Fig. 4: l-proline sensing results.
From: High-sensitivity nanophotonic sensors with passive trapping of analyte molecules in hot spots
a, b Reflection spectra of two sets of devices with a 200 nm wide nano-trenches and b 450 nm wide nano-trenches before (dot-dashed curves) and after (solid curves) introducing a 1 μL droplet of 10 μg/mL proline solution. The Al ribbon widths of the devices are specified in the legends. c Reflection spectra of two devices with 450 nm wide nano-trench, before (dot-dashed curves) and after (solid curves) introducing a 1 μL droplet of 1 μg/mL proline solution. d Upper panel: reflection spectra of the device with 450 nm wide nano-trenches and 1.4 μm-wide Al ribbons before (dot-dashed black curve) and after (solid red curve) introducing a 1 μL droplet of 0.2 μg/mL proline solution. Lower panel: the differential reflection spectra extracted from the spectra in the upper panel. The red (blue) curve is the differential spectrum before (after) the procedure for removing/reducing the interfering spectral features owing to water vapor absorption lines. Both differential spectra show clear spectral features associated with the proline absorption lines
