A tunable light pulse generator to investigate properties of photodetectors

This paper presents the development of a tunable light pulse generator built to measure the quantum efficiency of photodetectors under continuous or pulsed (20 ns FWHM) illumination as a function of wavelength in the VIS-UV region. Quantum efficiencies of PMTs, PIN photodiodes and avalanche photodiodes have been measured. With the present setup, no significant differences between the dynamic (/spl sim/10'000 photons) and DC responses of PIN photodiodes were observed down to 300 nm.