Quantum Electronics and Laser Science Conference
Spectral diffusion of single impurity centers in crystals
W. E. Moerner, W. Patrick Ambrose
Abstract
Single-molecule detection and spectroscopy in solids has the potential for direct observation of the microscopic physics and chemistry of defects without multicenter averaging. Initial observations of the optical absorption spectra of a single pentacene molecule in p-terphenyl crystals achieved signal-to-noise ratios (SNR's) of 3-5 in a 1-Hz bandwidth and required intensities at the sample above the saturation intensity. Careful noise analysis of our detectors showed that little improvement in SNR could be expected with an absorption technique unless simple and reliable sources of squeezed light were available. Recent advances in fluorescence- excitation spectroscopy have removed this SNR limitation.3