Abstract

Single crystals of p-terphenyl doped with the aromatic hydrocarbon terrylene represent a favourable system for single molecule spectroscopy at low temperatures. In the electronic origin of site X₂ very stable single molecule excitation lines are observed with peak fluorescence rates of up to 600.000 s⁻¹ at high excitation intensities. The fluorescence autocorrelation function can be recorded over ten orders of magnitude in time for a a single terrylene molecule. It displays the characteristic features of photon antibunching, Rabi oscillations and photon bunching and allows the determination of pure·dephasing times and of the triplet kinetics. The latter can also be analyzed from quantum jumps between the singlet and triplet state which could be observed directly for the first time in this system. Employing a pump-probe experiment [1] with two laser beams, we also could observe the dynamical Stark effect or light shift for a single molecule. These latter results comprise non-linear optics with a single molecule.

© 1996 IEEE