We present a model of passively Q-switched Raman lasers by utilizing the rate equations. The intracavity fun-damental photon density, Raman photon density and the initial population-inversion density of the gain mediu...We present a model of passively Q-switched Raman lasers by utilizing the rate equations. The intracavity fun-damental photon density, Raman photon density and the initial population-inversion density of the gain medium are assumed to be of Gaussian spatial distributions. These rate equations are normalized by introducing some synthetic parameters and solved numerically, and a group of general curves are generated. Prom these curves we can understand the dependence of the Raman laser pulse characteristics on the parameters about the pumping, the gain medium, the Raman medium and the resonator. An illustrative calculation for a passively Q-switched Nd^3＋：GdVO4 self-Raman laser is presented to demonstrate the usage of the curves and related formulas.展开更多
We demonstrate a diode pumped Yb：LuVO4 laser that can be passively Q-switched by a Cr^（4＋）：YAG saturable absorber having an initial transmission as high as 99.3%.A maximum pulsed output power of 2.35 W is generat...We demonstrate a diode pumped Yb：LuVO4 laser that can be passively Q-switched by a Cr^（4＋）：YAG saturable absorber having an initial transmission as high as 99.3%.A maximum pulsed output power of 2.35 W is generated at a repetition rate of 285.7 kHz,approaching or very near the intrinsic upper limit imposed by the recovery time of the Cr^（4＋）：YAG saturable absorber,and the resulting pulse energy,duration and peak power are,respectively,8.2μJ,39.2ns and 0.209kW.展开更多
Numerical simulation of diode-pumped Q-switched Nd:YAG laser leading to the generation of eye-safe signal in singly resonant Intracavity Optical Parametric Oscillator (IOPO) is presented. Starting from rate equations,...Numerical simulation of diode-pumped Q-switched Nd:YAG laser leading to the generation of eye-safe signal in singly resonant Intracavity Optical Parametric Oscillator (IOPO) is presented. Starting from rate equations, the time dependent laser equations have been solved numerically, whereas the space-dependent OPO equations analytically. Our results show that 1.4 J diode laser (810 nm) pulse with 200 msec width, delivers 30 mJ Nd:YAG laser (1064 nm) pulse with 5 n-second width. This Nd:YAG laser further generates 9 mJ eye safe signal (1570 nm) pulse with 2.5 n-second width.展开更多
By modulating the pump current, we developed a passively Q-switched diode-pumped all-solid-state laser with a repetition rate stabilized up to 10^-7. It was experimentally demonstrated that the stability could sustain...By modulating the pump current, we developed a passively Q-switched diode-pumped all-solid-state laser with a repetition rate stabilized up to 10^-7. It was experimentally demonstrated that the stability could sustain for an arbitrarily long time. Moreover, the stabilized repetition rates which were synchronized with different modulating frequencies were tuneable in a wide range, by adjusting the period of the pumping cycle only. The output single-pulse energy was also stabilized, which was independent on the pump power after reaching a saturable value.展开更多
With MoS2 as saturable absorber, passive Q-switching and Q-switched mode-locking operations of a Tm-doped calcium lithium niobium gallium garnet（Tm:CLNGG） laser were experimentally demonstrated. The Q-switched laser...With MoS2 as saturable absorber, passive Q-switching and Q-switched mode-locking operations of a Tm-doped calcium lithium niobium gallium garnet（Tm:CLNGG） laser were experimentally demonstrated. The Q-switched laser emitted a maximum average output power of 62 mW and highest pulse energy of 0.72 μJ. Q-switched mode locking was also obtained in the experiment. The research results will open up applications of MoS2 at the mid-infrared wavelength.展开更多
This paper presents a Doppler passive location method for moving targets with fixed single station using the Doppler frequency shift and time difference information.First,based on the relationship between frequency sh...This paper presents a Doppler passive location method for moving targets with fixed single station using the Doppler frequency shift and time difference information.First,based on the relationship between frequency shift and path difference,the virtual path difference is calculated from the measured value of Doppler frequency shift by means of mean value correction.Then,under the assumption that the target is moving at a constant speed along a straight line,two coaxial virtual double base arrays are constructed by using the moving track of the moving target based on the method of fixed period time difference.On this basis,the moving distance of the moving target can be calculated by using the ratio relationship between the frequency difference and the radial distance between the two adjacent detection points in the middle of the array,and the linear solution of the two double base path difference positioning equations.At this point,the relative coordinate position of the moving target can be obtained by directly using the linear solution of the double base path difference positioning equation again.展开更多
基金Project supported by the National Natural Science Foundation of China （Grant No 60478017）, the Science and Technology Development Program of Shandong Province, China and the Scientific Research Starting Foundation for Returned 0verseas Chinese Scholars, Ministry of Education, China.
文摘We present a model of passively Q-switched Raman lasers by utilizing the rate equations. The intracavity fun-damental photon density, Raman photon density and the initial population-inversion density of the gain medium are assumed to be of Gaussian spatial distributions. These rate equations are normalized by introducing some synthetic parameters and solved numerically, and a group of general curves are generated. Prom these curves we can understand the dependence of the Raman laser pulse characteristics on the parameters about the pumping, the gain medium, the Raman medium and the resonator. An illustrative calculation for a passively Q-switched Nd^3＋：GdVO4 self-Raman laser is presented to demonstrate the usage of the curves and related formulas.
基金Supported by the National Natural Science Foundation of China under Grant No 11574170
文摘We demonstrate a diode pumped Yb：LuVO4 laser that can be passively Q-switched by a Cr^（4＋）：YAG saturable absorber having an initial transmission as high as 99.3%.A maximum pulsed output power of 2.35 W is generated at a repetition rate of 285.7 kHz,approaching or very near the intrinsic upper limit imposed by the recovery time of the Cr^（4＋）：YAG saturable absorber,and the resulting pulse energy,duration and peak power are,respectively,8.2μJ,39.2ns and 0.209kW.
文摘Numerical simulation of diode-pumped Q-switched Nd:YAG laser leading to the generation of eye-safe signal in singly resonant Intracavity Optical Parametric Oscillator (IOPO) is presented. Starting from rate equations, the time dependent laser equations have been solved numerically, whereas the space-dependent OPO equations analytically. Our results show that 1.4 J diode laser (810 nm) pulse with 200 msec width, delivers 30 mJ Nd:YAG laser (1064 nm) pulse with 5 n-second width. This Nd:YAG laser further generates 9 mJ eye safe signal (1570 nm) pulse with 2.5 n-second width.
基金This work was partly supported by the Shanghai Pri-ority Academic Discipline, the National Key Project forBasic Research (No. TG1999075204) the NationalNatural Science Foundation of China (No. 10374028).
文摘By modulating the pump current, we developed a passively Q-switched diode-pumped all-solid-state laser with a repetition rate stabilized up to 10^-7. It was experimentally demonstrated that the stability could sustain for an arbitrarily long time. Moreover, the stabilized repetition rates which were synchronized with different modulating frequencies were tuneable in a wide range, by adjusting the period of the pumping cycle only. The output single-pulse energy was also stabilized, which was independent on the pump power after reaching a saturable value.
基金supported by the National Natural Science Foundation of China (Grant Nos. 61008018 and 11421064)the National Basic Research Program of China (Grant No. 2013CBA01505)
文摘With MoS2 as saturable absorber, passive Q-switching and Q-switched mode-locking operations of a Tm-doped calcium lithium niobium gallium garnet（Tm:CLNGG） laser were experimentally demonstrated. The Q-switched laser emitted a maximum average output power of 62 mW and highest pulse energy of 0.72 μJ. Q-switched mode locking was also obtained in the experiment. The research results will open up applications of MoS2 at the mid-infrared wavelength.
文摘This paper presents a Doppler passive location method for moving targets with fixed single station using the Doppler frequency shift and time difference information.First,based on the relationship between frequency shift and path difference,the virtual path difference is calculated from the measured value of Doppler frequency shift by means of mean value correction.Then,under the assumption that the target is moving at a constant speed along a straight line,two coaxial virtual double base arrays are constructed by using the moving track of the moving target based on the method of fixed period time difference.On this basis,the moving distance of the moving target can be calculated by using the ratio relationship between the frequency difference and the radial distance between the two adjacent detection points in the middle of the array,and the linear solution of the two double base path difference positioning equations.At this point,the relative coordinate position of the moving target can be obtained by directly using the linear solution of the double base path difference positioning equation again.
