Abstract

Nd³⁺:YAl₃(BO₃)₄ (NYAB) crystal is one of the best laser self-frequency doubling crystals reported up to now. It is an attractive crystal for construction of compact LD pumped lasers since the requirement for a separate doubling crystal alleviated. However, the crystal optical quality is often cited as the main cause for the high laser pumping threshold, low optical to optical conversion efficiency and bad laser beam mode. The main reason is that we incorporate Nd³⁺ ions, which has much bigger ion radii than that of Y³⁺ ions, into YA1₃(B0,)₄ crystals to take up the site of Y³⁺ ions. This is easier to produce deffects of lattice distortion, cloud, etc. So, we incorporate the Lu³⁺ ions, which is smaller than Y³* ions, into the crystal during the crystal growing to reduce the difference. This is called “Volume Compensation”. The Lu³⁺:Nd³⁺:YAl₃(BO₃)₄ (LNYAB) crystal had been grown in our lab before. The initial laser experiment showed that the properties of this crystal lasers were much better than those of NYAB self-frequency doubling lasers pumped by LD. All of LNYAB self-frequency doubling lasers pumped by LD can operate in TEM₀₀ Mode and the pumping threshold is less than one third of that of NYAB lasers. The laser efficiency also has increased greatly.

© 1996 Optical Society of America