MEASUREMENTS OF PHOTON CORRELATIONS IN A LASER BEAM NEAR THRESHOLD WITH TIME-TO-AMPLITUDE CONVERTER TECHNIQUES

A procedure for the measurement of intensity correlations of the type :I^(x,t)I^(x,t+τ): and :I^(x,t)×I^(x,t+τ1)I^(x,t+τ2): with the use of a time-to-amplitude converter is developed. The procedure is used to measure second- and third-order intensity fluctuation correlation functions of the optical field produced by a gas laser operated at various levels near its threshold of oscillation. The results are shown to be in agreement with the predictions of laser theories. © 1969 The American Physical Society.