STRAY-LIGHT SUPPRESSION WITH HIGH-COLLECTION EFFICIENCY IN LASER LIGHT-SCATTERING EXPERIMENTS

We describe an optical system that we constructed to collect a large fraction of fluorescent light emitted isotropically from a cylindrical interaction region. While maintaining an overall detection efficiency of 9%, the system rejects, by more than 12 orders of magnitude, incident laser light along a single axis that intersects the interaction region. Such a system is useful for a wide variety of light-scattering experiments in which high-collection efficiency is desirable, but in which light from an incident laser beam must be rejected without resorting to spectral filters.