A theoretical model based on rate equations for actively Q-switched Er<sup>3+</sup>-doped ZBLAN fiber laser is built. The operation behaviors and output characteristics of the actively Q-switched fiber laser at 2.8 μm are analyzed. Effects of some important laser parameters, such as pump power levels, reflectivity of the laser output coupler, fiber lengths, Er concentrations, etc., on laser output were investigated. The model and simulating results are useful for design and optimization of actively Q-switched fiber laser at 2.8-μm region.
We report a continuous wave (CW) all-solid-state Cr:LiSAF laser with a prism-controlled coupled-cavity. Broad-band tuning of 198 nm from 784 nm to 982 nm is demonstrated. The output power is always above 14 mW tuned from 825 nm to 975 nm and reaches the maximum value of 21.4 mW at 900 nm. Dual-wavelength operation is observed at the edge of the tuning range. The coupled-cavity passive loss is discussed and calculated to be 18%.
A general model has been developed for the optimization of the end-pumped solid-state lasers by including the effect of beam quality of the pump, and ellipticity of pump and oscillation beam into the overlap integrals. Previous models of mode-matching between oscillation and pump beam just consider of the ellipticity of pump beam, and assume the Gaussian oscillation beam to be circle TEM00 mode. Our model of mode-matching considers not only the ellipticity of the pump and oscillation beam, but also the angle of the long axis of the pump and oscillation beam. To illustrate the utility of the present model, an end-pumped Cr:LiSAF laser pumped is considered and the experimental results fit well with the theoretical results.
A 3A molecular sieve separation device was designed and mounted in a closed-cycled non-chain HF laser to separate the ground state molecule being produced in discharge region from gas stream in order to improve the stability of laser output energy. Experiments were carried out with several different discharge voltages and gas flow velocities, and the preliminary results show that the molecular sieve separation device could dramatically decrease the decay of output energy of HF laser while improving the laser energy stability.
SF<sub>6</sub> and C<sub>2</sub>H<sub>6</sub> are the working gas mixture of non-chain HF laser. In our work, we use a simple pumping circuit to study the influence of the electric field uniformity on the discharge characters. Three groups of electrodes with different designs have been manufactured, and different discharge characters have been got. We have analyzed the results qualitatively, and find that without preionization, uniform electric field is not the best choice to form a large volume discharge in strong negative gas such as SF<sub>6</sub>-based mixture; approximate uniform electric field may be its substitution. In such electric field the gap breakdown voltage decreases and discharge can perform much easily. The discharge channels away from the cathode surface can also diffuse together to form a large volume discharge to deposit the electric energy into the laser working gas.
The investigations of the XeF laser bumped by ultraviolet radiation have been studied for more than 20 years in Northwest Institute of Nuclear Technology (NINT Xi’an China). Up to now, several XeF laser devices were developed and an integrative experimental system has been set up which is comprised of a laser device, an electrical power supply, a high voltage trigger generator and a mixture gas supply device. Many key technologies were studied in detail and have been applied now. These technologies include section surface discharge, XeF2 photodissociation, synchronal trigger generating, double-sides optical pumping from opposite directions, active mixture gases supplying in real time, gases circulation, and so on. The XeF laser system operating on pulse repetition frequency (PRF) is up to 10 Hz. Two kinds of operating modes were applied. For the open gas flowing mode, the pulse energy of 3.2 J and the average power of 32 W at 10Hz is obtained. For the gases circumrotate mode, the average energy of 20 laser pulses is more than 0.5J.