Figure 2.
(a) 3D model of the experimental apparatus. The waveguides on the photonic chip are accessed with lens-tapered optical fibers. A PDMS flow cell is fixed above the sensor surface, and the liquid is delivered via quartz capillaries; (b) Resonance shift temporal evolution during the injection of a small volume of glucose-water solution (concentration 0.5% wt/wt, refractive index variation 6.5× 10−4 RIU, refractive index unit). The probed resonance comes from the first radial TE (transverse electric) mode of a disk resonator; Experimental data showing the linear relation between resonance wavelength and the bulk refractive index of water-glucose solutions for the first radial TE mode of a disk resonator; Bulk sensitivity and figure of merit measured on the first and second TE radial-family whispering gallery modes (WGMs) of disk and wedge resonators. We considered resonances with center wavelengths close to 1540 nm.