Ld Side-pumped Solid-state Multi-wavelength Lasers

All-solid-state multi-wavelength lasers have wide scope of applications in many fields than single wavelength lasers, because it is of the unique advantages of multi-wavelength lasers emission simultaneously or alternatively. With the development of modern clinical medicine, all-solid-state multi-wavelength laser has irreplaceable role, and it will gradually replace multi-wavelength gas and dye laser because of its small size, high efficiency, high energy and environmental protection, long lifetime, etc., so the potential market demand is quite large. This paper focused on the study of "LD side-pumped multi-wavelength all-solid-state lasers output simultaneously" , then made theoretical research on frequency conversion of different-wavelength lasrs and multi-wavelength acousto-optic Q. On the basis of designing the optimal cavity, the experimental research on the continuous and quasi-continuous three-wavelength lasers (red, yellow and green) has been done. The preliminary experimental research about simultaneous output of fundamental and second harmonic wave has also been studied, then the theoretical calculation and simulation about compensation of the thermal lens in the condition of high-power has been researched as well. The main contents of the paper are listed as follows:1. Reviewed the methods of obtaining multi-wavelength lasers, the research status of all-solid-state multi-wavelength laser crystals and devices, the application of multi-wavelength lasers in medicine, and generalized the main content, purpose and significance of this paper.2. Based on the coupled-wave equation, the sum and double frequency conversion efficiency of small and large signals in the approximation of plane wave and Gaussian wave were derived. The relationship of phase-matching angles in different phase-matching conditions and the impact of the temperature of sum frequency crystal on phase-matching angle were also calculated and simulated. After that, the impact of phase-matching conditions and temperature changes in sum frequency crystal on effective nonlinear coefficient were calculated and simulated as well.3. Based on the rate equation, the multi-wavelength acousto-optic Q-rate equation was established, the impact of acousto-optic Q-technology on the multi-wavelength laser output characteristics has also been studied, including the different wavelengths emitted simultaneously from one crystal and emitted from different crystals. 4. The continuous and quasi-continuous output characteristics of red (660nm), yellow (589nm), and green (532nm) laser were researched. A new "T" type of yellow composite cavity laser systems was designed, and the impact of laser cavity parameters on the system performance was also analyzed. On this basis, a cruciform structure composite cavity was developed, and a red, yellow and green multi-wavelength laser output with high-power, high beam quality and stable performance was realized .5. The red (660nm), green (532nm) and infrared (1064nm and 1319nm) multi-wavelength lasers output characteristics were mainly studied. The impact of different cavity mirror transmittance and the intra-cavity loss of different wavelengths on the multi-wavelength laser output characteristics were analyzed theoretically. Different types of modules were used to obtain multi-wavelength laser output in the experiment to , and the compensation of the thermal lens effect by the telescope system in the condition of high-power was analyzed theoretically as well.