Nonphotochemical hole burning in Zn-TBP/PMMA. Unusual burning kinetics and very narrow holewidth limit Original Research Article

Nonphotochemical hole burning (NPHB) kinetics was investigated on PMMA samples doped with Zn-TBP molecules. The combination of a very low triplet state saturation threshold of Zn-TBP and a large dispersion of NPHB quantum efficiencies produces very specific hole burning kinetics. The most interesting effects are: (a) very high sensitivity of hole width and burning quantum efficiency to burning power; (b) narrow persistent hole width limit as compared to transient hole burning and 3-pulse photon echo data. The experimental results are interpreted in terms of a kinetic hole burning model which includes a broad distribution of the NPHB quantum efficiencies, the triplet state saturation effect, and the influence of spectral diffusion.