We investigate a free monochromatic electromagnetic field which is in
the even or odd coherent state with thermal noise. The main tool in ou
r analysis is the characteristic function. We establish an alystic for
mula for an arbitrary correlation function. We point out the non-class
ical oscillations of the photon-number distribution and find its gener
ating function as well as the degree of purity of the field. We also e
xamine the squeezing properties and antibunching feature. Besides, the
usual quasiprobability densities are derived.