Refractive Index Sensor Based on an Optical Microresonator Using a Hollow Sphere with Porous Wall

摘要

An optical microresonator based upon a hollow sphere with a porous wall has been proposed for use as a refractive index sensor. The sensor structure was created by coupling a Porous Wall Hollow Glass Microsphere (PW-HGM) to a single mode fiber taper (Corning SMF-28). The experimental results showed that the PW-HGM can be effectively stimulated by evanescent waves propagating through a single mode fiber taper when the coupling modes match. The Quality-factor (Q-factor) and Free Spectral Range (FSR) were measured for a variety of PW-HGMs ranging in size from lOum to lOOum in diameter. When the microresonator system was tested in a vapor sample, the resonant wavelengths of the microresonator system drifted with respect to the change in refractive index. After discussing the experimental, this microresonator sensing method, which employs porous microspheres instead of solid spheres, demonstrates noteworthy progress in excitation efficiency when compared with other methods. In addition, this system demonstrates effective excitation of high-sensitivity microcavity resonances.