Low Repetition Frequency LD Side-Pumped Nd:YAG Laser Without Water Cool

In this paper, the development and current research of low repetition frequency laser without water cool are summarized and analyzed at home and abroad. Comparing with water cool laser diode (LD) pumped solid-state lasers, conduction-cooling is used in diode pumped solid-state lasers without water cool. It has eliminated the huge complex water-cool system. And it has become a focus in the field of laser technology, due to the advantages of compactness, portability, and environmental fitness etc. Without water cool lasers are widely used in lots of special fields at the same time, such as the applying in the area of air-borne and satellite-borne laser remote sensing measurement. People pay more and more attention in the research of the large energy and low repetition frequency without water cool LD side-pumped solid-state lasers.According to improving output laser beam quality and laser output performance, a special structure of without water cool double semi-circumferential laser diode array (LDA) side-pumped was proposed and designed in the low repetition frequency and without water cool LD side-pumped electro-optic Q-switched Nd:YAG laser. Pumping intensity distribution, cooling temperature distribution and thermal effects of without water cool double semi-circumferential LDA side-pumped Nd:YAG lasers were researched on numerical and simulation. The rationality of without water cool double semi-circumferential LDA side-pumped structure was analyzed. Hot-insensitive resonant cavity was designed. Laser output pulse energy and pulse width were calculated. The design and experimental research of low repetition frequency LD side-pumped electro-optical Q-switched Nd:YAG laser based on without water cool double-side semi-circular LDA side-pumped structure was completed.Through the experimental research, laser pulse output energy of 178mJ and pulse width of 8.25ns of narrow pulse Q-switch quasi-fundamental mode at 1064nm was obtained when the frequency was 20Hz, LDA injection current was 100A and pump energy at 808nm was 1200mJ. Optical-optical conversion effective was 14.8%. The laser beam quality factor was M~2≈3.2, and divergence angle was 2.78mrad. The experimental results show that it can operate without water-cool, and achieve laser output of good beam quality based on without water cool double-side semi-circular LDA side-pumped structure.