Extra-high sensitive magnetic field sensor based on multiple-mode interference optical microcavity

Abstract

The present invention discloses an extra-high sensitive magnetic field sensor based on multiple-mode interference optical microcavity. Microfiber, a microtubule and a magnetofluid are fixedly sealed to form an optical microcavity; the microfiber is wound around the microtubules in a spiral mode; the microtubule is hollow and internally packaged with the magnetofluid; the input end and the output of the microfiber are respectively connected with a broadband optical source and a spectrum analyzer; the part of the microfiber winding the outer wall of the microtubule is taken as a fiber wrapping region, and the electromagnetic wave is able to generate multiple-mode interference wherein; the electromagnetic wave is emitted by the broadband optical source and is transmitted to the fiber wrapping region through the microfiber; and the evanescent wave part of the electromagnetic wave in the fiber wrapping region is able to pass through the microtubule wall into the magnetofluid, pass through the electromagnetic wave of the optical microcavity and then pass through the microfiber to output to a spectrum analyzer. The extra-high sensitive magnetic field sensor based on a multiple-mode interference optical microcavity is provided with a structure winding the microfiber onto the microtubule so as to greatly increase the contact of the electromagnetic wave and the magnetofluid, and therefore the sensitivity is higher.

Description

technical field [0001] The invention relates to an ultra-sensitive magnetic field sensor based on a multi-mode interference optical microcavity, especially a magnetic field sensor with extremely high sensitivity. Background technique [0002] Optical microcavity is an important photonic device, which has the advantages of high quality factor and small mode volume, and has attracted extensive attention in fundamental and applied fields, such as cavity quantum electrodynamics, nonlinear optics, extremely low threshold sensitivity sensor etc. The optical microcavity sensor with whispering gallery resonance mode is small in size, high in sensitivity and low in detection limit, and can realize label-free detection of biochemical molecules with high detection reliability, which is of great practical value. [0003] Magnetic fluid is a stable colloidal solution formed by uniformly dispersing ferromagnetic particles coated with surfactants in a suitable carrier liquid. As a new fu...

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Problems solved by technology

[0005] Aiming at the problem of low sensitivity of current magnetic field sensors, the present inventio

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