450 nm blue laser emission of an intracavity-doubled Nd:ASL crystal pumped by an extended-cavity tapered laser diode

摘要

Efficient laser emission on the quasi-3-level transition 4{sup left}F{sub}(3/2)→4{sup left}I{sub}(9/2) has been demonstrated in various Nd-doped laser materials in the last decade. Among them the Nd:ASL crystal: Nd{sub}0.05Sr{sub}0.7La{sub}0.25Mg{sub}0.3Al{sub}11.7O{sub}19 is of great interest since its 4{sup left}F{sub}(3/2)→4{sup left}I{sub}(9/2) transition corresponds to a laser line as low as 900 nm [1]. This would result in a blue emission at 450 nm by second harmonic generation in a non-linear crystal. Unfortunately, the absorption lines of Nd:ASL are narrow and located at 792 nm and 798 nm where no commercial high power laser diodes are available. Moreover, the quasi-3-level operation of this laser requires a high-brightness pump source to exceed the transparency intensity all along the crystal.