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1.
By considering the Gaussian spatial distributions of the intracavity photon density and the initial population-inversion density, the coupled rate equations for a diode-pumped passively Q-switched and mode-locked (QML) laser with Cr4+:YAG saturable absorber are given. These coupled rate equations are solved numerically and the key parameters of an optimally coupled passively QML laser are determined for the first time. These key parameters include the parameters of the gain medium, the saturable absorber and the resonator, which can maximize the pulse energy of singly Q-switched envelope. The optimal calculations for a diode-pumped passively QML Nd:GdVO4 laser with Cr4+:YAG saturable absorber are presented to demonstrate the numerical simulation applicable.  相似文献   

2.
A diode-pumped doubly passively Q-switched intracavity-frequency-doubling Nd:LuVO4/KTP green laser with Cr4+:YAG and GaAs saturable absorbers is demonstrated. This laser can generate the shorter pulse width with higher peak power compared with the singly passively Q-switched green laser with Cr4+:YAG or GaAs saturable absorber. The relations between the pulse symmetry and the ratio of the small-signal transmissions of two saturable absorbers are investigated. By reasonably choosing the small-signal transmissions of both saturable absorbers, the doubly passively Q-switched green laser can generate the much more symmetric pulse profile. The coupled rate equations are used to simulate the passively Q-switched process of the green laser by considering the Gaussian transversal and longitudinal distributions of the intracavity photon density. The numerical results of the equations are consistent with the experimental results.  相似文献   

3.
By using both V3+:YAG and Co:LMA saturable absorbers, an xenon-lamp-pumped doubly passively Q-switched and mode-locked (QML) Nd:YAG laser at 1.3 μm in a straight cavity is realized for the first time. The modulation depth of QML pulse has nearly reached 100%. The experimental results shows that the doubly passively Q-switched and mode-locked (QML) laser can generate shorter Q-switch envelope pulse with higher average peak power in comparison to the singly passively QML laser with V3+:YAG or Co:LMA saturable absorber.  相似文献   

4.
We report on a diode-pumped passively mode-locked Nd:Gd0.64Y0.36VO4 laser with a Cr4+:YAG saturable absorber. Q-switched mode locking (QML) with 90% modulation depth was obtained. The peak power of the mode-locked pulse near the maximum of the Q-switched envelope was estimated to be about 1.7 MW at the pump power of 12 W. Besides QML, continuous-wave mode locking was also experimentally realized, for the first time to our knowledge, in the laser under a strong intracavity pulse energy fluence. The mode-locked pulse width is about 2.96 ps at a repetition rate of 161.3 MHz.  相似文献   

5.
We present a simple technique to improve the symmetry of pulse emitted by doubly passively Q-switched lasers. Using both Cr4+:YAG and GaAs saturable absorbers in the same cavity, a diode-pumped doubly passively Q-switched Nd:YVO4 laser is realized for the fist time. This laser can generate more symmetric pulse with shorter pulse width and higher peak power compared with the solely passively Q-switched laser with Cr4+:YAG saturable absorber or GaAs coupler. The pulse symmetry factor ε of such a doubly passively Q-switched laser is experimentally shown to reach 1.05. Simulations by a rate-equation model for doubly passively Q-switched laser are in close agreement with the experimental results.PACS 42.55.Xi; 42.55.Rz; 42.60.Gd  相似文献   

6.
A compact diode-pumped passively Q-switched intracavity frequency-doubled Nd:GdVO4/KTP green-pulse laser was demonstrated, using Cr4+:YAG as a saturable absorber in a simple flat–flat cavity. With a 5.9 W incident pump power, a passively Q-switched green laser was obtained with an average power of 397 mW, repetition rate of 40 kHz, and pulse width of 40 ns, when the initial transmission of Cr4+:YAG was 85%. The shortest pulse width of 30 ns, the highest green peak power of 696 W and the maximum pulse energy of 21 μJ were obtained when the initial transmission of Cr4+:YAG was 70%. Under CW green operation, we obtained 440 mW output power.  相似文献   

7.
By considering the influence of the acousto-optic (AO) modulator and the nonlinear loss due to harmonic conversion in the intra-cavity frequency-doubling laser, a developed rate equation model for diode-pumped dual-loss-modulated Q-switched and mode-locked (QML) Nd:LuVO4/KTP green laser with acousto-optic (AO) modulator and Cr4+:YAG saturable absorber is presented. With this developed model, the pulse width, single-pulse energy and the other dual-loss-modulated QML green laser characteristics are numerically simulated. The simulation results show that the turnoff time is of great importance for the pulse energy and pulse width of the Q-switched pulse. A diode-pumped dual-loss-modulated QML Nd:LuVO4/KTP laser is constructed to successfully demonstrate the numerical simulation application.  相似文献   

8.
A high power diode-end-pumped passively Q-switched and mode-locking (QML) Nd:GdVO4 laser at 912 nm was demonstrated for the first time, to the best of our knowledge. A Z-type laser cavity with Cr4+:YAG crystals as the intracavity saturable absorber were employed in the experiments. Influence of the initial transmission (TU) of the saturable absorber on the QML laser performance was investigated. Using the TU = 95% Cr4+:YAG, as much as an average output power of 2.0 W pulsed 912 nm laser was produced at an absorbed pump power of 25.0 W, then the repetition rates of the Q-switched envelope and the mode-locking pulse were ~ 224 kHz and ~ 160 MHz, respectively. Whereas the maximum output power was reduced to 1.3 W using the TU = 90% Cr4+:YAG, we obtained a 100% modulation depth for the mode-locking pulses inside the Q-switched envelope.  相似文献   

9.
J. Liang  S. Zhao  Z. Zhuo  T. Li  J. Zhao  M. Li  J. An  W. Wang  G. Du 《Laser Physics》2009,19(3):381-383
In the experiment, we have demonstrated the performance of a laser-diode, end-pumped, doubly Q-switched YVO4/Nd:YVO4 laser with both a BBO electric-optic (EO) Q-switch and Cr4+:YAG saturable absorber. At a maximum incident pump power of 15 W and an EO Q-switch repetition rate of 8 kHz, the stable laser pulses with the pulse duration 5.28 ns, the single pulse energy 0.14 mJ, and the pulse peak power 26 kW are obtained. The experimental results show that the double Q-switched laser with EO and Cr4+:YAG can generate the shorter pulse and the higher peak power in comparison to singly Q-switched laser with EO.  相似文献   

10.
We report a high repetition rate Q-switched Nd:YVO4/Cr4+:YAG micro laser with small pump power. Unwanted defects in pulse train, which are inherently large in passively Q-switched laser, was simply minimized by controlling temperature of Nd:YVO4/Cr4+:YAG medium. When T 0 = 90% Cr4+:YAG and R OC = 90% output coupler were used, Q-switched Nd:YVO4/Cr4+:YAG micro laser showed the optimum output; maximum output power of 58 mW, optical-to-optical efficiency of 9.1%, repetition rate of 1.1 MHz, and pulse width of 57 ns were achieved with 640 mW pumping. MHz-order repetition rate in Nd:YVO4/Cr4+:YAG Q-switched laser with low pumping (<1 W) is the highest value to the best of our knowledge.  相似文献   

11.
A diode pumped Nd:Y0.5Lu0.5VO4 pulse laser modulated with an acousto-optic (AO) Q-switcher and Cr4+:YAG saturable absorber is first demonstrated in this paper. The laser is shown to generate shorter pulse width than AO Q-switched laser alone, and have a higher peak power and single pulse energy than passively Q-switched laser with only Cr4+:YAG. A laser pulse width of 6.16 ns and a peak power of about 43.83 kW are achieved at the incident pumping power of 14.09 W.  相似文献   

12.
The laser characteristics of laser-diode end-pumped Yb:YAG/Cr4+:YAG composite ceramics microchip passively Q-switched lasers were studied by solving the coupled rate equations numerically taking into account the reabsorption of Yb:YAG ceramics at laser wavelength. Effects of the reflectivity of the output coupler, the concentrations and thickness of the saturable absorbers, and pump beam area on the laser performance were investigated analytically. The simulation results of the Yb:YAG/Cr4+:YAG composite ceramics passively Q-switched microchip lasers were in good agreement with the experimental data. Better laser performance (high peak power, short pulse width and good optical-to-optical efficiency) of the composite Yb:YAG/Cr4+:YAG ceramics passively Q-switched laser can be obtained by using a thin Cr4+:YAG ceramic with high concentration, suitable reflectivity of the output coupler and proper pump beam diameter under high pump power intensity according to our simulations.  相似文献   

13.
By using both acousto-optic (AO) modulator and GaAs saturable absorber, a diode-pumped doubly Q-switched and mode-locked (QML) YVO4/Nd:YVO4 laser is presented. The average output power and the pulse width of the Q-switched envelope have been measured. The Q-switch pulse energy of the doubly QML laser are higher than that only with GaAs. The stability of the QML laser with the dual-loss-modulation is significantly improved if compared to that only with GaAs.The experimental results show that the doubly QML YVO4/Nd:YVO4 laser has nearly 80% modulation depth and deeper than that of the singly passively QML pulse. The doubly Q-switched mode-locked pulse inside the Q-switched envelope has a repetition rate of 111 MHz and its pulse width is estimated to be about 700 ps. By using a hyperbolic secant square function and considering the Gaussian distribution of the intracavity photon density, the coupled equations for diode-pumped dual-loss-modulated QML laser is given and the numerical solutions of the equations are in good agreement with the experimental results.  相似文献   

14.
By considering the Gaussian spatial distributions of the intracavity photon density and the initial population-inversion density, the coupled rate equations for a diode-pumped passively Q-switched laser with V3+:YAG saturable absorber are given. These coupled rate equations are solved numerically and the key parameters of an optimally coupled passively Q-switched laser with V3+:YAG at 1342 nm are determined. These key parameters include the parameters of the gain medium, the saturable absorber and the resonator, which can maximize the pulse energy of singly Q-switched pulse. The optimal calculations for a diode-pumped passively Q-switched a-Nd:GdVO4 laser with V3+:YAG saturable absorber are presented to demonstrate the numerical simulation applicable.  相似文献   

15.
Output performances of passively Q-switched, composite Nd:YAG/Cr4+:YAG lasers that consisted of bonded, all-poly-crystalline ceramics Nd:YAG and Cr4+:YAG are reported. Laser pulses at 1.06 μm with 2.5-mJ energy and 1.9-MW peak power are obtained from a 1.1-at % Nd:YAG/Cr4+:YAG ceramics that was quasi-continuous-wave (quasi-CW) pumped with a diode laser. Single-pass frequency doubling with LiB3O5 (LBO) nonlinear crystal at room temperature yielded green laser pulses at 532 nm of 0.36-mJ energy and 0.3-MW peak power, with a conversion efficiency of 0.27.  相似文献   

16.
This work presents experimental results concerning a passively Q-switched intracavity frequencydoubled Nd:LuVO4/LBO green laser with a Cr4+:YAG saturable absorber operated at the wavelength of 0.53 μm. A maximal output power of 1.28 W was obtained at a pump power of 16.34 W, and peak power, pulse width as well as repetition frequency were 1.48 kW, 41 ns and 21 kHz, respectively.  相似文献   

17.
We demonstrated an efficient and compact, diode-pumped passively Q-switched Nd:YVO4 laser operation at 1.064 μm wavelength with high repetition rate, using Cr4+:YAG as saturable absorber, formed with a simple flat–flat resonator. The maximum CW output power of 4.05 W was obtained at the incident pump power of 8 W. For Q-switched operation, the maximum average output power was measured to be 1.4 W with the corresponding repetition rate of 200 kHz, the pulse width of 60 ns when the initial transmission of Cr4+:YAG crystal was 85%. The shortest pulse width of 12 ns, the largest pulse energy of 36 μJ and the highest peak power of 3 kW were obtained when the Cr4+:YAG crystal with an initial transmission of 60% was used.  相似文献   

18.
By using both V3+:YAG and Co:LMA saturable absorbers, a doubly passively Q-switched laser is realized for the first time. The shorter pulse with the higher peak power is generated in comparison to the singly passively Q-switched laser with V3+:YAG or Co:LMA saturable absorber. The experimental results shows that it is possible to obtain a shorter pulse with the higher peak power in a doubly passively Q-switched laser.  相似文献   

19.
We report on an efficient high-power passively Q-switched UV laser at 355 nm. We take into account the second threshold criterion and the thermal-lensing effect to design and realize a compact reliable passively Q-switched Nd:YVO4 laser with Cr4+:YAG as a saturable absorber. At an incident pump power of 16.3 W, the average output power at 1064 nm reaches 6.2 W with a pulse width of 7 ns and a pulse repetition rate of 56 kHz. Employing the developed passively Q-switched laser to perform the extra-cavity harmonic generations, the maximum average output powers at 532 nm and 355 nm are up to 2.2 W and 1.62 W, respectively.  相似文献   

20.
A passively Q-switched 1.06 μm laser with Cr4+:YAG saturable absorber by direct 879 nm diode pumping grown-together composite GdVO4/Nd:GdVO4 crystal to the emitting level was demonstrated in this paper. The characteristics of pulsed laser were investigated by using two kinds of Cr4+:YAG crystal with the initial transmissivity of 80 and 90%, respectively. When the T 0 = 90% Cr4+:YAG was used, an average output power of 1.59 W was achieved at an incident pump power of 10 W. The pulse width and repetition rate were 64.5 ns and 170 kHz, respectively. The thermal lens effect of laser crystal was analyzed.  相似文献   

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