The Ld Pulse Side-pumped Nd: Yag / Of Lbo Cavity Frequency Doubling Electro-optic Q-switched Green Laser Research

The acoustic-optic (A/O) Q-switched lasers have the feature of high repetition rate (normally can reach 200 kHz) and they are mostly used in industry. Their achievable pulse energy is limited because the maximum loss by the A/O-switch is only more than 80% for fundamental mode. Comparing to A/O Q-switch, the maximum loss of electric-optic (E/O) Q-switch can reach 100%. And the achievable energy is only limited by Amplified Spontaneous Emission. High pulse energy, short pulse length, high peak power pulsed are required in many applications of laser, this features can be meted by the E/O Q-switched lasers. as well as the 532nm green laser have many properties such as the short wave length, the high photon energy, the long transmission distance in water, sensitive for the human eyes et al, which make electric-optic (E/O) Q-switch 532nm pulsed lasers have become the research focus. Currently, the flash lamp pump or the end pump about electric-optic (E/O) Q-switch 532nm pulse lasers are both reported very much. While the short pulse length green lasers with side pump of LD were less reported. The main work of article can be summarized as follows:1. The physical basis of electro-optic modulator is described. The features of common electro-optical crystal such as KD* P, BBO, LiNbO3, RTP, LGS are discussed. The basic principles of Q-Technology are expounded from the output characteristics of pulse laser.The impact factors for electro-optic pulse laser parameters are analyzed from electro-optic Q-switch rate equation, such as photon number of resonant cavity, pulse peak power, the output pulse energy and energy efficiency, the time characteristics of output pulse. The optical path diagram of positive voltage and passive voltage of KD* P crystal is given. The principle of KD* P crystal electric-optic (E/O) Q-switch is described in detail.2. The characteristics of commonly nonlinear crystal LBO crystal and KTP crystal are described briefly. The factors impacting harmonic efficiency are analyzed from small-signal solution of steady-state coupled wave equations. The phase matching methods are also introduced.3. The output characteristics of LD pulse Side-pumped E-O Q-switched Nd:YAG green laser was researched at the low repetition frequency. When the incident pumping current was 108 A at the repetition frequency of 100 Hz, the largest single pulse energy was 8.12mJ with pulse duration of about 12.2ns, corresponding to the peak power as high as 0.625MW was obtained.4. The laser engraving machine system which adopted the laser as the pump source is introduced. The fundamental Gaussian beam focused intensity and focused spot size is analyzed. The power density of laser engraving machine was estimated. The photograph about the Crystal was got when the laser engraving machine system was working and the Crystal was engraved.