Splitting of single photons by an ordinary beamsplitter

Summary form only given. The author has recently demonstrated a metallic beamsplitter and ultraviolet photons from an argon ion laser. The main experimental difficulty is the high rate of accidental counts that result from fluorescence and similar effects. The accidental rate is proportional to the square of the incident laser intensity, while the effect of interest is proportional to the intensity itself. Thus coincidence measurements at sufficiently low incident intensities can reduce the accidental events to an acceptably small level. Roughly one event per day was observed in which an incident photon was split into two secondary photons by a metallic beamsplitter.