Fig. 4

Spectrally selective fingerprinting of analyte from FSFS. a The transmission spectra of the FSFS for pixel P18 (L = 65 μm) and P16 (L = 67 μm) and the imaginary parts of the complex dielectric function (Absorption spectra) of lactose. b, c Normalized transmissions in the presence and absence of analyte molecules with L = 65 μm (b) and 67 μm (c). Measured absorption spectrum of α-lactose (red) and observation of AIT in a FSFS/α-lactose system (dash line) with (d) L = 65 μm (e) L = 67 μm. f Enhancement factor (define as the extinction ratio of the transmission dip of AIT divide by analyte absorption peak) as a function of pixel number, which confirms the robustness of AIT enhancement by FSFS