The scattering of quanta as a consequence of accidental events.

Karl K. Darrow

Jean Ullmo

Jacques Moret‐Bailly

Incoherent emissions of light by a gas require collisions of molecules, while coherent emissions, at low pressure, are amplifications of pre-existing rays. At very low pressure, very accidental collisions of atoms of an excited gas initiate flare-ups, and Raman pumping of the gas by a temporally incoherent ray of light absorbs molecular quanta without other energy diffusion.

Guido Bacciagaluppi, Antony Valentini

J. D. Franson

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.

M. Leon