Fig. 1. (a) Schematic diagram of the proposed sensor. (b) Spectrum changes under three stages. Blue and orange dashed lines represent variations of the resonance wavelength and signal intensity with time, respectively.

Fig. 2. (a) Simulation result of displacement under droplet gravity when the length l1 is 13,000 μm and l2 is 17,000 μm. Inset on top right shows the established model in COMSOL; inset on bottom left is the enlarged view at the coupling point. (b) Influence of droplet gravity on device displacement when l2 is 17,000 μm. (c) Influence of length l2 on device displacement when droplet gravity is 0.085 mN.

Fig. 3. Schematic diagram of liquid mass and liquid identification sensing system. Inset in the dashed box shows the microscopic image of the OFMBR. TSL, tunable semiconductor laser; CCD, charge coupled device; PD, photodetector; PC, polarization controller.

Fig. 4. (a) Resonance wavelength of two pendant droplet changes with flow time as the flow rate of the syringe pump is set as 20 μL/min. (b) Dependence of resonance wavelength shifts on flow time. Dots in the figure represent experiment data; the lines are fitting lines.

Fig. 5. Resonance wavelength dependence and radius of pendant droplet dependence on droplet mass as the flow rates are (a) 10 μL/min and (b) 30 μL/min.

Fig. 6. (a) Detached time for distilled water and alcohol at different flow rates. (b) Dependence of wavelength shift on flow time for distilled water and alcohol.

Fig. 7. Comparison of pendant droplet radius between experiment (red dots) and theoretical (blue dots) values. Right side shows images of pendant droplet of distilled water at different moments.