A metamaterial-based surface-enhanced infrared substrate and its molecular detection method

Abstract

The invention discloses a surface-enhanced infrared substrate based on a metamaterial and a molecular detection method thereof. The infrared substrate is sequentially provided with a supporting substrate, a uniform surface plasmon thin film and a periodic array; by regulating the period of the periodic array, the infrared The uniform surface plasmon thin film of the substrate is coupled with the electric dipole mode, so that the resonance wavelength of the latter changes, and the near-field electric field strength is enhanced; when the molecules to be measured are adsorbed or prepared on the infrared substrate, through the external infrared The spectroscopic equipment can be used to obtain the surface-enhanced infrared absorption spectrum of the molecule to be tested. The uniform surface plasmon thin film is made of a metal material or a dielectric material with a negative real part of the dielectric constant, and its thickness is greater than 200 nm. The detection methods are: (1) experimental test spectrum acquisition; (2) theoretical simulation spectrum acquisition; (3) evaluation function construction; (4) inversion solution; (5) result analysis.

Description

technical field [0001] The invention relates to the technical field of molecular detection, in particular to a metamaterial-based surface-enhanced infrared substrate and a molecular detection method thereof. Background technique [0002] Surface-enhanced spectroscopy utilizes near-field enhancement near rough surfaces or rationally designed metamaterial structures to enhance the scattered or reflected signals of attached molecules, thereby significantly improving the detection limit, even down to the single-molecule level. Since most molecules have their characteristic absorption fingerprints in the infrared wavelength range, infrared spectroscopy has become one of the most effective methods for identifying unknown organic species, which is called surface-enhanced infrared absorption spectroscopy (SEIRA). Therefore, SEIRA provides a powerful and reliable tool to detect trace molecules, as well as to study molecular conformational changes and molecular interactions. [0003]...

AI Technical Summary

Problems solved by technology

[0009] However, most of the above-mentioned methods involving optical constants have complex test procedures and low measurement accuracy, and because the molecular fingerprint vibration itself is very weak, it is difficult to achieve effective and reliable inversion of molecular optical constants, and only the real part of optical constants can be detected, which is difficult to accurately detect Imaginary part of optical constant

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