RTC SEMINAR
"Polarization of Radiation from Localized Sources"
Ozgur Mustecapliuglu
Dept. of Physics, Bilkent University (Ankara, Turkey)
June 1999
Abstract:
For ages, in classical optics, polarization is considered to be well-known
property of light as a measure of its spatial anisotropy and it is widely
used in spectroscopic and interferometric measurements. In contemporary
quantum optics, new uses of polarization as discrete degrees of freedom
in the context of entangled states and qubits for quantum communications
and computations are discovered and attracted great deal of attention.
When the light intensity is low and very few photons are detected in
optical systems, then the meaning of polarization for photons becomes
a subtle one. In this talk, a systematic study of polarization properties
of radiation at an arbitrary distance from a localized source will be
presented. It will be shown that the polarization can be associated with
photons as a spin quantum number. This will be exploited to construct
position dependent coherency matrix which contracts into conventional
polarization matrix at far zone. General construction of Stokes operators
using the coherency matrix will be discussed. Description of communication
between the source and radiation in terms of conservation of angular momentum
will be given. Differences in the interpretation of polarization at near and
far zones of radiation for both classical and quantum light will be pointed
out. This treatment can have far reaching consequences in different optical
branches ranging from near field optics to quantum networks.
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