Schematic of the experimental setup used for measurement.
(a) Reflectance spectrum of the sensing plate obtained by irradiation with a 760-nm laser (open circles), and that obtained by the simulation (solid curve). The plate surface was covered with water. The angular dependence of the numerically obtained electric-field amplitude, normalized by that of the incident light, is also shown by the broken curve. (b) Distribution of electric field at a light incidence angle of θ e. The green lines indicate the boundary of the layers of the sensing plate. The normalized amplitude is represented by the color bar.
Kinetic behavior of luminescence obtained upon a flow of the solution of streptavidin-Alexa Fluor 750 with concentrations from 1 pM to 10 nM. Note that the angle was fixed at θ r during the experiment. Injection times of streptavidin-Alexa-Fluor-750 solutions and the PBS buffers for rinsing are clearly indicated by the arrows. The solid lines represent the linear fits of the signals at the initial stage (Δt = 4 min) after solution injection.
Slopes of the luminescence signal, obtained from the solid lines in Fig. 3 , as a function of the concentration of the streptavidin-Alexa-Fluor-750 solution. The solid line indicates the linear fit of the experimental results. The broken line represents the baseline fluctuation level of the system.
Numerically obtained normalized-electric-field amplitude at θ e as a function of the thicknesses of the a-SiO2 and c-Si layers. The normalized amplitude is represented by the color bar.
Luminescence (closed circles) and reflectance spectra of the plates covered with water (open circles), obtained by irradiation with lasers having wavelengths of 760 (a), 633 (b), and 532 nm (c). Note that no fluorescent dyes were attached to the plate surface at this stage.
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