Spectroscopic and laser properties of glassy NdLa pentaphosphates

Stoichiometric rare-earth pentaphosphate crystals are well known as attractive laser media because of their very high optical gain. Generation and amplification of light is achieved in very small volume, which is of special interest in integrated optics. However, it is troublesome to grow well-developed single crystals of desired dimensions. The aim of this work is to obtain the glassy state of this interesting material. Hundreds of small-size Nd/sub 0.5/La/sub 0.5/P/sub 5/O/sub 14/ single-crystal platelets grown in the laboratory are melted in a vitreous graphite crucible at 967 K. The crucible is kept in a neutral atmosphere of argon. The samples are carefully examined with x rays to confirm the glassy state. Disks and rods are then cut out of the bulk and polished to optical quality. As shown, stoichiometric media exhibits almost fluent transitions from induced emission through superfluorescence to amplified spontaneous emission