Fig. 2

Schematic of the (a) experimental platform and (b) fiber taper-coupled micro-resonator (coupling position is controlled by tunable bracket). The light from a tunable laser was coupled into the LC-amplified optofluidic resonator through the fiber taper to acquire the WGM spectrum and was further received in spectrometer. The addition of protein molecules led to the orientation transition of LC and (c) the wavelength shift of WGM spectrum. (d) WGM laser spectral responses of LC-amplified optofluidic resonator under a controlled experiment (0 g/ml BSA) at 0 min (purple curve) and 15 mins (red curve), respectively. In addition, effect of the wall thickness on spectral responses was studied. (e) Illustration of intensity distribution of the incident laser beam for thick (left) and thin (right) wall of the microcavity. (f) WGM spectral responses of LC-amplified optofluidic resonator with various wall thicknesses at 1 mg/ml BSA within 15 mins