Fig. 4: Dependence of the molecular-vibrational contrast at 1508 cm-1 on the thickness of the molecular layer.
From: On-chip phonon-enhanced IR near-field detection of molecular vibrations
a The red and blue circles show \(\varDelta\) and \({\varDelta }_{{{{\rm{t}}}}}\) (indicated in Fig. 3b, f) extracted from experimental normalized PC spectra as a function of the CBP layer, respectively (the spectra are shown in Supplementary Note 9 in Supplementary Fig. 13). The red and blue curves show\(\,\varDelta\) and \({\varDelta }_{{{{\rm{t}}}}}\) (indicated in Fig. 3c, g) extracted from simulated normalized absorption spectra, respectively (the spectra are shown in Supplementary Note 8 in Supplementary Fig. 12b, d). b, The green circles and curve show the enhancement of molecular-vibrational contrast, \(\varDelta /{\varDelta }_{{{{\rm{t}}}}}\), calculated from the experimental and simulated values from the panel a, respectively. The inset shows that when a thick molecular layer is placed on top of the detector, only a portion of the molecules interact with the near fields of the detector. a,b, The values of the simulated red and green curves were divided by 1.5 for visual comparison with the experimental data. Source data are provided as a Source Data file.
