Optical Spectra and Kinetics of Single Impurity Molecules in a Polymer: Spectral Diffusion and Persistent Spectral Hole-Burning
Interim technical rept.
IBM ALMADEN RESEARCH CENTER SAN JOSE CA
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Using high efficiency fluorescence excitation techniques, optical spectra of single impurity molecules of perylene in a polyethylene matrix can be obtained at 1.5 K. Analysis of such spectra show a variety of spectral diffusion effects, including fast resonance frequency changes on the 1-100 MHz scale which lead to a range of apparent linewidths, as well as discontinuous jumps in the resonance frequency of 10-1000 MHz on a longer time scale. In addition, light induced changes in resonance frequency of a single molecule persistent spectral hole-burning have been conclusively observed by showing that the burning time decreases with increasing laser power. Surprisingly, hole- burned single molecule often spontaneously return to the original frequency in 1-100 s. Measurements of the burning time for a large number of hole-burning events for the same simple molecule yield an exponential burn time distribution, which is the first direct measurement to our knowledge for the stochastic kinetics of a single molecule.
- Atomic and Molecular Physics and Spectroscopy