Micro-droplet sensing device and method using same to measure refractivity

Abstract

The invention provides a micro-droplet sensing device and a method using the same to measure refractivity. A single mode fiber forms a taper area through tapering, two ends of the single mode fiber are connected with a wide-spectrum light source and a spectrograph respectively, the taper area is placed in environment liquid, and annular core fiber optical tweezers control a micro-droplet to be close to the taper area; light emitted by the wide-spectrum light source is transmitted in the single mode fiber, is coupled into the micro-droplet by means of an evanescent field when going through the taper area and generates resonance in the mode of an echo wall, transmission light intensity at a resonance wavelength is reduced sharply to form a resonance valley, and the spectrograph is used to collect transmission light for spectrum analysis. The annular core fiber optical tweezers are utilized to control the micro-droplet to enable the same to form a perfect ball cavity, so that the problem that a solid ball echo wall sensor cannot form echo wall resonance due to unsmooth and defective surface of a solid ball is solved, and the micro-droplet is more sensitive to environment changing. The micro-droplet sensing device has wide application in the aspect of environment monitoring.

Description

technical field [0001] The invention relates to an optical fiber sensing device, in particular to a device for sensing refractive index and temperature realized by using micro-droplet echoing gallery resonance. Background technique [0002] The tapered fiber-coupled microsphere is a classic whispering gallery mode resonance structure. The light can be efficiently coupled into and out of the microsphere cavity by using the evanescent field on the surface of the tapered fiber cone. The light coupled into the microsphere is in the microsphere Multiple total reflections occur on the inner surface, when the light wavelength λ satisfies Where n is the refractive index of the microsphere, R is the radius of the microsphere, and N is a positive integer. The light of this wavelength will generate a whispering gallery mode resonance in the microsphere, and the light is confined in the microsphere cavity, so the transmission spectrum is at this wavelength The sharp decrease of the li...

AI Technical Summary

Problems solved by technology

This method uses a solid ball as a microsphere cavity to realize temperature sensing, but because the surface of the solid ball is incomplete, the resonance of the whispering gallery will be flawed, and the change of the solid ball with temperature is not as sensitive as that of the liquid ball, so the sensitivity is not high.

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