Localized optical resonances in low refractive index rolled-up microtube cavity for liquid-core optofluidic detection

Abstract

Spatially localized high order axial resonant modes are observed in a SiO/SiO2-based microtube cavity rolled-up from a prestrained nanomembrane. A diameter variation of the tube structure is revealed which provides localized axial confinement. Optofluidic detection is demonstrated by filling the tube core with salt solution and subsequently detecting the shifts of spectral mode positions and axial mode spacings. A sensing methodology is proposed by monitoring axial mode spacing changes.