Transmission spectra of crystals at elevated temperatures for the calculation of internal radiant heat transport during crystal growth – Part 2: Spectra of YAG:Cr,YVO4:Nd and the bandgap variation of various materials

The transmission spectra in the range from 350 to 3500 nm of the two most complex materials with regard to radiant heat transport – YAG:Cr⁺⁴ and YVO₄:Nd – are reported for temperatures between 25 and 1310 °C. The extreme shift of the short wavelength cut‐off (band gap) of YVO4:Nd with temperature is shown in comparison to that of some other materials. In YAG:Cr⁴⁺ we found a light‐induced absorption band near 2000 nm besides a strong reduction of the transmission in the visible and the near IR with increasing temperature. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)