| Summary: | 碩士 === 國立臺北科技大學 === 光電工程系 === 106 === Tantalum pentoxide has advantages of high thermal stability, high chemical stability, high refractive index, high dielectric constant, and low optical loss, and has been widely applied in fabricating optical components. In this thesis, the tantalum pentoxide film is deposited on the silicon substrate by radio-frequency magnetron sputtering. Its material and optical properties are analyzer by atomic force microscope, X-ray diffraction, and ellipsometer. The undercut tantalum pentoxide microdisk resonators with 40μm diameter have been successfully fabricated by using photolithography, film deposition, and lift off, and wet etching. The measured intrinsic quality factor is up to 1.645×104 and the free spectral range (FSR) is 11.5nm. When the device temperature raises, the resonance wavelength is red-shifted and its thermo-optic modulation rate was 7.2 pm/°C. Quantum dots are a kind of semiconductor material with nanostructure and have the advantages of narrow full width at half maximum (FWHM), wavelength adjustability, high radiation efficiency, and good luminescent stability. In this thesis, the quantum dots thin film deposited on tantalum pentoxide microdisk resonators are used as gain medium. In the experiments, perovskite quantum dots in the toluene solution are successfully synthesized and are doped in the PMMA for the formation of thin film. The emission wavelength of perovskite quantum dots in the toluene solution and the perovskite quantum dots incorporated PMMA films is in the range from 520.9nm to 520.8nm. Their PL center wavelengths are 520.9nm and 520.8nm, respectively. The fabricated devices have the three layer structure of (tantalum pentoxide)/(perovskite quantum dots incorporated PMMA thin film)/(tantalum pentoxide). The SU-8 negative resistance has the advantages of good etching resistance, good thermal stability, and small optical absorption. Even though using the thick SU-8 film, the films have good uniformity and vertical sidewalls. In the thesis, the undercut 40μm diameter SU-8 microdisk resonators have been successfully fabricated. Their intrinsic quality factor is up to 1.098×104 and the FSR was 12.3nm. The SU-8 microdisk devices have the advantages of high quality factor, easy fabricated process, and low fabrication cost. They have the potential used as quantum dots incorporated main structure for the application of micro laser.
In the research of waveguide coupled lithium niobate microdisk resonators, the structure of titanium diffusion waveguide coupled microdisk resonator is designed. The amount of optical field coupling to microdisk is promoted by tuning the depth position between the microdisk resonator and the titanium diffusion waveguide. In experiments, the 60μm diameter LiNbO3 microdisk resonators are fabricated with two kinds of microdisk depth (0μm and 2μm) and three kinds of distance between microdisk and waveguide (1μm, 0μm, and -1μm). The measurement results show that the optical field resonance in the microdisk resonator occurs only when the microdisk depth is 2μm, and the distance of microdisk embedded into waveguide is 1μm. The highest intrinsic quality factor is as high as 7.846×102 and the FSR is 6.7nm. The optical resonance phenomena of other waveguide-coupled microdisk resonators are not observed due to the less amounts of optical field coupling from the titanium-diffused waveguide.
|
|---|
