Theoretical And Experimental Study Of The Full Four-wavelength Solid-state Laser

All-solid-state multi-wavelength laser can achieve multiple wavelength laser output simultaneously or alternatively. It plays an important role in optical storage, optical display, laser medical treatment, laser micro machining and so on,for its low power consumption, small size, high efficiency, compact structure, convenient operation and maintenance. In this paper, LD side-pumped multi-wavelength laser is analyzed theoretically and researched experimentally. The main contens of this paper can be summarized as follows:1. The characteristics,applications and multiple access methods of multi-wavelength lasers are reviewed, the development of multi-wavelength laser in recent years is introduced.2.The physical optics characteristics and laser characteristics of the two common crystal Nd:YAG and Nd:YVO4 are analyzed; Drawing from the three wave interaction equation, phase-matching technique is discussed and researched at length. The main features of the three common nonlinear crystal KTP, BBO, LBO are summarized; The common methods of Q-swith are concluded, such as electro-optics Q-switch and3. Deducing from the inside temperature field of laser crystal which is cooled by constant temperature, the thermal lens effect and thermal induced birefringence effect are analysed, for the laser power is limited by these thermal effects; The thermal effects of nonlinear crystal are also analysed and some mitigation measures are suggested; A few of current measurement methods about thermal focal length are compared, and the ususal compensation methods are summarized; At last, one type of double-lens telescope thermal insensitive cavity is designed.4. LD side-pumped four-wavelength laser is studied experimentally. Firstly, th 1064nm,1319nm double-wavelenth Nd:YAG laser is studied. When the pumping current reached at 20.5A and the repetition frequency is 11 kHz, the maximum average output power of 1064nm laser is 12W. When the pumping current reached at 21A and the repetition frequency is 9.4kHz, the maximum average output power of 1319nm laser is 8.22W. The new method of using water switch to change which laser to output is proposed. Then, four wavelength laser are outputted alternatively and the maximum average output power are 571.3mW,2.75W,17.2W,1.5W at 660nm,1319nm,1064nm,532nm. When the water switch is filled with water, the three laser of wavelength at 660nm,1319nm and 532nm are obtained simultaneously. The maximum average output power are 200mw,2.34W and 76mW; At last, the effect of the frequency of acousto-optic Q-switch on output power and pulse width is studied experimetally.