Ravi S. Singh

Operator for Optical Polarization

For monochromatic light propagating along z -direction, we define a polarization operator which is product of inverse annihilation operator for the x -linearly polarized mode and the annihilation o...

Degree of polarization in quantum optics through the second generalization of intensity

Classical definition of degree of polarization is expressed in quantum domain by replacing intensities through quantum mechanical average values of relevant number operators and is viewed as first generalization of Intensity. This definition assigns inaccurately the unpolarized status to some typical optical fields such as amplitude coherent phase randomized and hidden polarized, which are not truly unpolarized light. The apparent paradoxical trait is circumvented by proposing a new definition of degree of polarization in Quantum Optics through second generalization of Intensity. The correspondence of new degree of polarization to usual degree of polarization in Quantum Optics is established. It is seen that the two definitions disagree significantly for intense optical fields but coincides for weak light (thermal light) or for optical fields in which occupancy of photons in orthogonal mode is very feeble. Our proposed definition of degree of polarization, similar to other proposals in literature, reveals an interesting feature that states of polarization of optical quantum fields depend upon the average photons (intensity) present therein.

On the polarization of non-Gaussian optical quantum field: Higher-order optical-polarization

Abstract Polarization of light signifies transversal, anisotropic and asymmetrical statistical properties of electromagnetic radiation about the direction of propagation. Traditionally, optical-polarization is characterized by Stokes’ theory susceptible to be insufficient in assessing the polarization structure of optical quantum fields and, also, does not decipher the twin characteristic polarization parameters (‘ratio of real amplitudes and difference in phases’). An alternative way, in the spirit of classical description of optical-polarization, is introduced which can be generalized to deal higher-order polarization of quantum light, particularly, prepared in non-Gaussian Schrodinger Cat or Cat-like states and entangled bi-modal coherent states. On account of pseudo mono-modal or multi-modal nature of such optical quantum field, higher-order polarization is seen to be highly sensitive to the basis of description.

Generation of hidden optical-polarization: Squeezing and non-classicality

Abstract A monochromatic bi-modal coherent light, endowed with orthogonally polarized photons propagating collinearly, is allowed to impinge as pump field in degenerate parametric amplification. Generation of Hidden Optical-Polarized State is seen by non-zero values of Index of Hidden Optical-Polarization. Squeezing in Hidden Optical-Polarized State is demonstrated by recognizing a Squeezing Function of which departure from unit-value ensures the squeezing. Furthermore, the non-classical feature is witnessed by the ‘Degree of Hidden Optical-Polarization’ having value ‘greater than unity’.

Quasi-probability distribution functions for optical-polarization

Cahill-Glauber C(s)-correspondence is employed to construct Quasi-Probability Distribution Functions (QPDFs) for optical-polarization in phase space following equivalent description of polarization in Classical Optics. The proposed scheme provides pragmatic insights as compared to obscure SU (2) quasi-distributions on Poincare sphere. QPDF (Wigner function) of bi-modal quadrature coherent states is evaluated and numerically investigated to demonstrate the application.