A Photon Counting Apparatus for Kinetic and Spectral Measurements

Abstract

An apparatus is described for spectral and time response measurements in luminescent materials using photon counting techniques. The system's most novel feature is its ability to switch rapidly between spectral and kinetic modes. Using the delayed coincidence method, with its excellent sensitivity, the kinetic measurements can be made easily with bandpasses as small as 0.5 meV. The system uses laser excitation pulsed by an acousto-optic modulator (3 nsec 1/e time) and for very fast measurements, mode locked pulses are used (0.25 nsec wide). Luminescent time decays from 1 nsec to 80 μsec can be obtained. The delayed coincident technique has been adapted to provide time resolved spectra with small time windows (<10 nsec) in the same range.