Fabrication And Characteristics Test Of High-Q Planar Microcavities

Ultra-high quality factor optical micro-resonators with Whispering Gallery Mode (WGM) and small mode volume become powerful tools to explore non-linear optics and cavity quantum electrodynamics(CQED). There are also potential applications in optical integration, optical network, optical quantum entanglement computing and other information field. The main optical micro-resonators include microspheres, pillar microcavities and the planar microcavities (planar microdisks and planar microtoroids). This paper will focus on the study of planar microcavities. Using the MEMS processing technology, we have designed and fabricated high-Q value planar microcavities. Then we build a coupling system and test the quality factors. The main contents and key points of this thesis are as follows:1. Choose silica material to fabricate the planar microcavities. Firstly 2-micron thick SiO2 layer was thermally grown on (100) silicon crystal surface, and then photoresist painting, exposure, and a variety of etching; For etching the silica dioxide layer we use wet etching(HF/H2O solution) and dry etching (reactive ion beam etching) respectively; For etching silicon column we use ICP etching system and XeF2 etching system. Secondly use lithography and etching methods to produce planar microdisks, this fabrication is a multi-step process, each step should be very precise in order to ensure the high-Q values, especially in the silicon discerption process as the mushroom-shaped microstructures are more easily washed out. Therefore, during the fabrication process, we explore a new and viable technique of optical planar microcavities machining line.2. Use existing platforms and Diamond K-500 CO2 pulsed Laser in our optical laboratory and build the planar microdisk surface heat treatment processing system by ourselves; In the experiment, try to design dual-optical system, small hole filter system and turning flat system to complete the process.3. In our experiment we have used RS3100 nano-fiber taper drawing machine to gain nano-fiber taper with 1μm -2μm for coupling test. 4. Build the coupling system. Firstly with brief description of coupled systems theory and the effects analysis of the system Q value, we get three major coupling states during the coupling operating: undercoupling, critical-coupling, and over-coupling; Secondly use the coupling system to test planar microdisks and planar microtoroids, and obtain their Q values are 3.2×105 and 1.6×105 respectively.