NdLa pentaphosphate laser performance

Abstract

Laser operation is reported in a new crystalline material with high Nd content (2 × 1021 cm−3) whose concentration quenching is smaller than in other hosts. This material, NdLa pentaphosphate (Nd0.5La0.5P5O14) in the form of a 35-μm-thick crystal platelet was pumped with a pulsed Rhodamine 6G dye laser. The oscillation threshold with feedback from the uncoated surfaces was [inverted lazy s] 20 μJ of absorbed pump light. This indicates an optical gain coefficient of [inverted lazy s] 800 cm−1 corresponding to an excitation of more than half of the Nd ions in the material. This high gain resulted in a compression of the cavity mode spacing by a factor of 14. Using external mirrors, cw oscillation with a threshold of 25 mW absorbed power of an argon laser was achieved with a 1.4-mm-thick crystal. Measured parameters of the lasers are in good agreement with theory.