Evanescent-wave-based fiber SERS (Surface Enhanced Raman Scattering) probe and preparation method thereof

Abstract

The invention discloses an evanescent-wave-based fiber SERS probe and a preparation method thereof. The evanescent-wave-based fiber probe comprises an evanescent-wave structure of an optical fiber anda noble metal micro-nano structure having a Fano resonance effect. The noble metal micro-nano structure is arranged on the surface of the evanescent-wave structure of the optical fiber. The Raman excitation light and the Raman signal light of the molecules to-be-detected are respectively arranged at a bright mode and a dark mode of the Fano resonance of the noble metal micro-nano structure, whenthe probe is used. According to the evanescent-wave-based fiber SERS probe and the preparation method thereof, the preparation method sets the noble metal micro-nano structure having the Fano resonance effect on the surface of the evanescent-wave structure of the optical fiber, utilizes the bright mode to realize an effective excitation of the Raman signal light of the molecule to-be-detected, andmeanwhile, utilizes the dark mode to realize the low loss transmission of the Raman signal light of the molecule to-be-detected in the optical fiber, thereby solving the bottleneck problem that the sensitivity of the probe is limited by a SERS saturation phenomenon in the current evanescent-wave-based fiber SERS probe.

Description

technical field [0001] The invention relates to the field of surface-enhanced Raman spectroscopy detection, in particular to an evanescent wave optical fiber surface-enhanced Raman scattering probe and a preparation method thereof. Background technique [0002] The evanescent fiber SERS (surface enhanced Raman scattering) probe refers to the preparation of noble metal nanoparticles or structures on the surface of the evanescent fiber structure (such as tapered fiber, micro-nano fiber, D-type fiber, etc.) form. On the one hand, the evanescent wave transmission characteristics of optical fiber can greatly increase the SERS interaction area, which is beneficial to improve the detection sensitivity; on the other hand, since the evanescent wave itself does not carry energy, it can effectively avoid the noble metal nanoparticles and the samples to be tested during the SERS detection process. The photothermal damage of molecules has important application prospects in the fields of...

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Problems solved by technology

[0003] However, in the evanescent wave optical fiber SERS probe, although the optical fiber itself has a very low transmission loss, the absorption and scattering effects of the nanoparticles will cause a large SERS transmission loss after the noble metal nanoparticles are adsorbed on the surface.

However, when the generation of SERS signal per unit length is less than or equal to its transmission loss, the total strength of SERS signal will no longer continue to increase with the increase of probe length, that is, the phenomenon of SERS saturation will be reached, which seriously limits the current evanescent wave fiber SERS probe. Increased sensitivity

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