Whispering gallery mode spherical optical microcavity refractive index sensor and measurement device based on surface plasmon

Abstract

The invention provides a whispering gallery mode spherical optical microcavity refractive index sensor and a measuring device based on surface plasmon, making full use of the high quality factor characteristics of the whispering gallery mode optical microcavity, and by coating the surface of the optical microcavity with a gold layer to excite the Surface plasmon can improve the surface energy and refractive index sensing sensitivity of the optical microcavity, and realize the measurement of the refractive index of the external medium. The optical microcavity refractive index sensor of the present invention comprises a micro-nano optical fiber and a whispering gallery mode spherical optical microcavity, wherein the micro-nano fiber is in contact with the whispering gallery mode spherical optical microcavity; the surface of the whispering gallery mode spherical optical microcavity is A crescent-shaped gold layer is plated on top to excite surface plasmons and enhance the sensitivity of the spherical optical microcavity to changes in the refractive index of the external medium. The invention has the advantages of small size, simple preparation method, easy integration and the like, and can be applied to the fields of chemical or biological sensing and 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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