arXiv subjects

Gyaprasad

Publications and source records attributed to Gyaprasad.

3 recordsLinked to original sources

arXiv2026

Modulation in degree of cross-polarization at Young's interferometer illuminated by non-uniformly polarized electromagnetic fields

The degree of cross-polarization (DoCP) and the electromagnetic degree of coherence (EM DoC) of an electromagnetic beam are investigated at the observation points for incoherent and non-uniformly polarized, i.e., different degree of polarization with respect to space at the two pinholes in Young's interference experiment. We note that DoCP at the observation plane can be expressed as the average value of the degree of polarization at the pinholes of Young's interference experiment. The present study also verifies that the DoCP is a two-point generalization of the DoP. Additionally, EM DoC at observation points can be controlled by DoP at pinholes. The findings may be useful for classical ghost imaging, lensless imaging, and the study of Stokes correlations.

physics.optics↗

arXiv2026

Electro-optically controlled photon group velocity, temporal walk-off and two-photon entanglement via nematic liquid crystal

The propagation of the quantum states of light in dispersive and anisotropic media is a fundamental problem in quantum optics. We present a unified theoretical framework for the propagation of the quantum states of light in voltage-controlled nematic liquid crystals, incorporating both material dispersion and electrically tunable birefringence. By treating photons as finite-bandwidth wave packets, we derive analytical expressions for group velocoity, temporal walk-off, and phase evolution of orthogonally polarized modes. The results demonstrate that nematic liquid crystals can serve as electrically tunable quantum photonic devices capable of manipulating photon arrival times, polarization correlations, and temporal indistinguishability of entangled photon pairs. These results show the direct relevance to quantum communication and photonic quantum information processing.

physics.optics↗

arXiv2026

Real-time polarization tuning in Mach-Zehnder interferometer using electro-optically modulated twist angles of nematic liquid crystal Note: This paper has been accepted for publication in "Journal of Theoretical and Applied Physics"

We propose a theoretical framework to dynamically control the degree of polarization of light by using the superposition of incoherent orthogonally polarized beams in a Mach-Zehnder interferometer incorporating a twisted nematic liquid crystal cell in one of its arms. The liquid crystal acts as an elecro-optically controlled polarization rotator, where the applied electric field changes the twist of molecules inside the nematic liquid crystal, thereby altering the plane of polarization. This controllable voltage dependent polarization rotation causes manipulation of the output degree of polarization. The resulting system allows real-time, tunable control over the degree of polarization, offering advantages over traditional static or reflection-based approaches, which often suffer from intensity losses or manual errors. We also observe that in the interference of fully coherent orthogonally polarized beams through a similar configuration, the degree of polarization is always equal to 1, whereas the orientation of linear state of polarization is changed with voltage.

physics.optics↗