Automatic Alignment Method for Controlled Free-Space Excitation of Whispering-Gallery Resonances

Year: 2023

Authors: D’Ambrosio D., Capezzuto M., Giorgini A., Malara P., Avino S., Gagliardi G.,

Autors Affiliation: CNR-INO

Abstract: Whispering-gallery mode microresonators have gained wide popularity as experimental platforms for different applications, ranging from biosensing to nonlinear optics. Typically, the resonant modes of dielectric microresonators are stimulated via evanescent wave coupling, facilitated using tapered optical fibers or coupling prisms. However, this method poses serious shortcomings due to fabrication and access-related limitations, which could be elegantly overcome by implementing a free-space coupling approach; although additional alignment procedures are needed in this case. To address this issue, we have developed a new algorithm to excite the microresonator automatically. Here, we show the working mechanism and the preliminary results of our experimental method applied to a home-made silica microsphere, using a visible laser beam with a spatial light modulator and a software control.

Journal/Review: SENSORS

Volume: 23      Pages from: 9007  to: 9007

KeyWords: whispering-gallery mode resonator; free-space coupling; Mie scattering; automatic alignment; spatial light modulator
DOI: 10.3390/s23219007