Studies On High-order Sidebands And Optical Transmission Characteristics In Cavity Quantum Systems

Photons have very important and wide use in information processing,acquisi-tion and control due to its great advantages in information transmission.After the advent of laser,optical communication has made breakthroughs and developed fast.Systems composed by optical cavities constraint light in small space so as to increase light intensity and enhance light-matter interactions.These systems can process in-formation transfer and conversion in single photon level and hence have huge advan-tages in optical device construction.In recent years,cavity quantum electrodynamic system and opto-mechanical system are simple but versatile optical platform,have important applications in quantum information and quantum networks.We discussed the nonlinear effects and related optical information transfer process in cavity QED and opto-mechanical systems.Includes:First,we put forward a plan for photon conversion and information processing through quantum dot and high-order sidebands.The Photonic Crystal(PC)cavity supports two cavity modes which are not coupled to each other due to their orthogo-nal polarizations.Only one the optical modes is coherently driven by the laser field.Through position arrangement,the quantum dot(QD)coupled to both optical modes.Under the driven of a two-tone continuous-wave laser field,the system possess strong third-order nonlinearity,in which Raman scattering and four-wave mixing occurs,re-sulting in higher-order sidebands generation.Then,the output spectrum of the system shows a spectra with a variety of equally spaced narrow sharp lines(optical comb).As a vehicle,Quantum dot transfers and converts information efficiently between the optical modes and QD.Thus,the optical mode without excition also has high-order sideband generation because the energy can flow from the the driven mode though the quantum dot.we explore the effect of optical high-order sideband generation and ef-ficient sideband information transfer between the two optical modes.The influences of the system parameters on optical high-order sidebands generation and transfer ef-ficiency are studied.We also discussed the physical explanation of the underlying mechanism and an experimental feasibility of the proposed bimodal cavity scheme.The system we built can engineer and convert photons between different frequen-cies in a solid-state approach,has extensive technological implications not only for classical communication systems,but also future integrated quantum networks.Second,we propose a plan for the enhancement of high-order sidebands which cooperates with the parity-time reversal(PT)symmetric theory.PT-symmetric con-cept was brought up initially in mathematics,and it perfects the quantum theory about the non-hermitian operator.PT-symmetric optical systems,which rely on the balanced gain-loss condition,have provided a new platform to engineer effective light-matter interactions in recent years.Here we explore the linear and nonlin-ear output characteristics of a PT-symmetric optical system consisting of a pas-sive nonlinear cavity coupled to an active linear cavity.The system possesses a phase transition from the PT-symmetric phase to the PT-broken phase when the photon-tunneling strength is adjusted to pass through the EP.By analytic formulas and numerical simulation,it is clearly shown that both the generation efficiency of the low-order sidebands and high-order sidebands can be greatly enhanced in the PT-symmetric dimer,extremely in the vicinity of the transition point from unbroken-to broken-PT regimes,compared with the passive-passive double-cavity system.All that is because the nonlinearity will be greatly improved when the system is in the vicinity of exception point(EP).We explained the underlying physical mechanism with theoretical derivation in detail.Our obtained results provide a new avenue for acquiring optical high-order sidebands and operating light,which may inspire further applications in chip-scale optical communications and optical frequency combs.Third,we propose a scheme to strengthen the non-reciprocal effect in opto-mechanical system.In this scenario,we built a system combined PT-symmetry and opto-mechanics and studied the light transmission effect.First,we got the scattering matrix of the system through theoretical derivation.Using available values we find that the optical transmission of the PT-symmetric composite system will be amplified.Moreover,we achieved more perfect one-way transmission effect and about 40 dB isolation value in theoretically.Our plan can be process under the existing technology,has important applications in the optical components production.