Abstract

The problem of identifying the dynamical variable corresponding to the phase of a quantized electromagnetic field is as old as quantum mechanics and has led to a large number of different attempts. We have recently approached it operationally, by starting from typical measurement procedures for the phase difference in classical optics, and identifying the corresponding operators for a quantum field.^1,2 This leads to different operators foe different measurement schemes for the cosine and sine of the phase difference. The two operators commute for simultaneous cosine and sine measurements, but not when the two measurements are mutually exclusive. We have applied the formalism to several different quantum states and compared the predictions of our theory with those of Susskind-Glogower and with the Hermitian phase operator of Pegg-Barnett. We have also made measurements that cover a much wider range of light intensities than any previous ones.¹ In all cases, we obtain very good agreement between our theory and experiment.

© 1992 Optical Society of America