阅读说明：本技术 一种基于光微流微腔的流速计及测量方法 (Flow meter based on optical microfluidic microcavity and measuring method ) 是由 付红岩 陈震旻 谢启浩 于 2019-08-06 设计创作，主要内容包括：本发明公开了一种基于光微流微腔的流速计及测量方法,其中,基于光微流微腔的流速计包括：光微流微腔、锥形光纤、光谱处理装置、信号发生器和光源,所述锥形光纤的锥形端搭靠在光微流微腔上,所述锥形光纤还分别连接所述光源和所述光谱处理装置,所述光谱处理装置包括示波器和探测器或所述光谱仪,所述光源包括宽带光源和可调谐激光源；本发明采用了回音壁模式微腔传感器的结构,通过流体自身的伯努利效应进行传感,对流体的流速进行测量,不易受到环境中电磁场的干扰,且无需加入额外的装置即可进行测量,可以通过调节回音壁模式微腔的尺寸参数(微泡腔的壁厚),便能够大大提高该流速计的灵敏度。(The invention discloses a flow meter and a measuring method based on an optical microfluidic microcavity, wherein the flow meter based on the optical microfluidic microcavity comprises the following components: the optical fiber micro-flow micro-cavity comprises an optical micro-flow micro-cavity, a tapered optical fiber, a spectrum processing device, a signal generator and a light source, wherein the tapered end of the tapered optical fiber is abutted against the optical micro-flow micro-cavity, the tapered optical fiber is also respectively connected with the light source and the spectrum processing device, the spectrum processing device comprises an oscilloscope and a detector or a spectrometer, and the light source comprises a broadband light source and a tunable laser source; the invention adopts the structure of the whispering gallery mode micro-cavity sensor, carries out sensing through the Bernoulli effect of the fluid, carries out measurement on the flow velocity of the fluid, is not easily interfered by an electromagnetic field in the environment, can carry out measurement without adding an additional device, and can greatly improve the sensitivity of the flow velocity meter by adjusting the size parameter (the wall thickness of the micro-cavity) of the whispering gallery mode micro-cavity.)

1. An optical microfluidic microcavity-based flow meter, comprising: the optical fiber micro-cavity comprises an optical micro-cavity, a tapered optical fiber, a spectrum processing device, a signal generator and a light source, wherein the tapered end of the tapered optical fiber is abutted against the optical micro-cavity, the tapered optical fiber is respectively connected with the signal generator and the spectrum processing device, and the light source is used for being introduced into the optical micro-cavity through the tapered optical fiber for resonance processing and then being led out to the spectrum processing device through the tapered optical fiber.

2. The optical microfluidic microcavity-based flow meter according to claim 1, wherein the spectral processing device is comprised of an oscilloscope and a detector or is a spectrometer.

3. The optical microfluidic microcavity-based flow meter of claim 1, wherein the optical microfluidic microcavity is a whispering gallery mode microcavity.

4. the optical microfluidic microcavity-based flow meter of claim 1, wherein the whispering gallery mode microcavity is a micro-bubble type microcavity.

5. the optical microfluidic microcavity-based flow meter of claim 1, wherein the light source is a broadband light source.

6. The optical microfluidic microcavity-based flow meter according to claim 1, wherein the light source is generated by coupling laser light generated by a tunable laser through a tapered fiber coupled with a polarization controller.

7. The optical microfluidic microcavity-based flow meter according to any one of claims 1-5, wherein the whispering gallery mode microcavity and the tapered end of the tapered fiber are encapsulated by a gel.

8. The optical microfluidic microcavity-based flow meter of claims 1-5, wherein the tapered fiber couples to the whispering gallery mode microcavity in a manner that includes under-coupling, critical coupling, or over-coupling.

9. A measuring method of a flow velocity meter based on an optical microfluidic microcavity is characterized by comprising the following steps:

Introducing liquid to be detected into the whispering gallery mode microcavity;

introducing a light source into the whispering gallery mode microcavity for resonance through the tapered optical fiber;

Introducing the light source subjected to the resonance treatment of the whispering gallery mode microcavity into a photoelectric detector through the tapered optical fiber;

And acquiring the transmission spectrum of the whispering gallery mode microcavity, acquiring the movement amount of the resonance wavelength, and combining a resonance formula of the whispering gallery mode microcavity to obtain the flow velocity of the liquid to be detected.

10. The method of using an optical microfluidic microcavity-based flow meter according to claim 9, wherein the resonance formula is: m λ is 2n pi R.

Technical Field

the invention relates to the field of sensors, in particular to a flow meter and a measuring method based on an optical microfluidic microcavity.

Background

The microfluidic chip technology integrates basic operation units of sample preparation, reaction, separation, detection and the like in biological, chemical and medical analysis processes into a micron-scale chip, and automatically completes the whole analysis process.

with the development of microfluidic chip technology, people have increasingly fine requirements on microfluidic control of a system on a chip, and any change in flow rate brings great difference to the microfluidic system, such as in the fields of cell screening, microparticle counting, droplet generation and the like. Thus, a wide variety of microfluidic flow rate sensors have been developed. Such as a microfluidic flow rate sensor based on piezoelectric material, a microfluidic flow rate sensor based on heat transfer, etc. Among them, the microfluidic flow rate sensor based on piezoelectric material is susceptible to interference from electromagnetic fields in the environment; while the second type of sensor usually requires a high power heating of the microfluid, the heating process not only affects the microfluid itself, but also requires additional devices for the introduction of the heating source.

Disclosure of Invention

The present invention is directed to solving, at least to some extent, one of the technical problems in the related art. Therefore, an object of the present invention is to provide a flow meter based on optical microfluidic microcavity, which can sense the flow by the bernoulli effect of the fluid itself, does not need additional devices, and has the characteristics of small size, simplicity, convenience, and low possibility of being interfered by the outside.

therefore, a second object of the present invention is to provide a measurement method using a flow meter based on an optical microfluidic microcavity, which senses by the bernoulli effect of the fluid itself and is not easily interfered by external electromagnetic fields.

The technical scheme adopted by the invention is as follows:

in a first aspect, an embodiment of the present invention provides an optical microfluidic microcavity-based flow velocity meter, including: the optical fiber micro-cavity comprises an optical micro-cavity, a tapered optical fiber, a spectrum processing device, a signal generator and a light source, wherein the tapered end of the tapered optical fiber is abutted against the optical micro-cavity, the tapered optical fiber is also respectively connected with the signal generator and the spectrum processing device, and the light source is used for being introduced into the optical micro-cavity through the tapered optical fiber, forming resonance and being led out to the spectrum processing device through the tapered optical fiber.

further, the spectrum processing device consists of an oscilloscope and a detector or is a spectrometer.

Further, the optical microfluidic microcavity is a whispering gallery mode microcavity.

Further, the whispering gallery mode microcavity is a micro-bubble microcavity.

Further, the light source is a broadband light source.

Further, the light source is a laser generated by a tunable laser.

Further, the coupling mode of the tapered optical fiber and the whispering gallery mode microcavity comprises under coupling, critical coupling or over coupling.

Furthermore, the whispering gallery mode microcavity and the tapered end of the tapered optical fiber are packaged through colloid.

In another aspect, an embodiment of the present invention provides a measurement method using a front flow meter, including:

Introducing liquid to be detected into the whispering gallery mode micro-cavity;

Introducing a light source into the whispering gallery mode microcavity via the tapered fiber and forming resonance;

Introducing the light source subjected to the resonance treatment of the whispering gallery mode microcavity into a photoelectric detector through the tapered optical fiber;

and acquiring the transmission spectrum of the whispering gallery mode microcavity, further acquiring the movement amount of the resonance wavelength, and combining a resonance formula of the whispering gallery mode microcavity to obtain the flow velocity of the liquid to be detected.

further, the resonance formula is: m λ is 2n pi R.

the invention has the beneficial effects that:

The invention adopts the structure of the whispering gallery mode microcavity sensor, senses through the Bernoulli effect of the fluid, measures the flow velocity of the fluid, is not easily interfered by electromagnetic field in the environment, can measure without adding extra devices, and can greatly improve the sensitivity of the flowmeter by only adjusting the size parameters of the whispering gallery mode microcavity, such as the wall thickness parameters of the microbubble cavity (namely, the whispering gallery mode microcavity), for example, the thinner the wall thickness of the microbubble cavity, the easier the mode with high sensitivity is excited. I.e. the mode that will be more sensitive to pressure, and more sensitive to flow rate variations.

The invention adopts a pure optical sensor, detects by the Bernoulli effect principle of microfluid, does not need to add other heating devices and the like additionally, realizes measurement by applying the optical sensor to the microfluidic control chip, and can sense the flow velocity of the fluid with higher sensitivity.

Drawings

FIG. 1 is a schematic view of a flow meter of an optical microfluidic microcavity according to example 1 of the present invention;

FIG. 2 is a schematic view of a flow meter of an optical microfluidic microcavity according to example 2 of the present invention;

FIG. 3 is a schematic view of a flow meter of an optical microfluidic microcavity according to example 3 of the present invention;

FIG. 4 is a graph showing the relationship between the flow rate and the resonance wavelength measured in example 2;

FIG. 5 is a graph showing the relationship between the flow rate and the resonance wavelength measured in example 3;

FIG. 6 is a coupling diagram of an MBR and a tapered fiber;

fig. 7 is a cross-sectional view of the equatorial plane of the MBR.

Reference numerals

the device comprises a 1-MBR microcavity, a 2-tapered optical fiber, a 3-light source, a 4-oscilloscope, a 5-detector, a 6-tunable laser, a 7-polarization controller, an 8-signal generator, a 9-colloid and a 10-spectrometer.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.

In order to better understand the technical solution of the present application, the key terms referred to in the present application are defined:

The fused taper fiber (Tapered fiber) is a special waveguide structure in a single taper or double taper type made by a fused biconical taper method, and can realize transmission and coupling of transmitted optical power.

Optical microcavity (Micro resonator) refers to an optical resonator with dimensions in the range of a few microns to a few hundred microns. The optical cavity provides a feedback loop for the light so that it can oscillate back and forth therein.

A Whispering Gallery Mode Microcavity (WGMM) refers to a type of micron-scale resonant cavity that confines light to the inside of a microcavity for total reflection and forms resonance, and the WGMM abbreviation referred to hereinafter may be meaningless defined as the Whispering gallery mode microcavity.

an MBR microcavity (micro-bubble resonator, MBR) is a protruding capillary quartz tube structure cavity, and has structural parameters such as an outer diameter and a wall thickness. The outer diameter parameter may be tens to hundreds of micrometers, and the wall thickness parameter may be in the order of micrometers to tens of micrometers. By changing the wall thickness parameter of the cavity, the whispering gallery modes with different mode orders can be obtained. When the wall thickness parameter is thinner, the more the optical field distributed in the microcavity is, the more the energy is concentrated in the cavity, and the whispering gallery mode at the moment is more easily influenced by the internal detection environment, has higher sensitivity and can more sense the pressure value change in the cavity. MBR is a whispering gallery mode microcavity of special construction.