Laser spectrophotometer for measuring differential cross sections of biological particles

A tunable laser spectrophotometer is described that can accurately measure the differential scattering cross sections of small particle suspensions in the visible spectral range. The instrument was calibrated using a suspension of latex spheres of known size and index of refraction. By increasing the intensity of the illuminating laser, it should be possible to study differential scattering processes of individual particles on a microsecond time scale.