For demanding applications such as fluorescence detection, wavelength stability is absolutely critical to insure dependable results. Newport's fluorescence filters with Stabilife coating technology have much higher spectral stability than competitors. One of the critical factor affecting the spectral stability of an optical coating is film density. Unlike competitor's unstabilized metal oxide thick film coating with less film density which typically contributes to environmentally induced spectral shift of 2-5%, Newport's Stabilife coatings have a much higher density and lower void ratio and are therefore less affected by water absorption. They typically exhibit total wet-to-dry shifts of less than 0.02% of wavelength.