Time-harmonic Weak Force Induced Sum And Difference Sidebands And Their Sensing In Cavity Optomechanical Syste

In recent years,the subject of force sensors has attracted considerable attention in scientific and technological communities due to its indispensable practical value and possible applications in biomedicine and aerospace engineering.As a fundamental quantity in physics,force has higher and higher requirements for its sensitivity and precision in many research fields.With the continuous development of force sensing technology,the design and preparation of high-performance sensing devices has become a research hotspot in the field of science and technology,and also has certain theoretical and practical significance.Recent research shows that the cavity optomechanical system can be used as an ideal platform for precise measurement due to its unique physical properties including small inertia mass,the broad range of resonant frequency and low dissipation.Cavity optomechanical systems,which use radiation pressure as a medium to couple the optical mode and mechanical mode of the system,affecting the optical field distribution and the dynamic characteristics of mechanical vibration.Among them,the mechanical characteristics of radiation pressure also make the optomechanical system more likely to become the carrier of ultra-sensitive force sensing.Generally,the results achieved in cavity optomechanics are based on linearized optical phenomena,such as normal-mode splitting,optomechanically induced transparency,and optical non-reciprocity.However,many non-classical states and parametric conversion can only be realized by nonlinearities in cavity optomechanical systems.Since nonlinear optomechanical coupling is far weaker than linear optomechanical coupling,enhancing nonlinear optomechanical interaction has become a research frontier in cavity optomechanics.The purpose of this thesis is to apply the nonlinear effect of cavity optical force system to the field of high-performance mechanical sensing;The output efficiency of the neutral-difference sideband spectrum and the quantum coherence control of the sideband spectrum in different cavity optical force systems are studied in detail;After extracting the relevant information between the physical properties of the mechanical oscillator and the nonlinear sideband spectrum in the system,a scheme for sensing the time-harmonic force is designed.It mainly includes the following three parts:The first part includes the introduction and theoretical basis,mainly introducing the working principle and application of optomechanical system,the physical mechanism of optomechanical induced transparency and the theoretical tools needed for calculation:perturbation theory and input-output theory.In the second part,we propose a time-harmonic force sensing scheme in a hybrid optomechanical system for the first time by using the mechanism of force-induced parameter conversion and sideband signal amplification.Based on Heisenberg-Langevin equations,we give analytical expressions for linear transmission spectra and sideband spectra.Under the support of the two correlations between the frequency spectrum and the time-harmonic force,it is found that the amplitude and frequency of the time-harmonic force can be measured separately by monitoring the intensity variation and the frequency of the prominent peak in the lower sum sidebands.When the optical cooling technology is used to cool the optomechanical cavity with sideband resolution,we also report that the mechanical oscillator is cooled to 10^-3K.In this optomechanical environment,the minimum resolution for detecting the amplitude and frequency of time-harmonic force is:8.8×10^{-1 2}Nand 16Hz.In the third part,the vector time-harmonic force sensing is realized in the two-mode optomechanical system by using the vector force to induce the generation of two-color difference sidebands.Also using the theoretical method of quantum optics,the project obtains an accurate expression of the difference band spectrum in the two dimensions of x-y.Since the two mechanical modes of the system are different,both horizontally and vertically,the output spectrum appears as two difference signals,the two-color sideband.When mechanical elements in both dimensions are associated with vector forces,the system can be designed as a sensing device for vector forces.When using advanced thin film manufacturing and optical microcavity experimental data,the detection sensitivity and resolution of the dual-parameter sensor are analyzed in this paper.Additionally,the detection sensitivity of vector force for amplitude and frequency is 6.5×10⁵ N^-1 and 1 Hz/Hz,respectively.The resolution of its amplitude and frequency can be estimated at 1.3×10^-17 N and 1 Hz.In conclusion,the study of time-harmonic force induced sum and difference sidebands in this paper has certain theoretical research value for nonlinear parametric conversion and multi-parameter sensing applications.