Characteristics of laser-induced gratings in Pr^3+- and Eu^3+-doped silicate glasses

Four-wave mixing techniques are used to produce laser-induced gratings in Pr3+-doped silicate glasses for the first time to our knowledge. The characteristics of the laser-induced grating are investigated and compared with those found in Eu3+-doped silicate glasses. An attempt to form a laser-induced grating in an Er3+-doped silicate glass was made. Under excitation conditions similar to those in previous experiments, no laser-induced grating could be produced. Differences between the samples are discussed in terms of high-energy phonons, which are emitted when the rare-earth ion relaxes nonradiatively. Temperature dependences of the laser-induced grating signal intensity are investigated in Eu3+-doped silicate glasses, and the results are compared with theoretical predictions.