| Lasers in the range of 2μm can be widely used in densely populated areas for its eye-safe characteristic. Lasers with the wavelength of 2μm have low loss when transmit in the atmosphere, it has good atmospheric transmission characteristics, thus it is often applied in ladar, medical, laser ranging, and photoelectrical countermeasures.Meanwhile, 2μm lasers can serve as pump sources for mid-IR optical parametric oscillators(OPOs), to generate laser output in the range of 3-12 μm. Therefore, it has practical application significance to obtain high-quality laser of 2μm wavelength.For the experimental study of dual-end-pumped Ho:YAG laser, we determined the pump wavelength of Ho:YAG laser based on the absorption spectra of Ho:YAG crystal, and determined the range of output wavelength of Ho:YAG laser by the emission spectra of Ho:YAG crystal.Because of the thermally induced refractive index gradient caused by the interaction of pump light and Ho:YAG crystal, the temperature distribution and thermal lens effect of Ho:YAG crystal were theoretical analyzed.The experimental study of dual-end-pumped Ho:YAG laser was carried out based on the theoretical calculate above.By using output couplers with different transmittance, the influence of different Q-switches on the laser output characteristics was investigated.By taking advantage of an electro-optic modulator, under the repetition frequency of 1k Hz, we obtained laser pulse with single pulse energy of 17.3m J, corresponding to a pulse width of 16.9ns and a peak power of 1.024 MW, and it was a good performance. Then we did the experimental study of passively Q-switched laser which employed a Cr2+:Zn S saturable absorber, the doubly Q-switched experiment that used both an active Q-switch and passive saturable absorber Q-switch in the same cavity was carried out at last. The experiment results of the three different kinds of Q-switches were comparative studied. Besides, the pulse width, peak power, and pules profile of the doubly Q-switched laser were investigated.We reduced the pulse width substantially by the way of double Q-switching,and finally obtained pulse waveform almost perfectly symmetrical. |
PDF Full Text Request