Laser-induced fluorescence in fused silica and other optical materials

Laser induced fluorescence has been observed in off the shelf optical materials when pumped with a copper vapor laser at 510 nm and 578 nm as well as when pumped with a doubled Nd:YAG laser at 532 nm at average irradiance levels of 80 and 10 watts/cm 2 respectively. The fluorescence spectra was observed using an avalanche photodiode photon counter and ranges from the excitation wavelength to 1100 nm. Lifetimes ranging from less than a microsecond to a millisecond, depending on the type and grade of optical material. The fluorescence is attributed to both impurities as well as intrinsic defects in the material. Fluorescence is observed in every type of material tested including UV grade fused silica, although such materials fluoresce several orders of magnitude less than standard optical grade materials such as flints and crowns.