Photoluminescence of terbium glass investigated by temperature and pressure dependence

The photoluminescence (PL) intensity from terbium glass either decreases or increases with temperature, depending on the wavelength of the excitation argon ion laser. The red shift of photoluminescence excitation (PLE) spectr um with increasing temperature is responsible for this behavior. The absorp tion spectra also indicates that the excitation resonance is shifting towar d lower energy with increasing temperature. At 300 K, the PLE spectrum unde r 3.6 GPa broadens relative to the one under ambient pressure but with peak position nearly unchanged, indicating that the temperature dependent shift of the excitation resonance is not caused by thermal contraction of the te rbium glass but by the fact that electrons have lower average ground state energy at lower temperature. (C) 1998 Elsevier Science Ltd. All rights rese rved.