Abstract

We are trying to develop high efficiency sources of single photons for quantum optics applications. We aim to do this by isolating single dye molecules thus limiting our maximum emission per pump pulse to a single photon. We have previously reported our method to analyse the emission from dye molecules [1]. A dye solution (Rhodamine 6G dissolved in propylene carbonate) is place between two dielectric mirrors. The structure forms a λ/2n thick microcavity with a light emitting dye layer, approximately 40 nm thick, in the centre. The microcavity narrows the spontaneous emission spectrum of the dye molecules so a high signal-to-noise ratio is achieved by efficient filtering. The single molecule regime is reached by using very dilute (10^–9M) dye solutions and a small illumination volume defined by the 40nm thick dye layer and a 6µm diameter confocal collection scheme. We can monitor the dynamics of the dye molecule emission over a wide range of time, from nanoseconds to seconds, with intensity correlation measurements. We can extract information of the excited state lifetime, the triplet state lifetime and population, the mean number of molecules illuminated and the diffusion time through the pump light focus.

© 2000 IEEE