Oscillation Phenomena And Coupled-resonator-induced Transparency And Absorption In Sausage-like Microresonators

Optical modes supported by Whispering-gallery-mode(WGM)microresonator have the characteristics of high quality factor and small optical volume,which make WGM microresonators become the important platforms for enhancing the interaction between light and matter.With further research on WGM optical microresonator,more and more applications have been realized in the field of sensing,micro-laser,nonlinear optics and so on.The sausage-like microresonator studied in this thesis is a kind of WGM optical microresonator.Which was proposed in 2015.And it is easy to change the resonant wavelength of its optical mode by stretching.In this thesis,the obtained results about the sausage-like microresonator include the following three parts:Firstly,the mechanical vibration in the sausage-like microresonator is studied in this thesis.When light is trapped in a sausage-like microresonator,the light pressure will cause the deformation of the sausage-like microresonator,which will produce mechanical vibration.Once the sausage-like microresonator is prepared,its natural vibration frequency has been determined,however,it may be necessary to tune the vibration frequency in some applications.This thesis studies how to observe the mechanical vibration in sausage-like microresonator and the influence of input light intensity on mechanical vibration.It also studies how to tune the frequency of mechanical vibration by simply stretching the sausage-like microresonator and using the effect of light spring.These contents are detailed in Chapter 2 and Chapter 3 of this thesis.Secondly,thermal oscillation behavior in sausage-like microresonator is studied in this thesis.When a sausage-like microresonator traps light,it can absorb very little of the light that can change the refractive index of the microresonator material and produce thermal effects,so that it is possible to observe thermal oscillations.In this paper,the thermal oscillation behavior of sausage-like microresonator is studied under the conditions of constant input laser wavelength and sweeping frequency.When the input laser wavelength is constant and its power is relatively low,the shape of the thermal oscillation transmission is not significantly different from that of the mechanical vibration transmission,but the frequency of the thermal oscillation is much smaller than that of the mechanical vibration.With the increase of input laser power,the shape of thermal oscillation transmission changes very differently from that of mechanical vibration transmission.Interesting phenomena such as ringing have been observed in the thermal oscillation when the input laser is in the frequency sweeping condition.These contents are detailed in Chapter 4 of this paper.Finally,coupled-resonator-induced transparency(CRIT)and coupled-resonator-induced absorption(CRIA)phenomena are studied theoretically and experimentally.The conditions for the occurrence of CRIT phenomenon and CIRA phenomenon,as well as the conditions for the transition between the two phenomena are analyzed theoretically.The prerequisite for the realization of these two phenomena is that the optical modes of the two microresonators have the same resonance frequency.In our experiment,the resonant frequency of the optical mode of the sausage-like microresonator was adjusted by stretching,which can make it be very close to the resonant frequency of the optical mode of the spherical cavity.Then,the transition between the CRIT phenomenon and the CIRA phenomenon was realized by controlling the coupling strength between the two microresonators.The theoretical fit was in good agreement with the experimental results.