Study On All-Solid-State 946nm Laser And Watt Level 473nm Laser

In this thesis, the theoretic and experimental study on laser diode(LD)end-pumped Nd:YAG cw 946nm laser were investigated. Regarding 946nm asfundamental wave, by using LBO as intracavity frequency doubling crystal, thesecond–harmonic of 473nm laser generated.LD pumped blue laser has many advantages, such as short wave length, highefficiency, compact configuration and high stability, so, it has broad applications inmilitary fields, fiber communications, sensitive detector,information storage, highspeed optical printing, etc. This thesis introduces many ways to generate blue laser,currently, the ordinary way to product blue laser is SHG from 946nm Nd:YAGquasi-three-level laser system. This thesis will focus on this sort of 473nm laser.In chapter 2, the inverted population of 946nm had been calculated from rateequation of quasi-three-level laser system, then, the 946nm Nd:YAG laser system wastheoretically studied and the threshold, output power and slope efficiency werenumerical calculated and simulated.The end-pumped thermal effect of laser crystal had been theoretically analyzedin chapter 3, a simple way to measure focus length of thermal lens had beenmentioned, and the technique to eliminate the thermal effect had been proposed. Byusing the ray matrix methods and parameter g, the parameters of linear cavity andthree mirrors folded cavity were well calculated.In chapter 4, a holistic project had been designed for the experiment, such aslaser crystal, frequency doubling crystal, pumping source and its focus lensing system,coating for every optical apparatus, all this work had made full preparations for theexperiment.The experiments about 946nm and 473nm have been done in chapter 5. Weemployed linear cavity and Nd:YAG rod as laser crystal, by using output mirror of T=5%, when the pump power was 24W, 5.11 W high stability 946nm laser wasachieved, with the output power fluctuation of less than 2% and the efficiency ofoptic-optic was 21.3%, the threshold was only 1.4W. We employed the same cavityand laser crystal, by using the LBO (which was type Ι phase matching at roomtemperature) as the frequency doubled crystal, when the pump power was 11W,982mW 473nm laser was achieved, whose threshold is only 0.7W and the efficiencyof optic-optic was 21.3%. By using detailed computer program simulation, wedesigned a dynamic stable resonator for the three mirrors folded cavity whose twowaists did not alter with the focus length of thermal lens, this will well guide our nextexperiment.There following innovation points:1. We employed linear cavity and ordinary Nd:YAG rod as laser crystal, whenthe pump power was 24W, 5.11 W high stability 946nm laser was achieved, with theoutput power fluctuation of less than 2% and the efficiency of optic-optic was 21.3%,the threshold was only 1.4W.2. We employed the same cavity and laser crystal as the 946nm laser, by usingthe LBO (which was type Ι phase matching at room temperature) as the frequencydoubling crystal, when the pump power was 11W, 982mW 473nm laser was achieved,whose threshold was only 0.7W and the efficiency of optic-optic was 21.3%.