Enhancing the Robustness of the Microcavity Coupling System

A novel method to enhance the robustness of the microcavity coupling system (MCS) is presented by encapsulating and solidifying the MCS with a low refractive index (RI) curable UV polymer. The encapsulating process is illustrated in detail for a typical microsphere with a radius of R about 240 µm. Three differences of the resonant characteristics before and after the package are observed and analyzed. The first two differences refer to the enhancement of the coupling strength and the shift of the resonant spectrum to the longer wavelength, which are both mainly because of the microsphere surrounding RI variation. Another difference is the quality factor (Q-factor) which decreases from 7.8×10⁷ to 8.7×10⁶ after the package due to the polymer absorption. Moreover, rotation testing experiments have been carried out to verify the robustness of the package MCS. Experimental results demonstrate that the packaged MCR has much better robust performance than the un-package sample. The enhancement of the robustness greatly promotes the microcavity research from fundamental investigations to application fields.