Study On Optical Properties And Mass Sensing Based On A Nanomechanical Resonator System

In recent years,the coupling between optical degree of freedom and mechanical degree of freedom has been attracting the attention of researchers.Therefore,the optomechanical system has always been a research hotspot.With the development of nanometer science and technology,the size of mechanical resonators has been reduced to nanometer level,and a variety of resonators have been generated,which provides a good platform for the study of quantum optical properties of nanomechanical systems.In general,a nanomechanical vibrator has very small mass and volume,low dissipation and high-quality factor and resonance frequency.Therefore,nanomechanical vibrators have very important application value in high-precision gravitational wave detection,displacement measurement,mass sensing and so on.In this paper,we mainly study three systems in the field,namely quantum dot-nanomechanical oscillator coupling system,spin-nanomechanical coupling system and nitrogen-vacancy center-photonic crystal coupling system.This paper is divided into five chapters.The first chapter is the introduction.Firstly,we introduce the nanomechanical system,quantum dot and nitrogen-vacancy center.Then,we introduce the optical polarizability and mass sensing principle,as well as the optical pump-probe technology used.In the second chapter,we study the coherent optical properties of the quantum dot-nanomechanical system.By.analyzing the detection absorption spectrum of the system,the effect of mode splitting is found,and the distance between the two spikes is proportional to the coupling strength,the method to determine the coupling strength of the system is given.In addition,we can accurately measure the vibration frequency of the mechanical vibrator.Finally,an all-optical mass sensing scheme at room temperature is proposed because the nanoparticles attached to the nanomechanical oscillator will cause the resonance shift of the absorption spectrum of the system.In the third chapter,we propose a spin-nanomechanical resonator coupling system for nonlinear mass sensing at room temperature using pump probe technology and NV color center spin readout technology.The system consists of an nitrogen-vacancy center and a nanomechanical cantilever.The resonance frequency of nanomechanical oscillators can be used to study the nonlinear Kerr effect and its influencing factors.In addition,according to the relationship between the frequency shift of the peak in the absorption spectrum and the mass change caused by the addition on the nanomechanical resonator,the system can use the nonlinear Kerr spectrum at room temperature to detect the mass of DNA molecules.In the chapter 4,we propose a cavity quantum electrodynamic system consisting of a nitrogen-vacancy center(NV)and a photonic crystal nanocavity,and investigate the interactions between light and matter in the hybrid system under weak coupling,intermediate coupling and strong coupling conditions.The results show that under different parameters,by controlling the coupling strength of the system,the change of the vacuum Rabi splitting spectrum line is shown in the absorption process.The fifth chapter is summary and prospect.Figure[17]reference[129].