Surface plasmon enhanced fluorescence sensor and method for measuring refractive index change

Abstract

The invention discloses a surface plasma enhanced fluorescence sensor and a measurement method thereof. The surface plasma enhanced fluorescence sensor comprises a laser device, a polaroid, a lens, aprism, a surface plasma enhanced fluorescence sensing chip, an adjustable voltage output device, a probe and a sample layer, wherein the surface plasma enhanced fluorescence sensing chip sequentiallycomprises a glass substrate, a WCSPR device, a buffer layer and a sample tank; the WCSPR device comprises an upper metal layer, a refractive index adjusting medium layer and a lower metal layer; the sample tank is arranged on the lower surface of the buffer layer, and a gap is formed between the sample tank and the lower surface of the buffer layer; and the refractive index of a sample in the sample tank is 1.33. According to the surface plasma enhanced fluorescence sensor, by changing the refractive indexes of a medium layer or a combination through external field refractive index adjustment,the electric field distribution of surface plasma waves in the buffer layer can be realized, and the detection of the electric field distribution in the medium layer and the adjustment of a local electric field enhancement coefficient can be realized.

Description

technical field [0001] The invention relates to the field of sensors and sensor technologies, in particular to a surface plasmon enhanced fluorescence sensor and a method for measuring changes in refractive index. Background technique [0002] When light irradiates fluorescent compound molecules, the energy of the light causes some electrons around some nuclei in the molecule to transition from the ground state to singlet states such as the first excited singlet state or the second excited singlet state. Since the singlet state such as the above-mentioned singlet state is unstable, the above-mentioned electrons return to the ground state and release energy in the form of light, thereby generating fluorescence. [0003] The existing literature reports that the intensity of surface-enhanced fluorescence is directly proportional to the ratio of the electric field intensity on the medium side to the electric field intensity on the metal film side at the metal film-dielectric int...

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Problems solved by technology

[0006] Second, LRSPR devices are difficult to adjust the local field enhancement coefficient

The thickness of the fluorescent compound molecular layer is usually much smaller than the surface plasmon wave propagation distance. Therefore, after the above-mentioned metal thin film and dielectric layer structure parameters are fixed in the existing LRSPR device, the electric field distribution near the metal thin film-dielectric layer and the local field enhancement coefficient are constant. It is difficult to adjust the above-mentioned electric field distribution and local field enhancement coefficient according to the thickness of different fluorescent compound molecular layers to obtain the best SPEF signal amplification effect

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