Abstract

One of the most promising fields for picosecond spectroscopy is resonant secondary emission, as by making use of this optical response there is no need to apply strong excitation or additional probing on the sample, which may disturb the processes under study. The introduction of a sensitive spectrochronography method [1] has made the temporal resolution of hot luminescence spectrum possible [2], providing thus a direct measure of the vibrational relaxation processes in the excited electronic state of an impurity centre. The physical situation is more intriguing when light-matter interaction cannot be considered in the perturbation approach and one has to use polaritons to describe the properties of the secondary spectrum [3]. Some special features in the temporal behaviour of the polariton luminescence spectrum of anthracene were revealed already in a nanosecond study [4]. Since the first report on picosecond luminescence kinetics [5] we have carried out a systematic study of polariton dynamics in anthracene crystals at low temperatures in order to distinct between the scattering/luminescence processes and to elucidate the effective decay channels of the primary excitations.

© 1984 Optical Society of America