Fabrication And Applications Of High-Q Silica Optical Microdisk Resonators On A Chip

Optical microcavities are fundamental photonics micro-nano devices which can confine light with specific frequency to small volumes.Among them,whispering gallery mode(WGM)silica optical microresonators,owing to their high quality factors and small mode volumes,have been widely used in optical communication,nonlinear optics,biological sensing,cavity optomechanics and cavity quantum electrodynamics.This thesis mainly focuses on two different types of silica optical microdisk resonators and their applications.First,we describe the fabrication of on-chip high-Q silica microdisk optical resonators with large wedge angles and their applications in nonlinear optics.By reactive ion etching,we have achieved wedge angles of 59°,63°,70°,and 79° with optical quality factors of 2.4×107,8.1×106,5.9×106,and 7.4×106,respectively,from?80-?m-diameter and 2-?m-thick microresonators.Based on the microdisk with a wedge angle of 59°,we observe the Raman laser with a threshold of 1.3 mW in the 1550 nm wavelength band.Also,for 1-?m-thick microresonators,we have obtained optical quality factor of 7.3×106 with a wedge angle of 74°.In the measurement process,we provide a new and efficient way to find out the fundamental modes of the silica microdisk cavities.This kind of silica microdisk resonator with a large wedge angle will enable monolithic integration of the microdisk resonator coupled to a waveguide or another microdisk cavity.Also,using HF etching we fabricate the silica microdisk resonators with small wedge angles whose optical quality factors can be achieved to 107.We then demonstrate the mechanical regenerative oscillation of this microdisk resonator in air and vacuum,respectively.Second,we introduce the fabrication of the high-Q silica double-wheel microdisk cavities and their applications in the electromagnetically induced transparency(EIT)-like effect.The double-wheel microcavity consists a pair of coupled microrings,which can produce a large optical gradient force.We measure the modulation of the resonant wavelength by the optical gradient force in the double-wheel microcavity which has a tuning efficiency of?1.6 nm/mW.We also observe the optical spring effect and the regenerative oscillation of the mechanical mode.Besides,based on the coupling system between silica double-wheel and microtoroid cavities,we demonstrate an all-optical analog of EIT.In the experiment,to match the resonant modes of the two coupled microcavities,we shift the resonant wavelength of the double-wheel microcavity by 1.5 nm via the optical gradient force.A typical EIT-like spectrum is finally obtained with a transparency of 93%and a spectral width of the transparency window as narrow as 82 MHz.Moreover,we can precisely tune the EIT-like spectra by independently controlling the frequency detuning and the coupling rate between the two cavity modes.