PHOTON NOISE - OBSERVATION, SQUEEZING, IN TERPRETATION

A review of modern concepts of photon noise (PN), which is observed ev en in the case of an ideal laser, is presented. The methods of transfo rmation, squeezing, and nondestructive observation of PN, are describe d. The optical nondestructive methods seem to be very important for th e interpretation of PN. The experiments with PN suppression by negativ e electron feedback are analysed in detail with two alternative approa ches, which could be called the a priori and aposteriori concepts. Acc ording to the first approach, PN exists in the laser beam from the beg inning while according to the second one it appears only in the detect ors. The theory based on the a priori concept predicts the squeezing o f the in-loop field-in contrast to a posteriori concept. Several possi ble crucial experiments based on the nondestructive methods are discus sed.