A frequency response method for high speed spectrophotometry, which is characterized by simpler instrumentation and narrower frequency bandwidth than the stroboscopic method, is developed from freuency domain considerations of a transient process. Time-resolved emission spectra of Y2O2S:Tb and Y2O2S:Eu show that Tb3+ and Eu3+ undergo two and three different types of transient processes, respectively. These processes are assigned to transitions from 5Dj to 7F. Resolving power for time resolution is suggested as a new criterion for system evaluation and calculated for the frequency response and stroboscopic methods.
K. Doi and A. Toshinai, "Frequency Response Method of High Speed Spectrophotometry for Luminescent Materials," Appl. Opt. 9, 2762-2767 (1970)