Spectral Hole Burning: Data Storage and Processing

At very low temperatures, the spread in the different environments of matrix embedded dye molecules results in an inhomogeneously broadened S1 ← S0 band. Spectroscopic techniques based on the appearence of optical zero phonon lines, such as fluorescence line narrowing, spectral hole-burning, and single molecule spectroscopy provide an experimental resolution limited by the homogeneous linewidth. From the investigation of the homogeneous line width as a function of different parameters (time, temperature) information on the guest host interactions responsible for the observed linewidth is obtained. Spectrally narrow features are extremely sensitive probes for external perturbations, such as electric fields, magnetic fields, or hydrostatic pressure.