Abstract: A crystal filter and a method of making a crystal filter capable of transmitting radiation within a particular pass band is disclosed. The crystal filter is particularly appropriate for a UV detection system, where the pass band is between about 200 to about 350 nm. A UV detection system incorporating the crystal filter is also described. One embodiment of crystal filter is formed from a single-crystal transparent host, such as a fluoride host, codoped with lanthanide or actinide fluorides and lanthanide or actinide nitrides, oxides, borides, carbides or hydroxides. Filter crystals according to the present invention can be grown by various crystal growth methods, including Czochralski and Bridgeman crystal growth methods.

Abstract: A laser crystal for a solid state laser with tunable emission in the ultraviolet wavelength region. The crystal is of trivalent cerium cations activated (doped) into the colquiriite crystal structures, such as LiCaAlF.sub.6 (LiCAF) and LiSrAlF.sub.6 (LiSAF). The crystal is grown along a well-defined axis by seeded crystal growth techniques to provide starting material which is fabricated along the preferred polarization direction with high yields. A primary crystal growth issue for cerium activated colquiriites is the charge compensation mandated by the substitution of the trivalent cerium ion for divalent strontium, which is located in the only site large enough to support the cerium cation. Charge compensation with monovalent or divalent cations is utilized to optically stabilize the colquiriite crystal and produce a solid state laser host which is less susceptible to color center or optically-induced defect formation during the ultraviolet lasing or ultraviolet excitation mechanisms.