Latest results on fluorescence in optical filter glass

Optical filter glasses are for example used in spectroscopy for light separation. For a good signal-to-noise ratio, the self-fluorescence of optical filter glass should be low. Different optical filter glasses are available for such an application: bandpass filters or longpass filters from UV to near IR light. We will present a measurement set-up for fluorescence measurements. Afterwards results for different optical filter glasses at 365 nm and 488 nm excitation will be shown. Besides other factors, fluorescence depends on impurities of the raw material of the glass which can slightly fluctuate resulting in different fluorescence levels for different melting campaigns. Thus, results for different melting campaigns will be shown. In addition fluorescence quantum efficiency (FQE) measurements for different filter glass types will be presented for the first time allowing an estimation of the fluorescence light level. With the help of FQE a ranking of filter glasses with respect of fluorescence level will be shown. This will enable users to estimate the amount of fluorescence depending on different filter glass types and different melting campaigns.