Nd pentaphosphate lasers

Nd pentaphosphate is a crystalline material with very high Nd concentration (30 times higher than 1 % Nd doped YAG) and yet low concentration quenching. It is an excellent material to construct optically pumped, miniaturized, low threshold lasers, oscillating at 1.05sm. Material characteristics including spectroscopic properties relevant to laser properties are reviewed. Experiments on pulsed and CW laser action in this material including the recent achievement of a miniaturized fibre laser with only 12×12 um cross section are summarized.