Microscopic and SEM images of 2S2G microspheres.

Yang, Z.,Wu, Y*., et al.IEEE Photonics Technology Letters 29(1), 66-69(2017).

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Chalcogenide glasses are popular base materials for infrared optical/photonic devices because of their various desirable properties in the infrared spectrum, such as wide transmission windows, high refractive indices, low phonon energies, and good solubilities to Rare Earth Ions (REIs).

Recently, Zhengsheng Yang and Yuehao Wu et al. fabricated gallium germanium antimony sulfide (2S2G) chalcogenide glass and demonstrate whispering gallery modes (WGMs) in the wavelength range of 1.65–2 μm. Typical quality factors (Q factors) measured with 2S2G microspheres fabricated in our lab are approximately 6×104. Compared with other chalcogenide glasses used in microsphere resonators, this 2S2G glass has a lower melting temperature and a higher characteristic temperature, and therefore, the fabrication temperature in the sphere-forming process can be reduced and the crystallization problem can be mitigated. We also demonstrate apparent shifts of resonant peaks in the measured WGMs as the environmental temperature varies, implying that these 2S2G microspheres can be used as compact temperature sensors. The thermal sensitivity measured with a 108.52-μm-diameter 2S2G microsphere is 28 pm/°C.

Thermal shift of a resonant peak (1843.91 nm) obtained with a 108.52-μm diameter 2S2G microsphere.

Paper link:https://10.1109/LPT.2016.2628810