| Optical microcavities typically have dimensions in the range of micrometers to nanometers,and use the total internal reflection of light to confine the light field in an extremely small cavity space.Through the effect of resonant feedback,the energy density of light inside the cavity is significantly increased,and the interaction between light and the material inside the cavity is enhanced.Through the discovery and exploration of researchers,the Whispering Gallery Mode(WGM)optical microcavity has been proposed,which has made important breakthroughs and rapid development in recent years.WGM optical microcavities have the characteristics of high quality factor,and are widely used in various fields such as high-sensitivity sensors,microcavity lasers,cavity quantum electrodynamics,and nonlinear optics.This thesis focuses on the research of optical microcavities based on the WGM and aims to finely control the intrinsic losses,mode distribution,and coupling states of the microcavity.Ultimately,high stability,high performance,and practical optical microcavity devices were achieved.The main research content and innovative work of this thesis are as follows:(1)The fine control of optical microcavity losses was studied.By improving the microcavity processing platform,the accuracy of microcavity processing has been enhanced.The intrinsic losses of microcavities mainly include radiation losses,scattering losses,and absorption losses.By optimizing parameters such as fusion carving point space and annealing time during microcavity processing,precise control of microcavity thickness and surface smoothness has been achieved,significantly reducing radiation and scattering losses of the microcavity.By selecting high-purity quartz rods with lower hydrogen and oxygen ion content,the material absorption losses of the microcavity were reduced,increasing the microcavity Q-factor to 10~9 and successfully producing microcavities with ultra-high Q-factors.(2)The fine control of optical microcavity modes was studied.The field intensity distribution of high-order radial modes in microcavities is mainly concentrated near the top position of the equatorial plane of the microcavity.Based on the electric field distribution characteristics of the modes,three methods were proposed,including changing the coupling efficiency between the microrod cavity and the tapered optical fiber,changing the curvature radius of the top of the microcavity,and the introduction of defects on the surface of the microcavity.The processing parameters and preparation process were optimized to control the number of excited modes in the microcavity to be less than 5 and to achieve a Q value greater than 1×10~8,successfully producing a few-mode,high-Q microcavity.(3)The fine control of optical microcavity stability was studied.The stability of microcavity packaging devices is related to the thermal expansion coefficient of the materials,the linear shrinkage rate of the adhesive,and the device temperature.By optimizing the materials,adhesive,and temperature control scheme,the stability of microcavity packaging devices has been improved,including temperature stability,mode excitation state stability,coupling state stability,and Q-value stability,and a smooth spectral envelope dissipative Kerr soliton was generated based on the microcavity packaging device,achieving high-performance,high-stability,and practical microcavity device packaging. |
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