Abstract
Microsphere resonators based on chalcogenide glasses combine the superior optical properties of microsphere resonators (such as high Q-factors and small mode volumes) and excellent material properties of chalcogenide glasses in the infrared spectrum (such as good transmissivities, high refractive indices, and low phonon energies), and thus have promising applications in the fields of low-threshold infrared lasers, nonlinear Raman amplifiers/lasers, and narrow bandwidth infrared filters.
In this work, the infrared microsphere resonators are built by using a novel chalcogenide glass composition of 75 GeS2-15 Ga2S3-10 CsI (Ge-Ga-S), doped with 1.3 wt% Tm. Compared with previously reported chalcogenide microsphere resonators fabricated with As2S3 and gallium lanthanum sulfide (Ga-La-S) glasses, the proposed Ge-Ga-S glass does not contain the toxic element of As nor the expensive rare earth element of La, and thus is more environmentally friendly and cost-effective for fabricators and users. We first fabricate bul