Fig. 5

Graph showing the dependence of the amplified optical signal on the distance, angle of incident light, and application. a shows that the plasmonic nanostructure amplifies the optical intensity when the plasmonic and incident light wave vectors are matched. When the angle of incident light is 30°, the plasmonic and incident light wave vectors are matched. b shows the amplification depending on the distance, demonstrating that the plasmonic nanostructure was more affected when the optical intensity was weak. c shows AFM data which without the laser(left) and with laser(right). d shows the amplitudes of oxyhemoglobin and deoxyhemoglobin for the plasmonic nanostructure, which were used as controls. This subfigure also shows the amplitudes of oxyhemoglobin and deoxyhemoglobin for the plasmonic nanostructure with detectors 1 and 2. Detector 2 applied the plasmonic nanostructure at 30°. also shows the fNIRS spectra, indicating that a higher intensity was obtained with the plasmonic nanostructure (right) than with the original structure (left). e shows the fluorescence image and amplification graph; the amplitude of the optical signal is 1.6 times higher than that of the original signal