NONCLASSICAL LIGHT

Properties of the non-classical light (NCL) are considered with the em phasis on experimentally observed signatures, which are underlied by t he well-known Mandel's formula relating the statistics of photon count s to that of the light incident on the detector. A systematic operatio nal approach is presented to study the NCL using two parallel sets of numbers measured: probabilities of photon counts {p(m)} and normalised factorial moments of counts {g(k)}. Two particular examples are exami ned in detail: a 'heated' squeezed vacuum and a 'heated' one-photon st ate. An alternative method is proposed to discover weak non-classicali ty using 'generalised' moments {a(k)(s)}. The influence the linear abs orption (amplification) and the beam-splitting exert on the NCL, and t he relation between the NCL and the absolute calibration of photodetec tors are considered. The conditions are round under which the beam-spl itter realises a mathematical operation of superposition of two one-mo de fields, which is useful in studying the NCL.