Fig. 1. (a) Schematic of the cone-shaped inwall capillary-based microsphere resonator. (b) A typical Fano resonance and relevant parameter definitions.

Fig. 2. (a) Simulation of Fano resonances versus normalized frequency and δ (the reflection is normalized). (b)–(e) are the progression of PR as a function of δ in four quadrants of π/4 each.

Fig. 3. (a)–(c) Simulations when τ are 0.9, 0.95, and 0.99, respectively. (d) Illustration of the changing process of slope.

Fig. 4. Simulation of (a) the maximum and (b) the minimum versus t, when τ is 0.9, 0.95, and 0.99.

Fig. 5. When τ is 0.9, 0.95, and 0.99, simulation of (a) Δθ/π and (b) contrast (dB).

Fig. 6. (a)–(c) Simulations when δ adopted as 0, 0.5π, and 0.265π, respectively, with r increasing from 0 to 100%. (d) The slope and width of the Fano resonances with r increasing from 10% to 100%.

Fig. 7. (a) Spectra, (b) peak wavelength shifts, and (c) width of a Fano resonance when temperature increases.

Fig. 8. (a) Spectra of the device in solutions with different refractive indices. (b) Intensity of the resonance peak at 1529 nm marked with a blue circle versus the refractive index.