With the development of laser technology, all-solid-state blue laser can be applied in high density optical data storage, color display, underwater imaging and detecting, laser medicine, laser micro-processing, laser cooling, high-resolution laser printing and so on. For the all-solid-state cw single-frequency laser, it has many merits such as good power stability and frequency stability, narrow linewidth, tunable frequency, lower noise, so it can be applied in scientific research, instrument, optical communication, super-long-range, super-high-precision, super-high-sensitivity detection, optical holography, interference, optical storage, absolute frequency stability and absolute frequency standard. For the all-solid-state cw single-frequency blue laser, it can be applied high-precision laser measurement, biological technology, ultra-violet frequency-standard, scientific research and so on.Based on the research character and the studying foundation, we start the investigation of high-power all-solid-state cw single-frequency blue laser, and the method is that using the Nd:YAG for laser crystal to obtain the 946 nm laser, then obtain the 473 nm blue laser by intra-cavity frequency doubling technology. We carried out a series of research jobs as follows.1. In theory we analysised the characters of quasi-three-level of Nd:YAG laser operating on 946 nm by the rate equation including energy transfer upconversion, and the result shows that the energy transfer upconversion effect can influent the laser performance such as increase the threshold pump power and reduce the output power and so on. For the quasi-three-level laser system, it has some natures such as serious reabsorption losses, lower stimulated-emission cross section, and serious energy transfer upconversion effect and so on. The theoretical result also shows that the reabsorption losses is indirect proportion to the temperature and length of laser crystal and the spot radius of pump beam in laser crystal. Besides, the result shows that the energy transfer upconversion effect (or the ions including energy transfer upconversion process) is indirect proportion to the laser conversion efficiency, including the temperature of laser crystal, the transmission of output coupler and frequency doubling efficiency.2. In theory we discussed the thermal effect of laser crystal in detail, including thermal lensing effect, thermal-induced diffraction losses and the thermal-induced depolarization effect. Since the energy transfer upconversion effect can make the thermal effect of laser crystal more serious and the thermal effect indued by energy transfer upconversion effect is related to the laser conversion, the whole fractional thermal loading is related to the laser conversion and the thermal lensing effect, thermal-induced diffraction losses and the thermal-induced depolarization effect are also related to the laser conversion.3. Based on the theoretical analysis, in experiment we designed a six-mirror ring cavity, and inserted a Brewster plate into cavity as the isotropy of Nd:YAG crystal. We inserted a half wave plate and a TGG crystal that compose of an optical diode which can make the laser unidirectional operating, that make the output laser operating in single frequency. To reduce the reabsorption losses of Nd:YAG laser crystal, we decreased the temperature of Nd:YAG and optimized the length of it, besides, we also used a laser diode with fiber-core diameter of 400mm for pump source. Considering the thermal effect induced by energy transfer upconversion effect, we optimized the cavity and the transmission of output coupler. As a result of it, an output power of 1.5 W cw single frequency 946 nm laser was obtained.4. Based on the cw single frequency 946 nm laser, and inserted the PPKTP frequency doubling crystal into cavity to obtain the cw single frequency 473nm blue laser. To improve the frequency doubling efficiency and considering the thermal lensing effect induced by energy transfer upconversion effect, we optimized the laser cavity length, the temperature of PPKTP and the length of it, finally we obtained an output power of 1.01 W cw single frequency 473 nm blue laser. 5. In experiment, we investigated some 946 nm laser reflected from the Brewstwe plate that is because of the thermal-induced depolarization losses. According to the principle, we designed and obtained a dual-wavelength laser with an output power of 450 mW at 946 nm and an output power of 1.01 W at 473 nm.The creative works are as follows:1. We founded a theoretical model that the energy transfer upconversion effect (or the ions involving energy transfer upconversion process) is related to the he laser conversion efficiency, including the temperature of laser crystal, the transmission of output coupler and frequency doubling efficiency. It means that the thermal effect of laser crystal including thermal lensing effect, thermal-induced diffraction losses and the thermal-induced depolarization effect is also related to the he laser conversion efficiency. Based on the theoretical model, the theoretical calculation obtained a good agreement with the experimental result.2. In experiment, we obtained a cw single frequency 946 nm laser with an output power of 1.5 W. The long term power stability is less than±1%. After the laser was locked to the confocal Fabry-Perot cavity resonance, the measured frequency stability of 946 nm laser is better than±1.5 MHz.3. In experiment, we obtained a cw single frequency 473 nm blue laser with an output power of 1.01 W. The long term power stability is less than±1.8%. After the laser was locked to the confocal Fabry-Perot cavity resonance, the measured frequency stability of 473 nm blue laser is better than±4 MHz.4. Considering the thermal-induced depolarization effect of Nd:YAG laser crystal and suggesting a method of achieving dual-wavelength laser with the frequency doubling laser and fundamental-wave laser, we obtained a dual-wavelength laser with an output power of 450 mW at 946 nm and an output power of 1.01 W at 473 nm. |