Optical Absorption of Single Crystals of Y3Al5O12and Y3Al5O12:Nd3+in the UV Fundamental Absorption Edge Region

Optical absorption curves for nominally pure and Ce 3+ doped single crystals of Y 3 Al 5 O 12 (YAG) have been measured in the region of 5 eV–7 eV at 292 K, 78 K and 10 K. The parameters of the Urbach rule have been determined referring to those optical absorption curves which are believed to be the fundamental absorption tail of YAG single crystals at these temperatures, respectively. Optical absorption measurements on single crystals of YAG:Nd 3+ (the concentration Nd 3+ L being 0.60 atm.%) have disclosed strong absorption spectra consisting of at least five Gaussian bands in the region of 5.0 eV–7.0 eV at 292 K and 78 K. These spectra have been interpreted to originate from the interconfigurational transitions 4 f 3 →4 f 2 5 d of Nd 3+ in YAG.