Investigation On All-solid-state IR, Green And UV Laser With Short Pulse Duration

LD pumped solid state Q-switched lasers have become a focus in the field of lasers due to their advantages of compactness, high efficiency, long lifetime, high stability, and good quality of light beam, and etc. They are widely used in many fields, such as photoelectrics industry, military, medical treatment, scientific research, and etc. In order to obtain laer pulse with short duration, high peak power, high efficiency, and high stability, this dissertation has made experimental researches around LD pumped doubly Q-switched IR together with green lasers, and AO Q-switched ultraviolet (UV) lasers. A great improvement has been made in the fields of pulse compactness and symmetry. The main contents can be summarized as follows:1. The history, development and present conditions of LD pumped solid state lasers are reviewed, the Q-switched technology is summarized from all round, and the hot spots in this field research now and in the future are studied.2. Basing on the theory of AO Q-switching, passive Q-switching, and double Q-switching, the properties of LD diode pumped 1064nm laser with short pulse duration are analyzed, laser pulse with short pulse duration and high peak power is obtained. The characteristics of pulse duration and symmetry are analyzed in the three Q-switched lasers.3. Basing on the theory of nonlinear frequency doubling, sum-frequency and AO and GaAs double Q-switching, the properties of LD diode pumped 532nm laser with short pulse duration are analyzed, laser pulse with short pulse duration and high peak power is obtained. The pulse duration of the three Q-switched green lasers are measured, and the symmetry is analyzed. The pulse duration of doubly Q-switched green laser has been shortened to 3.2ns .4. According to the principle of nonlinear phase matching, and the technology of frequency doubling and sum-frequency, a diode-pumped all-solid-state ultraviolet laser at 355 nm with short pulse duration of 4.5ns, high average output power of 536mW, high stability and TEM00 mode. at the incident pump power of 15.65 W, and repetition rate of 20kHz, corresponding to an optical-to-optical efficiency of 11.4% from 1064nm to 355nm.5. With the basis of the thermal lens effect of the gain medium, choosing moderate transmission of output mirror and cavity length, a small beam waist of 1064nm laser is obtained, which is helpful for the frequency conversion efficiency. A 266nm laser with short pulse duration, high average output power of 216mW, high stability and TEM00 mode, at the incident pump power of 12.1 W, and repetition rate of 20kHz, corresponding to an optical-to-optical efficiency of 5.8% from 1064nm to 266nm. The pulse duration of 266nm laser has been shortened to 4ns.