Abstract

Recently, we have developed a Nd:YAG ceramics with high optical quality [1]. The YAG ceramic allows high neodymium-ion doping to overcome low absorption cross-section. Table 1 shows the absorption coefficient of a 0.9 at.% Nd:YAG single crystal and Nd:YAG ceramics (1.1, 2.4, 4.8, and 9.1 at.%) in the 808 nm region. The 9.1 at.% Nd:YAG ceramic has about 10 times higher absorption coefficient than 0.9 at.% Nd:YAG single crystal. The laser chip was made from aYAG ceramic with 4.8 at.% Nd³⁺ doping level, cut to a 1.61 mm thickness. In an only polished chip Nd:YAG ceramics, single mode oscillation power of 213 mW with LD pump power of 1.6 W and a laser threshold of 334.6 mW was obtained. The slope efficiency was 17.6 %. Fig. 1 shows the longitudinal modes of the Nd:YAG ceramics laser with 200 mW output power.

© 1998 IEEE