arXiv subjects

Kapil Debnath

Publications and source records attributed to Kapil Debnath.

6 recordsLinked to original sources

arXiv2024

All optical chaos synchronization between nonidentical optomechanical cavities

Optomechanical cavities, with nonlinear photon-phonon interactions, offer a more compact approach to chaos generation than conventional feedback-based optical systems. However, proper study on chaos synchronization of two optomechanical cavities connected by optical means is still unexplored. In this work, we theoretically investigate all-optical complete synchronization between unidirectionally coupled optomechanical cavities in the master-slave configuration. Traditionally, achieving complete synchronization in nonlinear coupled oscillators and in optical systems necessitates identical systems. Our findings, which arise naturally from the fundamental mathematical properties of optomechanical cavities, demonstrate that parameter heterogeneity can, in fact, not only enable complete synchronization but make it stable.

physics.optics↗

arXiv2024

Inverse Opal Optical Tamm State for Sensing Applications

We report the existence of optical Tamm states (OTS) in inverse opal (IO) - based three-dimensional photonic crystal on a flat metal substrate, validated through both numerical simulations and experimental observations. Our fabrication approach for the Tamm inverse opal (Tamm-IO) structure is notably straightforward and does not involve corrosive chemicals. Upon infiltration of non-reactive solvents such as methanol and ethanol into the IO, a noticeable shift of the OTS, consistent with our simulations is observed, and the temporal dynamics of the same have been investigated. The experimentally obtained sensitivity is ~ 110 nm/RIU which is of the same order as the computed value, making the IO OTS to be an attractive sensing tool.

physics.optics↗

arXiv2024

Cauchy-Schwarz and Bell Inequality Violations in Coupled Optomechanical Systems

Destructive interference-based photon-phonon antibunching can lead to violations of classical inequalities in optomechanical cavity systems. In this paper, we explore the violation of the classical Cauchy-Schwarz inequality by examining second-order auto-correlation and cross-correlation functions, as well as Bell's nonlocality, to analyze the quantum correlations of single photon-phonon excitations when the system is driven by two weak probe fields. We propose that the violation of the Cauchy-Schwarz inequality can serve as an indicator for the stronger nonclassical tests associated with Bell's theorem. Our system reveals strong quantum correlations of photon-phonon pairs with distinctive antidiagonal patterns of photon filtering. For numerical analysis, we consider a weak effective optomechanical coupling strength and various optical-to-mechanical field amplitude ratios that enable unconventional photon (phonon) blockades at resonance. The findings are significant for producing sub-Poissonian signals under optimal conditions and have potential applications in hybrid systems for generating on-demand single photon-phonon pairs.

quant-ph↗

arXiv2024

Chaotic dynamics under the influence of synthetic magnetic field in optomechanical system

The optomechanical systems produce chaotic behaviour due to nonlinear interaction between photons and phonons, and the same systems are used to understand the synthetic fields as well. Here, we report on the study of chaotic behaviour in the presence of a phononic synthetic magnetic field in a closed loop configuration consisting of a single optical mode and two mechanical modes. The modulation phase of the mechanical coupling between the two mechanical modes plays a critical role in determining the mechanical and optical intensity dynamics in the nonlinear regime. Our study shows the dark mode breaking effect in the presence of a synthetic magnetic field, which brings about a complex way of mechanical energy exchange that causes the cavity field to alternate between chaotic and regular behaviour periodically in temporal domain. However in the stronger nonlinear regime the temporal dynamics demonstrate predominantly chaotic behaviour. Besides, with the advent of advanced fabrication technologies, this study holds promises in developing phase tunable integrated low-power chaotic light sources to support efficient optical secure communication systems.

physics.optics↗

arXiv2023

Controllable optical sideband generation by breaking mechanical Parity-Time symmetry

The interaction between light and mechanical vibrations in a cavity is often exploited to produce higher order sidebands (HOS) /combs, which are used in optical communication networks, spectroscopy, and others. Although a considerable study of optomechanically induced HOS has been done, its proper control and manipulation using only continuous wave (CW) laser drive are still to be explored. Here, we employed mechanical Parity-Time (PT) Symmetric structure with optically induced gain and loss. It has allowed us to manipulate the flow of mechanical energies (phonons) between the cavities, which has consequences on the optical response of the cavities. Based on our numerical investigations, we found that the higher order optical sidebands start to emerge by breaking PT symmetry. We precisely controlled the number of higher order sideband lines by adjusting the coupling rate between the cavities with fixed drive power. In addition, we observe that the Exceptional Point (EP) induces the formation of two synchronized higher order optical sideband spectra, which opens a promising EP based platform towards realization of optical readout of various mechanical synchronization phenomena, memory applications, sensing, synchronization of remote clock time and others.

physics.optics↗

arXiv2012

Highly efficient optical filter based on vertically coupled Photonic crystal cavity and bus waveguide

We experimentally demonstrate a new optical filter design based on a vertically coupled photonic crystal cavity and a bus waveguide monolithically integrated on the silicon on insulator platform. The use of a vertically coupled waveguide gives flexibility in the choice of the waveguide material and dimensions, dramatically lowering the insertion loss while achieving very high coupling efficiencies to wavelength scale resonators

physics.optics↗