| In recent years,with the continuous development of the laser technologies and the continuous maturity of the micro-fabrication technologies,the cavity optomechanical system composed of optical microcavity and mechanical oscillator has made remarkable achievements and breakthroughs in experiments.Furthermore,with the profound development of the research on cavity optomechanical system,it is found that it has exhibited some unique application advantages in some studies,such as quantum information processing,photonic devices,precision measurement,new laser and so on.Therefore,the cavity optomechanical system has attracted much attention both in theoretical and experimental.In this thesis for the Doctorate,by using the basic knowledge of cavity quantum electrodynamics(CQED),we have mainly studied the optical nonlinearity in hybrid cavity optomechanical systems and proposed an efficient scheme for realizing ultrasensitive charge detection sensor by exploiting the optical second-order sidebands of the hybrid cavity optomechanical system.In addition,we have also studied the localized-surface plasmon resonances(LSPRs)of the metallic nanoparticles(MNP)in a microcavity system and proposed two different efficient schemes for detecting the radius of MNP.The main contents are as follows:1)We propose and analyze a scheme to realize the enhancement of the generation efficiency of the optical second-order sidebands(OSS)by using the gain cavity in the optoelectronic hybrid cavity optomechanical system(GCAOM).At the same time,by using the dependence of Coulomb interaction between charged oscillator and charged body on the maximum generation efficiency of the optical second-order sidebands,we propose an efficient scheme for realizing ultrasensitive charge detection sensor.The system is composed of a gain cavity and a classical cavity optomechanical system.The oscillator of the classical cavity optomechanical system is charged,which coupled with the charged body through the Coulomb interaction.It is shown that an assisted gain cavity can significantly enhance the OSS generation and can also lead to higher charge dependence of the output OSS spectrum than that achieved from a lossy cavity optomechanical system.Subsequently,we discuss the application of such a GCAOM system as a family of high-sensitivity sensor for measuring the charges.Using experimentally achievable parameters,we identify the conditions under which the assisted gain cavity allows us to enhance the OSS generation and improve sensitivity of the sensor beyond what is achievable in a lossy cavity optomechanical system.It is found that the highest sensitivity for measuring the charges could be improved with more than four orders of magnitude in the presence of the assisted gain cavity than that in the absence of the assisted gain cavity.The present investigations may lead to better understanding of the crossover between nonlinear spectroscopy and Coulomb interaction in hybrid electro-optomechanical systems.2)We propose a potentially practical scheme for realizing ultrasensitive size sensor of a single metallic nanoparticles(MNP)in a hybrid nonlinear microcavity.This is achieved by exploiting a well-established microcavity-engineered plasmonic resonance,where a degenerate parametric amplifier(DPA)is embedded into the microcavity driven by a strong pump field and a weak probe pulse.It is shown that due to the presence of the DPA,the transmission spectrum of the probe pulse exhibits a two-peak splitting and the splitting width depends on the radius of the MNP.The radius of a single MNP can be inferred from the transmission spectrum by monitoring the width between two peaks.Using experimentally achievable parameters,we demonstrate that the detection sensitivity of the sensor can reach approximately 0.198THz/nm for detecting and sizing of individual MNPs as small as 10 nm in radius using DPA induced spectral splitting even with low quality factor of the optical microcavity.More importantly,with the help of DPA,we find that the noise squeezing spectrum is lower than the standard quantum limit.Compared with other schemes based on microcavity system to detect the radius of single nanoparticles,the requirement of optical microcavity in our proposed scheme is not high,the quality factor is only 2500,and it is easier to realize in experiment.3)Based on an adjustable electromagnetic environment provided by microcavity,we propose and analyze another efficient way to investigate the relationship between linewidth and radius of the metal nanoparticle(MNP)in a hybrid optical microcavity system.In the system,the coupled quantum emitter and metallic nanoparticle are placed in an optical microcavity.By using detailed numerical simulations and analytical modeling,we find that the linewidth of the amplification window is sensitive to the radius of MNP.Subsequently,we discuss the application of such a hybrid optical microcavity system as a family of high-sensitivity sensor for measuring the tiny radius of the MNP.Using experimentally achievable parameters,we identify that the detection sensitivity of the sensor can arrive at approximately 2.6 GHz/nm.Compared with other works,the advantages of our system are as follows: firstly,the quality factor of the cavity is much lower than other works.As we know,in the previous single nanoparticle detection work,they usually required a cavity with a high quality factor.However,in the current material processing technology,obtaining a high-quality optical microcavity is still a problem.Secondly,we choose the linewidth as the observation measure to detect the radius of MNP.Because the mode broadening sensing mechanism is not only insensitive to the laser frequency noise and thermal fluctuations,but also discards the requirement of an ultra-high Q needed to resolve the doublet in the spectrum.In conclusion,this thesis deepens our awareness and understanding of the characteristics of nonlinear optics in hybrid cavity optomechanical system.Moreover,this thesis deepens our awareness of the value of the application of the hybrid cavity optomechanical system.These investigations may have some reference value for the developments of the nonlinear spectroscopy,precision measurement and cavity optomechanics. |
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