Abstract

In 1989 Moerner and Kador succeeded in detecting single molecules in absorption with a sophisticated double modulation technique [1]. A much better signal to background ratio was obtained by Orrit and Bernard [2] using the method of fluorescence excitation. Single molecule spectroscopy allows to study the distribution of molecular properties and not only the statistical average which is generally observed. Wild, Güttler, Pirotta and Renn have investigated the linear as well as the quadratic Stark effect of pentacene in a p-terphenyl crystal [3]. Results on the linear Stark effect in a polymer were obtained by Orrit et al. Some of their investigated terrylene molecules showed a surprisingly strong induced dipole moment [4].

© 1992 Optical Society of America