An Optical Clock Based On The Topological Attractors In Polariton Bose-Einstein Condensates

Exciton polaritons in semiconductor microcavity are remarkable bosonic opoelectronic quasiparticles,suitable for the study of degenerate bosonic states at a few Kelvin or even at room temperature.The combination of the photonic component with its extremely small effective mass,and strong interparticle interactions mediated by the excitonic component,makes it possible to directly investigate numerous phenomena of fundamental interest,including superfluidity or topological defects.It opens up the prospect for developing a new nonlinear optical device in solid materials with great potential for controllability.Polaritons behave like photons but experience a strong nonlinearity.The phenomenon of superfluidity is characteristic of quantum fluids of light composed of polaritons.Polariton-polariton interaction is responsible for the light nonlinearity of cavity medium.On top of these properties,we expand our research around the following two aspects: firstly,we observe the topological excitation of vortices with stability in C-shaped polariton condensate and further generate the topological attractor with periodically oscillation;secondly,we explore the research of topological attractors in the possible application of optical clock with low pump power and micro-nano size.In this work,we propose a new scheme of topological attractors possible for the application of the optical clock with low pump power and micro-nano size.We examine the nonlinear dynamics of a circular polariton superfluid in the semiconductor microcavity containing a C-shaped external potential,which is pumped nonresonantly with a super-Gaussian light beam.We find two types of topological excitation with stability such as dipole mode of dark soliton and vortex as well as a periodical oscillation named as topological attractor.Here the topological attractor corresponds to the periodical rotation of the several Josephson vortices around the edge of the central vortex density.The attractors are topologically protected: perturbations have no effects on the oscillating dynamics in time.The system appears remarkably stability.Therefore,it is reasonable to believe that the system could be applied to the application of optical clock with low pump power and micro-nano size.We find that the clock can be continuously modulated over two different frequency ranges(20.16±0.14 GHz and 48.4±1.2GHz)by adjusting the intensity of the pump field.In addition,due to the chirality of the vortex,the clock studied in this work presents two degenerate rotation modes: clockwise and counterclockwise.By introducing a new incoherently controlled laser,the optical clock can switch to each other between these two degenerate rotation modes at will.Our work enriches the research of topological excitaiton and nonlinear science,promotes the application of semiconductor microcavity devices in the field of optical clocks,and provides a feasible technical choice for the development of solid-state information field.The research of the polariton optical clock is still in its infancy compared to the optical atomic clocks which have been studied for many years.Our scheme,however,has incomparable advantages over other systems such as micro-nano scale,room temperature operation,low pump power and micro-nano size.We believe that in future the semiconductor microcavity devices would be an ideal platform for the quantum information and possible applications such as optical clock.