Echo wall mode spherical optical micro-cavity refractive index sensor based on surface plasmas and measuring device

Abstract

The invention provides an echo wall mode spherical optical micro-cavity refractive index sensor based on surface plasmas and a measuring device. The high-quality factor characteristic of the echo wallmode optical micro-cavity is fully utilized, the surface of the optical micro-cavity is plated with a gold layer to excite surface plasmas, the surface energy and refractive index sensing sensitivityof the optical micro-cavity are improved, and the refractive index of an external medium is measured. The optical micro-cavity refractive index sensor comprises a micro-nano optical fiber and an echowall mode spherical optical micro-cavity, wherein the micro-nano optical fiber is in contact coupling with the echo wall mode spherical optical micro-cavity, and the surface of the echo wall mode spherical optical micro-cavity is plated with a crescent gold layer to excite surface plasmas so as to enhance the sensitivity of the spherical optical micro-cavity to the change of the refractive indexof an external medium. The sensor has the advantages of small size, simple preparation method, easiness in integration and the like, and can be applied to the fields of chemical or biological sensingand the like.

Description

technical field [0001] The invention relates to the technical field of optical fiber devices, in particular to a whispering gallery mode spherical optical microcavity refractive index sensor and a measuring device based on surface plasmons. Background technique [0002] Whispering gallery mode optical microcavity is an optical element that confines the light field in a micron-scale space area based on the total internal reflection effect. It has the advantages of high energy density, high quality factor, and small space size. Its mode field is mainly distributed in the optical Inside the microcavity, but part of the energy exists outside the optical microcavity in the form of evanescent field. The evanescent field of the optical microcavity can sense the change of the refractive index of the external medium, and then convert it into the change of the transmission line, so as to realize the sensing and measurement of the external refractive index. However, due to the large r...

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Problems solved by technology

However, sensors coated with sensitive materials are only sensitive to changes in the refractive index of a specific object to be measured, and are not universal, while the preparation of microbubble chambers is complicated and easily broken, making it less practical

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