ABSTRACT
Hard X-ray Fabry-Perot resonators (FPRs) made from sapphire crystals were constructed and characterized. The FPRs consisted of two crystal plates, part of a monolithic crystal structure of Al2O3, acting as a pair of mirrors, for the backward reflection (0â 0â 0â 30) of hard X-rays at 14.3147â keV. The dimensional accuracy during manufacturing and the defect density in the crystal in relation to the resonance efficiency of sapphire FPRs were analyzed from a theoretical standpoint based on X-ray cavity resonance and measurements using scanning electron microscopic and X-ray topographic techniques for crystal defects. Well defined resonance spectra of sapphire FPRs were successfully obtained, and were comparable with the theoretical predictions.
ABSTRACT
Electro-optical tuning of a microring resonator fabricated on lithium niobate (LiNbO3) is presented. The device structure, including microring resonator and couplers, is designed in detail and is produced by titanium diffusion on the wet-etched LiNbO3 ridge surface. The resonance wavelengths for TM and TE polarizations can be tuned by electro-optic effect. The output characteristics of through port and drop port in the microring resonators are measured, and the effect of applied voltage on the shift of resonant wavelength is discussed. The presented microring resonators have the features of fast tuning speed, high material stability, bidirection wavelength shift, and no heating interference. Realization of such a microring resonator on LiNbO3 makes the utilization of electro-optic tuning and nonlinear effects in the versatile photonic applications of microring resonators achievable.
