Comprehensive Numerical Analysis of Temperature Sensitivity of Spherical Microresonators Based on Silica and Soft Glasses

In recent years, the use of optical methods for temperature measurements has been attracting increased attention. High-performance miniature sensors can be based on glass microspheres with whispering gallery modes (WGMs), as their resonant frequencies shift in response to the ambient parameter variations. In this work, we present a systematic comprehensive numerical analysis of temperature microsensors with a realistic design based on standard silica fibers, as well as commercially available special soft glass fibers (GeO2, tellurite, As2S3, and As2Se3). Possible experimental implementation and some practical recommendations are discussed in detail. We developed a realistic numerical model that takes into account the spectral and temperature dependence of basic glass characteristics in a wide parameter range. To the best of our knowledge, spherical temperature microsensors based on the majority of the considered glass fibers have been investigated for the first time. The highest sensitivity d lambda/dT was obtained for the chalcogenide As2Se3 and As2S3 microspheres: for measurements at room temperature conditions at a wavelength of lambda = 1.55 mu m, it was as high as 57 pm/K and 36 pm/K, correspondingly, which is several times larger than for common silica glass (9.4 pm/K). Importantly, d lambda/dT was almost independent of microresonator size, WGM polarization and structure; this is a practically crucial feature showing the robustness of the sensing devices of the proposed design.

Automated summary

In recent years, optical methods for temperature measurements have gained increasing attention. Glass microspheres with whispering gallery modes (WGMs) can serve as high-performance miniature sensors due to their resonant frequency shift in response to ambient parameter changes. This study presents a comprehensive numerical analysis of temperature microsensors based on standard silica fibers and commercially available special soft glass fibers, providing experimental implementation and practical recommendations. The results show that chalcogenide As2Se3 and As2S3 microspheres have the highest sensitivity, with d lambda/dT values of 57 pm/K and 36 pm/K, respectively, significantly higher than common silica glass (9.4 pm/K). The sensing devices of the proposed design exhibit robustness with respect to microresonator size, WGM polarization, and structure.