Physical, chemical, and optical properties of Er^3+-doped low Al(PO_3)_3/Al(H_2PO_4)_3 modified fluoroaluminate glasses for 27 μm application

Fluoroaluminophosphate glasses with various content of metaphosphate Al(PO3)3 or dihydric phosphate Al(H2PO4)3 were prepared, respectively, to study the change in physical, chemical, and optical properties of glasses for 2.7 μm application. The glass forming ability, thermal ability, and structural properties were investigated along with the Judd–Ofelt parameters. Absorption and emission cross sections were discussed based on the absorption and emission spectra. The glass forming ability and chemical stability were enhanced by introducing metaphosphate [Al(PO3)3] or dihydric phosphate [Al(H2PO4)3] into the fluoroaluminate glass. The density decreased with the introduction of increased phosphate composition, while the refractive index increased. The absorption coefficient of OH− at about 3 μm dropped noticeably when Al(PO3)3/Al(H2PO4)3 modified the fluoroaluminate glasses and an enhanced 2.7 μm emission was observed with an optimal content of phosphate composition. These results indicate that these fluoroaluminophosphate glasses with low metaphosphate Al(PO3)3 or dihydric phosphate Al(H2PO4)3 composition are promising candidates for 2.7 μm application.