Fig. 6: Demonstration of molecular identification of low concentration alcohols with multi-dimensional sensing signal from WMHNA by machine learning.
From: Wavelength-multiplexed hook nanoantennas for machine learning enabled mid-infrared spectroscopy
a The broadband spectra of WMHNA under different analytes. All alcohol solvents are diluted to 1% in DI water. b The extracted absorption spectra of different alcohol solvents from WMHNA. c The corresponding second-order derivative of absorption spectra in (b). d The reflection spectra of sensing data with different analytes states. e The machine learning processed spectra of WMHNA after dimension reduction by principal component analysis. the first principal component (PC 1) represents the antenna loading effect of water absorption peaks at 6.0 μm. The second principal component (PC 2) represents the wavelength shift of WMHNA due to the refractive index of the analyte. The third principal component (PC 3) represents the fingerprint absorption of molecules. f The weight of scores of each spectrum in three-dimensional space after PCA for WMHNA. Each cluster indicates one type of molecule and its mixtures. g The confusion map for machine learning outcome indicates the 100% accuracy of molecular identification.
