INTERMODAL ENTANGLEMENT IN THREE-MODE OPTOMECHANICS

We explore the possibility of intermodal entanglement between two optical modes and a mechanical mode for three-mode optomechanics. The Hamiltonian of the system is solved analytically, using Heisenberg-Langevin equation and also Taylor’s series expansion of an operator. Temporal variation of entanglement parameter corresponds to different field modes are studied under different weight factor of initial state and dependence on interaction strength is also reported. Entangled state at macroscopic level is observed

Higher order two-mode and multi-mode entanglement in Raman processes

The existence of higher order entanglement in the stimulated and spontaneous Raman processes is established using the perturbative solutions of the Heisenberg equations of motion for various field modes that are obtained using the Sen-Mandal technique and a fully quantum mechanical Hamiltonian that describes the stimulated and spontaneous Raman processes. Specifically, the perturbative Sen-Mandal solutions are exploited here to show the signature of the higher order two-mode and multi-mode entanglement. In some special cases, we have also observed higher order entanglement in the partially spontaneous Raman processes. Further, it is shown that the depth of the nonclassicality indicators (parameters) can be manipulated by the specific choice of coupling constants, and it is observed that the depth of nonclassicality parameters increases with the order.Comment: 9 pages, 5 figures. arXiv admin note: text overlap with arXiv:1301.028

Optically induced transparency in coupled micro-cavities: tunable Fano resonance

We theoretically investigate the phenomena of optically induced transparency for a weak probe field and tunable asymmetric Fano line shape in coupled micro-cavities. One of the cavities is passive, consists of optical Kerr medium and coupled via photon tunnelling to an active cavity. The forward transmission and backward reflection profile of the output fields are analyzed for both passive-passive and passive-active cavity system by varying different system parameters. The transmission spectra show tunable transparency window and sharp asymmetric Fano line shape structure. The sharpness of line shape profile is controlled via the gain-to-loss ratio, photon tunnelling strength, Kerr nonlinear strength and input power. The findings in this study have the potential to be used as a highly sensitive sensor and also useful for telecom system

Unconventional magnon blockade in a superconducting qubit coupled magnomechanical system

In this study we theoretically and numerically analyze the magnon statistics properties of a weakly driven qubit–magnon–phonon system consisting of a magnon mode in a ferromagnetic yttrium iron garnet (YIG) coupled to a transmontype superconducting qubit and also to the mechanical mode of vibration of the YIG sphere. We analytically determine the optimal magnon detuning required for occurrence of magnon blockade in weak Kerr nonlinear regime. We also numerically evaluate the second order magnon correlation function and plot it against different system parameters to find that the numerical results are in agreement with analytical optimal conditions. we study the dependence of magnon statistics (second-order correlation function) on different system parameters (magnon–phonon coupling strength, magnon detuning and Kerr nonlinearity) in a weakly driven qubit coupled magnomechanical system consisting of a suerconducting qubit, a magnon mode and a mechanical modes where the magnon mode is coupled with both the qubit and mechanical modes. The system exhibits unconventional blockade (i.e at weak nonlinearity), with the value of second-order correlation function in the range of $$10\,\hat{}{-3}$$–$$10\,\hat{}{-2}$$ indicating very strong magnon antibunching

Tunable induced transparency and Fano-resonance in double cavity optomechanical system

We analyze optomechanically induced Transparency and asymmetric Fano-line shape Profile in a two-mode cavity system, coupling at weak and strong coupling regimes. The model system consists of one mechanical mode and two optical modes. The transmission shows nonreciprocal behavior. Both the forward transmission and backward reflection for the system are analyzed for both optic-optic and mechanical-optic cavities by considering various system parameters. The output spectra lead to sharp asymmetric Fano-resonance and tunable transparency. Double line-shape profile is observed in the output Spectrum. Our proposal provides a new platform for application in quantum telecommunications and a photonic device like optical Switches

Safety and Toxicity Counts of Nanocosmetics

The advent of nanotechnology has led to advances in the cosmetic industry and is expected to grow further in the near future. Nanotechnology-driven products cater to the expectations of both consumers and manufactures in terms of better quality and effectiveness along with improved stability and easy scale-up. Several organic and inorganic materials are being utilized for the preparation of nanocosmetics having improved characteristics. At the same time, the safety aspects of nanocosmetics are also being pondered. Physicochemical properties play a significant role in controlling the toxicity of nanomaterials. Several mechanisms have been studied for nanomaterial generated toxicity; out of all, reactive oxygen species, generation is the most important mechanism. This chapter discusses all the relevant aspects which are required for safety and toxicity assessments of nano-ingredients for cosmetic use. Regulatory issues are also discussed because of their relevance in preventing the unforeseen toxicity of nanocosmetics