In this thesis, we perform fundamental spectroscopic studies of organic fluorescent chromophores (dyes) for temperatures from 1-10 Kelvins. We use confocal and wide-field fluorescence microscopy... Show moreIn this thesis, we perform fundamental spectroscopic studies of organic fluorescent chromophores (dyes) for temperatures from 1-10 Kelvins. We use confocal and wide-field fluorescence microscopy techniques. We analyzed the spectroscopic properties of well-known dyes, such as perylene, terrylene and dibenzoterrylene embedded in different solids. By doing this systematically, we correlate the presence of methyl groups in the host-crystal (Chapter 2) with the strong spectral diffusion of the resonant line, which lead to spectral broadening and frequency instabilities of the guest DBT. In contrast, the absence or substitution of methyl groups by chloride showed any of these effects. We found that the fluorescent properties of perylene in ortho-dichlorobenzene and terrylene in para-dichlorobenzene solids were those expected for the single quantum system. No reports of lifetime-limited excitation lines for perylene were ever reported till now. Even further, we report the coupling of an acoustic wave created by a macroscopic object to the optical response of a single molecule. The shot-noise limited sensitivity from the response of the single molecule to the displacement of the fork's prongs was found to be in the sub-nanometer regime. Perylene in o-DCB will be used to perform the single molecule all-optical transistor proposed in the introduction. Show less
