cr4+ ions at λ=1064 nm 相似文献
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A general and straightforward model was developed for the design of passively Q-switched lasers. With the second-threshold criterion and using a numerically fitting procedure, the output pulse energy was expressed as an analytical function of the initial transmission of the saturable absorber and the reflectivity of the output coupler. An analytical expression for the optimal output reflectivity was also obtained for maximizing the output pulse energy of a passively Q-switched laser with a given initial transmission of the saturable absorber. Excellent agreement was studied between the present results and detailed theoretical computations. A Nd:YAG laser with Cr4+ :YAG as a saturable absorber has illustrated the use of the present model 相似文献
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Tunable Cr4+:YSO Q-switched Cr:LiCAF laser 总被引:1,自引:0,他引:1
Tunable passive Q-switching (781 nm to 806 nm at 300 K) of a flash-lamp pumped Cr3+:LiCaAlF6 (Cr:LiCAF) laser with a Cr4+:Y2SiO5 (Cr4+:YSO) broad-band solid-state saturable absorber has been realized. Typical pulse widths of the Q-switched laser output ranged from 40 ns to 80 ns, depending on the lasing wavelength. Spectral narrowing and reduced beam diameter with the use of the saturable absorber were observed. The ground state and the excited state absorption cross sections of the Cr4+:YSO absorber were found by bleaching experiments to be (7.0±1.4)×10-19 cm2 and (2.3±0.5)×10-19 cm2 at 694 nm, respectively. Numerical simulation was utilized to simulate the Cr:LiCAF passive Q-switching with Cr4+ :YSO solid-state saturable absorber 相似文献
5.
Xingyu Zhang Shengzhi Zhao Qingpu Wang Qidi Zhang Lianke Sun Shaojun Zhang 《Quantum Electronics, IEEE Journal of》1997,33(12):2286-2294
Cr4+-doped saturable absorbers are characterized by long excited state lifetime and appreciable excited state absorption. In the paper, we first solve the three coupled rate equations describing the operation of Cr4+-doped saturable-absorber passively Q-switched lasers to obtain the expressions of pulse characteristics such as output energy, peak power, and pulsewidth. We then determine the key parameters of an optimally coupled passively Q-switched laser as functions of two variables concerning the amplifying medium, saturable-absorber medium, and pump level, and generate several design curves. These key parameters include the optimal normalized coupling parameter and the optimal normalized saturable-absorber parameter which maximize the output energy (or maximize the peak power, or minimize the pulsewidth), and the corresponding normalized energy, normalized peak power, and normalized pulsewidth. The results are valid for not only Cr 4+-doped saturable-absorber Q-switched lasers but also any other lasers passively Q-switched by saturable absorbers with long excited state lifetime and appreciable excited state absorption. Using the expressions and design curves, with the aid of a simple hand calculator, one can predict the pulse characteristics and perform the design of an optimally coupled passively Q-switched laser 相似文献
6.
Self-Q-switched operation of Nd3+: YAG lasers at 77°K and ruby lasers at 300 and 77°K pumped by the 5145-Å output of a pulsed argon ion laser is described. Self-Q-switched operation was obtained 1) by static mirror misalignment and 2) by static misalignment of the filament of the pumped laser material with respect to the mirror resonator axis. An output that consisted of a single giant pulse could be obtained for ruby by either method; for Nd3+: YAG, the output always consisted of one or more giant pulses and characteristic relaxation oscillations. 相似文献
7.
A high-power and high-repetition-rate passively Q -switched ytterbium-doped single-mode double-clad fiber laser was built using a Cr4+:YAG saturable absorber (SA). Two different SAs with initial transmissions of Tomicron = 30% and Tomicron = 50% were studied. At the maximum coupled pump power of 9.8 W, an output power of 4.7 W, pulse duration of 143 ns, pulse repetition rate of 253 KHz, pulse energy of 18.5 muJ, and slope efficiency of 49% were obtained with the Tomicron = 30% SA. 相似文献
8.
Dong J. Shirakawa A. Takaichi K. Ueda K. Yagi H. Yanagitani T. Kaminskii A.A. 《Electronics letters》2006,42(20):1154-1155
A laser-diode-pumped all-ceramic passively Q-switched Yb:YAG microchip laser with Cr4+:YAG as a saturable absorber has been demonstrated for the first time. A pulse width of 380 ps and a peak power of over 82 kW at a repetition rate of 12.4 kHz was obtained. A slope efficiency of 37% and an optical-to-optical efficiency of 30% was achieved 相似文献
9.
Modeling pulse shape of Q-switched lasers 总被引:1,自引:0,他引:1
Jingang Liu Deyuan Shen Siu-Chung Tam Yee-Loy Lam 《Quantum Electronics, IEEE Journal of》2001,37(7):888-896
A general approach describing the pulse shape and temporal width of Q-switched lasers has been derived. Based on a normalized intermediate variable describing the ratio of population inversion density at the beginning of Q-switch to that at threshold, a generalized characteristic equation that governs passively and actively Q-switched lasers is derived. From the characteristic equation, the pulse symmetry property and pulse width can be described and easily calculated for any given operating parameters, and the waveform of the laser pulse can be reconstructed without solving the laser rate equations. An approach is also given for the case of intracavity frequency-doubled Q-switched lasers. Theoretical results show agreement with experiments for a diode pumped Nd:YAG laser system that is passively Q-switched by a Cr4+ :YAG absorber 相似文献
10.
We demonstrate a Nd:YAG loop resonator with a self-pumped phase conjugate, mirror in a Cr4+:YAG crystal, in the nanosecond regime. A maximum extraction of 29 mJ and a maximum reflectivity of 3.3 are obtained. The output beam is a high-quality diffraction-limited TEM 00 mode and has a pulse shape of ~20-ns duration, showing the self Q-switching ability of the resonator. In addition, we demonstrate an original and specific configuration of the anisotropic Cr4+:YAG crystal that compensates not only for phase aberrations but also for polarization aberrations induced into the loop resonator 相似文献
11.
Azkargorta J. Iparraguirre I. Balda R. Fernandez J. 《Quantum Electronics, IEEE Journal of》1997,33(3):474-482
Energy transfer between Cr3+ and Nd3+ ions has been investigated in the 4.2-300-K temperature range by using steady-state and site-selective time-resolved laser spectroscopy. Radiative and nonradiative energy transfer has been studied from the time-resolved emission spectra and the donor fluorescence decays. The transfer efficiency was calculated as a function of temperature by using the Cr3+ lifetimes of the single doped and co-doped samples. Laser experiments were carried out in a diffusive cavity by pumping a co-doped rod 54 mm long and 5 mm in diameter with xenon flashlamps. The laser spectral emission shows a complex structure which varies as a function of pump energy. The temporal evolution of the laser spectrum is discussed in terms of a simple four-level spectral rate-equation laser model which takes into account the existence of two main broad Nd3+ site distributions with a large spectral overlap 相似文献
12.
激光二极管泵浦的Cr4+:YAG被动调Q微片激光器因其高重复频率、短脉宽、高峰值功率等优点,在光通信、激光雷达、遥感监测、非线性频率变换、激光微加工等领域有着重要应用,然而目前Cr4+:YAG被动调Q激光器脉冲输出稳定性较差,而且重复频率调谐范围窄,限制了其在气溶胶的荧光分析、测距以及空间光通信等领域中的广泛应用。实验中采用预泵浦方式,在激光二极管泵浦的Cr4+:YAG被动调Q微片激光器中获得重复频率连续可调、稳定振荡的激光脉冲输出,重复频率连续可调谐范围为2 ~28 kHz,其单脉冲能量的不稳定性优于2.50%。其中,在重复频率为20 kHz时,获得脉冲宽度为2.431 ns,单脉冲能量17.6 J,消光比252:1的脉冲输出,其幅度不稳定度约为4.00%,重复频率不稳定度约为2.40%。此类宽频可调、稳定振荡的激光二极管泵浦的Cr4+:YAG被动调Q微片激光器有着广阔的应用前景。 相似文献
13.
Performance of a Cr:YAG laser 总被引:13,自引:0,他引:13
Eilers H. Dennis W.M. Yen W.M. Kuck S. Peterman K. Huber G. Jia W. 《Quantum Electronics, IEEE Journal of》1993,29(9):2508-2512
We report on the performance of a Cr4+:YAG laser, tunable over the range from 1.32 to 1.53 μm, under different operating conditions. Laser action has been achieved by pumping with a Nd:YAG laser in the Q-switched mode and cw mode and with a Cr:Nd:GSGG laser in the long pulse mode. Slope efficiencies up to 22% in the Q-switched mode have been achieved. The lowest threshold was 30 mJ for the long pulse pumped mode. Excited state absorption seems to limit the tuning range and the output characteristics 相似文献
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Heiko Ridderbusch Thomas Graf 《Quantum Electronics, IEEE Journal of》2007,43(2):168-173
To investigate the physical mechanism of the saturation process in Cr4+:YAG crystals we solved the three coupled rate equations which describe the saturable absorber. We experimentally verified this model using two lasers with nanosecond pulses and continuous-wave radiation. We used crystalline and ceramic Cr4+-doped YAG saturable absorbers with various initial transmissions. The ratio between the ground and the excited-state absorption cross section at 1064 nm was measured to be between 3.8 plusmn 0.2 and 4.7 plusmn 0.2 for crystalline and 3.6 plusmn 0.1 for ceramic Cr4+:YAG. The ratio between the above named cross sections at 1047 nm was found to be 6.2 plusmn 0.2 for both crystalline and ceramic Cr4+:YAG. With these results the ground-state and the excited-state absorption cross sections at 1047 nm were calculated to be (9.55plusmn0.01)times10-19 cm2 and (1.54plusmn0.03)times10-19 cm2, respectively 相似文献
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Conlon P.J. Tong Y.P. French P.M.W. Taylor J.R. Shestakov A.V. 《Electronics letters》1994,30(9):709-710
Sub-100 fs pulse generation from a Kerr lens modelocked Cr4+ :YAG laser has been demonstrated for the first time, yielding femtosecond pulses tunable from 1.49 to 1.56 μm with pulses as short as 90 fs obtained at 1.53 μm 相似文献