CN109507162B - Laser detection system and method based on resonant cavity and FRET effect - Google Patents

Abstract

A laser detection system and method based on resonant cavity and FRET effect, including laser source module, resonant cavity module, optical alignment module and signal receiving module, the laser source module is used for providing the laser source, the optical alignment module is used for coupling the laser source to the resonant cavity module and collecting the signal light produced by the resonant cavity module to the spectrometer; the resonant cavity module is used for generating optical resonance and FRET effect, and comprises a microcavity capable of generating optical resonance and a fluorescent acceptor substance capable of generating FRET effect around the microcavity; the signal receiving module is used for receiving, analyzing and storing the signal light. The laser source module generates laser, the laser source is coupled to the resonant cavity module through the optical collimation module, the micro-cavity is excited to generate resonance, and then fluorescent acceptor substances around the micro-cavity are excited to generate FRET effect to generate signal light; if the obtained signal light has specificity difference with the standard signal light, the existence of the molecule to be detected is indicated, and the detection of trace substances outside the resonant cavity is realized.

Description

Laser detection system and method based on resonant cavity and FRET effect

Technical Field

The invention is mainly based on the optical resonant cavity of whispering gallery mode and the FRET (fluorescence resonance energy transfer) effect. Pumping and exciting the fluorescent small ball by using a specific laser source, generating a cluster of laser by the small ball, exciting a fluorescent medium outside the small ball by FRET effect, outputting another cluster of laser with adjacent wave band by the system, and measuring the frequency shift of two laser spectrums so as to realize the ultra-high sensitivity sensing on the biological molecules.

Background

The Whispering Gallery Mode (WGM) phenomenon exists in beijing altar and london st paul church, mainly because the sound waves are constantly reflected on a curved and smooth wall surface and the loss is extremely low, so that a person speaks at a certain point of the wall edge, and the person still can hear at another point of the wall surface far away. The echo wall principle of the optical mode is similar to that of the optical mode, the glass beads made of quartz materials through fusion sintering are the most original echo wall micro-cavity, and because the roughness degree of the inner boundary of the small ball is small, the difference of the internal refractive index and the external refractive index is large, light beams striking the small ball are easy to be totally reflected in the cavity and are not easy to be scattered and absorbed. Because the size of the sphere is close to the wavelength band of light, photons resonate within the cavity, and a simple miniature laser with a low threshold can be formed. The components of the resonant cavity extend from various types of silicon-based materials or crystals to semiconductors and polymers, and can have various cavity modes, such as spherical, microdisk, double-column ring and the like. The advantages of small size, various structures, simple preparation and the like make the whispering gallery mode microcavity attract more and more researchers.

Compared with the traditional Fabry-Perot cavity, the size of the echo wall cavity is smaller, the integration is easier, and the self-body has extremely high quality factor, the size can be different from hundreds of nanometers to 500 micrometers, the micro-cavities with different refractive indexes and absorption rates have different characteristics, and the micro-cavity has very good application prospect in the fields of optical sensing, filter delayers, nonlinear optics, biological imaging and the like. For example, when the size of the optical cavity is on the order of microns, the output changes are observed with small perturbations, and the echo wall ball can be used as an extremely sensitive optical micro-motion sensing element. The coupling system based on the waveguide and the microcavity can couple signals consistent with the resonant wavelength of the cavity, so that the echo wall ball can play the role of a filter. In recent years, the echo wall mode microcavity realizes the detection of protein by utilizing a microsphere resonant cavity in the field of biophotonic science, such as F, Vollmer and the like in 2002, and a team of the family in 2008 realizes the detection of single virus by utilizing the echo wall globule. In 2011, Seok Hyun Yun of harvard university first realized a unicellular biological laser, and then researchers combined the echo wall concept with cells to find that the cells can phagocytose echo wall globules with the size equivalent to the size of the cells themselves, and can normally survive and metabolize for about one week until programmed apoptosis. By the feedback light of the cell-echo wall, various optical data can be obtained and analyzed. It can be seen that the echo wall cavity has great potential in the field of optical biophotonics, and future research work on the echo wall cavity will focus on the design of an integrated micro-platform.

The FRET effect is a phenomenon in which excitation energy is conducted from a donor molecule (D) to an acceptor molecule (A) at a distance of 1 to 10 nm. For a particular donor-acceptor pair, the energy lost by the donor is the energy gained by the acceptor. FRET efficiency

Distance from dipole

Satisfy the formula

Wherein the coefficient

Determined by the spectral characteristics of the dipole itself,

refers to the distance between dipoles at which the FRET efficiency reaches 50%. FRET is now one of the few technical approaches that enable detection of distances on the nanometer scale, and of course relies on the development of new fluorescent probe dyes and increasingly optimized algorithms.

Disclosure of Invention

The invention realizes the detection of trace substances outside the resonant cavity by utilizing the fluorescence-doped micro resonant cavity and the FRET principle. In the presence of the substance to be detected, the laser generated by pumping the fluorescence-doped micro-resonator with the light source excites another fluorescent substance (fluorescence acceptor) outside the microsphere through FRET effect, so that the laser output is generated. By adjusting the concentration of the fluorescent doping substance, two beams of laser can be radiated simultaneously. The wave spectrums of the two beams of light can shift along with the concentration change of the object to be detected, so that the sensing detection of the object to be detected is realized.

A473 nm laser source is adopted to excite a dye Dragon Green (DG) doped whispering gallery globule, the globule is excited to generate a fluorescence peak with the wavelength of 500-600 nm, and after the power of the light source is further improved, a cluster of laser peaks with the wave band of 520-540 nm can be generated after the threshold value of a resonant cavity is reached. The invention has been verified through experiments that energy in the pellet can be partially transferred to the outside of the pellet by using FRET effect, liquid in which fluorescent dye is dissolved outside the pellet is continuously excited, a new fluorescence peak is generated in a near-far long wave band, or a cluster of laser peaks between 540nm and 570nm are generated after a threshold value is reached. Theory predicts that similar "spectral shift" effects can be produced in other bands.

The invention mainly aims to construct a microcavity-based optical system and a microcavity-based optical method for precise biosensing. The system comprises a laser source module (1), a resonant cavity module (2), an optical collimation module (3) and a signal receiving module (4), wherein the laser source module (1) is used for providing a laser source and comprises a laser source (11) and a continuous attenuation sheet (12); the optical collimation module (3) is used for coupling the laser source to the resonant cavity module (2) and collecting signal light generated by the resonant cavity module (2) into a spectrometer, and comprises a first microscope objective (31), a second microscope objective (32), a dichroic mirror (33), a convex lens (34) and a camera (35), wherein the focal lengths of the first microscope objective and the second microscope objective are coincident; the resonant cavity module (2) is used for generating optical resonance and FRET effect, and comprises a microcavity capable of generating optical resonance, a fluorescence acceptor substance capable of generating FRET effect around the microcavity, and a three-dimensional adjusting frame; the signal receiving module (4) is used for receiving, analyzing and storing signal light and comprises a filter plate (41), a convex lens (42) and a spectrometer (43); the output laser of laser source (11) has produced signal light through continuous attenuation piece (12) in proper order, dichroic mirror (33), first micro objective (31), resonant cavity module (2), signal light divide into two parts, partly signal light passes through second micro objective (32) in proper order, filter plate (41), convex lens (42), it receives to get into spectrum appearance (43) at last, analysis, storage, another part signal light passes through first micro objective (31) in proper order, dichroic mirror (33), convex lens (34) and camera (35), a coupling effect for real-time observation laser and resonant cavity, according to the image of real-time observation, realize best coupling with three-dimensional adjustment frame adjustment microcavity position.

The two first micro objective lenses (31) and the second micro objective lenses (32) with coincident focal lengths can be replaced by two convex lenses, or one micro objective lens and one convex lens.

The camera (35) can be a CCD or CMOS image sensor or a white board.

The microcavity material can be quartz, doped quartz, polymer or material capable of forming optical resonance.

The micro-cavity can be in the form of a microsphere, a micro-disk, a micro-ring, a micro-tube or a micro-polygon, and the geometric radius of the micro-cavity is larger than the single wavelength size of the excitation light source (1) and is smaller than 1 mm.

The micro-cavity may be added with or without a fluorescent substance.

The fluorescence acceptor substance outside the cavity can be in a gas state, a liquid state or a solid state, and the refractive index of the fluorescence acceptor substance is smaller than that in the resonant cavity; the extra-luminal fluorescent acceptor substance may comprise a plurality of fluorescent substances for the multiple FRET effect to occur.

The resonant cavity module (2) can be transformed into a microfluidic structure.

The resonance frequency of the excitation light source module (1) is the same as the intrinsic resonance frequency of the resonant cavity module (2).

A laser detection method based on resonant cavity and FRET effect, laser source module (1) generates laser, the laser source is coupled to resonant cavity module (2) through optical collimation module (3), the micro cavity is excited to generate resonance, and further the fluorescence acceptor matter around the micro cavity is excited to generate FRET effect, and signal light is generated;

If the obtained signal light and the standard signal light have no specificity difference, the absence of the molecules to be detected is indicated;

if the obtained signal light has specificity difference with the standard signal light, the existence of the molecule to be detected is indicated;

wherein, the standard signal light is the signal light generated by FRET effect when the medium around the microcavity only contains the fluorescence acceptor substance preset by the system.

Advantageous effects

Compared with the prior art, the invention has the following advantages:

1. conventional methods for detecting biological enzymes generally require disruption of the normal physiological environment of the cell, such as observation of certain enzymatic activities of the cell, which typically requires a cell disruption process followed by addition of a reaction substrate to react to the catalytic effect by observing changes in substrate concentration. If the invention is adopted, the echo wall optical mode is combined with the FRET effect, the monitoring of the protein molecule activity under the condition of normal cell growth and metabolism can be realized, and the physiological characteristics of the enzyme closer to the natural state of the cell can be obtained by analyzing the spectral characteristics.

2. The core structure of the invention is in micron size, the used material is plastic polymer or quartz glass with stable performance, and the invention can be used repeatedly. The system can be more conveniently miniaturized and even made into a system on chip by combining the current mature light source and micro-nano lens design process.

3. Single-stranded DNA molecules and immunoprotein molecules are generally no larger than nanometer in size, beyond what can be observed with an optical microscope. Most of the previous methods for DNA hybridization and immunoassay are isotope labeling or molecular imprinting and imaging, and the microcavity sensing system can detect the binding or conformation change of molecules within a range of several micrometers, so that a novel method is provided for researching DNA molecular hybridization and immunoassay.

4. Combining whispering gallery modes with FRET has particular advantages. Although there have been many reports of detection using whispering gallery modes, the detection systems used are often relatively simple. The whispering gallery mode and FRET are combined, and the detected molecules are marked by proper fluorescent dye, so that the specific detection of the target molecules in a complex system can be realized.

In summary, the laser sensing detection system based on the whispering gallery mode and FRET principle has great potential and application in biomolecular dynamics, immunoassay, nucleic acid detection and protein-protein interaction. The research on the metabolic process of cell life has the extremely important position in biology, and the invention provides a new way for observing the process in real time.

Description of the drawings:

FIG. 1 is a schematic diagram of a laser sensing detection system based on whispering gallery modes and FRET principle in embodiment 1

FIG. 2 is a schematic diagram of a laser sensing detection system based on whispering gallery modes and FRET principle in embodiment 2

FIG. 3 is a schematic diagram of an embodiment 3 of a laser sensing detection system based on whispering gallery modes and FRET principle

FIG. 4 is a schematic diagram of a laser sensing detection system based on whispering gallery modes and FRET principle in embodiment 4

FIG. 5 is a schematic diagram of a laser sensing detection system based on whispering gallery modes and FRET principle in embodiment 5

FIG. 6 is a schematic diagram of an appearance of a resonant cavity sample in a laser sensing detection system based on whispering gallery modes and FRET principle

FIG. 7 is a detailed diagram of the FRET effect of the laser sensing detection system based on the whispering gallery mode and the FRET principle

FIG. 8 is a microscopic view of FRET effect of a laser sensing detection system based on whispering gallery mode and FRET principle

FIGS. 9a-d are schematic signal spectra of laser sensing detection system based on whispering gallery mode and FRET principle

Wherein, the laser source (11), the continuous attenuation sheet (12), the silver mirror (13), the resonant cavity sample (21), the dichroic mirror (33), the convex lens (34), the filter sheet (41), the convex lens (42) and the spectrometer (43)

Detailed Description

The present invention will be further described with reference to the following examples, but the present invention is not limited to the following examples.

Example 1

As shown in figure 1, a resonant cavity sample (21) adopts polymer beads (Bangs Laboratories, FS 07F) doped with dragon green dye with the average diameter of about 15 microns, a proper amount of raw solution of the beads is added into a prepared rhodamine (RhB) solution, after the mixture is fully mixed uniformly, a drop of reagent is dripped on a cover glass, another cover glass is covered on the cover glass, and the periphery of the cover glass is coated with nail polish for sealing treatment (figure 6). And fixing the sample on a glass slide after the sealed part is dried, thus preparing the sample to be measured which can be placed on a precise three-dimensional adjusting frame.

A continuous attenuation sheet (12) is arranged behind a laser source (11), after 90-degree reflection is carried out through a silver mirror (13), light beams are refracted by a 500nm low-pass high-reflection dichroic mirror (33) for 90 degrees, and the light beams are focused and collimated through a 40 multiplied first microscope objective (31) and are coupled to a resonant cavity sample (21) carried on a precise three-dimensional adjusting frame. The other side of the dichroic mirror (33) is provided with a camera (35). The rear end of the resonator sample (21) was fitted with a 60 x microscope objective (32), a 500nm long pass filter (41) and a convex lens (42) with focal length f =18.40mm, entering the probe of a spectrometer (43). The experimental device adopts a forward detection mode, and a convex lens (34) with the focal length f =100mm and a camera (35) are arranged on the other side of a dichroic mirror (33) to observe the position of the small ball in real time (figure 7).

During detection, a sample is vertically placed on a light path between two microscope objectives. The continuous attenuation sheet (12) is adjusted to adjust the light intensity of the light source to a lower intensity, the position of the sample is continuously adjusted, and whether the laser source (11) with the wavelength of 473nm is coupled on the small ball is observed through the CCD camera (35) at the other end until the light output by the small ball is displayed on the spectrometer to be strongest (figure 8). And then, the same small ball is injected with the increased laser coupling, and because the small ball has a strong echo wall effect, when 473nm laser is coupled into the small ball, a fluorescent substance dragon green in the ball can be excited to emit fluorescence with a wave band of 500-600 nm. When the intensity of the laser source reaches the threshold of a small sphere at 473nm, a cluster of laser peaks is emitted (FIG. 9 a), and FRET effect is generated in a fluorescent substance solution RhB with a proper concentration, so that the cluster of laser peaks is transferred to another wave bandf ₁ (transfer energy to longer bands) (fig. 9 b). On the basis, the molecules to be detected are added around the small ball, and when the distance between the molecules to be detected and the small ball is less than 10nm, the original FRET effect is disturbed, and a new FRET spectrum is formedf ₂ (FIG. 9 c). Because different molecules cause different disturbances to the sensing system, the generated spectral characteristics are different, and the existence and movement of the molecules can be specifically detected by comparing the spectral changes before and after the disturbances.

Example 2

As shown in fig. 2, the silver mirror (13) in embodiment 1 is removed, and the light exit angle of the laser light source (11) is adjusted to be perpendicular to the direction of the optical collimating system. Other execution methods are the same as those in embodiment 1, and the same detection effect can be achieved.

Example 3

As shown in fig. 3, the silver mirror (13) in embodiment 1 is removed, and the light exit angle of the laser light source (11) is adjusted to be perpendicular to the direction of the optical collimating system. The same detection effect can be achieved by replacing the 40 × first microscope objective lens (31) and the 60 × second microscope objective lens (32) with convex lenses and performing the same method as in example 1.

Example 4

As shown in fig. 3, the silver mirror (13) in embodiment 1 is removed, and the light exit angle of the laser light source (11) is adjusted to be perpendicular to the direction of the optical collimating system. Other implementation methods are the same as those in embodiment 1 except that the 40 × first microscope objective lens (31) and the 60 × second microscope objective lens (32) are replaced by convex lenses and the camera (35) is replaced by a white board, thereby achieving the same detection effect.

Example 5

As shown in fig. 5, the microfluidic channel (21) can precisely control the flow of the solution. The sensing system adopts dragon green dye-doped polymer beads (Bangs Laboratories, FS 07F) with the average diameter of about 15 mu m, firstly, a proper amount of a raw solution of the beads is added into a prepared rhodamine (RhB) solution to be uniformly mixed, and then, the mixed solution is injected into a microfluidic channel (21).

A continuous attenuation sheet (12) is arranged behind a laser source (11), light beams are refracted by a 500nm low-pass high-reflection dichroic mirror (33) for 90 degrees, and the light beams are focused and collimated through a 40 multiplied first microscope objective (31) and are coupled to a microfluidic channel (21) carried on a precise three-dimensional adjusting frame. The other side of the dichroic mirror (33) is provided with a camera (35). The rear end of the resonator sample (21) was fitted with a 60 x microscope objective (32), a 500nm long pass filter (41) and a convex lens (42) with focal length f =18.40mm, entering the probe (43) of the spectrometer. The experimental device adopts a forward detection mode, and a convex lens (34) with the focal length f =100mm and a camera (35) for imaging are arranged on the other side of a dichroic mirror (33) to observe the coupling effect of the small balls in real time.

The FRET effect spectrum f1 produced by the system was first recorded. On the basis, the molecules to be detected are added into the microfluidic channel, and when the distance between the molecules to be detected and the small ball is less than 10nm, the original FRET effect is disturbed, so that a new FRET spectrum f2 is formed. Comparison of the difference between f1 and f2 enables specific molecular detection.

Example 6

As shown in fig. 1, the resonant cavity module (2) in example 1 is slightly modified, and other devices are the same as those in example 1, so that the monitoring of the physiological activities of the cells can be realized. The concrete improvement is as follows: when the cells are cultured together with the pellets for a period of time, the pellets are phagocytized by the cells, and the cells are normally survived and metabolized. Adding a proper amount of cells phagocytizing the globules into the prepared rhodamine (RhB) solution, fully and uniformly mixing, then dripping a drop of reagent on a cover glass, covering the cover glass with another cover glass, and smearing nail polish on the periphery for sealing treatment. And fixing the sample on a glass slide after the sealed part is dried, thus manufacturing the resonant cavity sample (21) which can be placed on a precise three-dimensional adjusting frame.

During detection, a resonant cavity sample (21) is vertically placed on an optical path between two micro objectives. The continuous attenuation sheet (12) is adjusted to adjust the light intensity of the light source to a lower intensity, the position of the sample is continuously adjusted, and whether the laser source (11) with the wavelength of 473nm is coupled on the globule in the cell is observed through the CCD camera (35) at the other end until the light output by the globule is displayed to be strongest on the spectrograph. And then, the same small ball is injected with the increased laser coupling, and because the small ball has a strong echo wall effect, when 473nm laser is coupled into the small ball, a fluorescent substance dragon green in the ball can be excited to emit fluorescence with a wave band of 500-600 nm. A cluster of laser peaks is emitted after the 473nm laser source intensity reaches the threshold of the bead. In cytoplasm, the fluorescent acceptor substance RhB is also present due to absorption, so that the intracellular bead generates FRET effect, and the laser peak of the cluster is shifted to another band f1 (fig. 9 b). On the basis of the above, when the cell metabolizes, the molecules in the cytoplasm move around the bead continuously, and when the distance between the molecules and the bead is less than 10nm, the original FRET effect is disturbed, and a new FRET spectrum f2 is formed (FIG. 9 c). Because different molecules cause different disturbances on the sensing system, the generated spectral characteristics are different, and the physiological activities of the cells can be specifically detected by comparing the spectral changes before and after the disturbances.

Example 7

As shown in FIG. 5, the cavity module (2) in example 5 is slightly modified, and other devices are the same as those in example 5, so that the monitoring of the DNA single-strand hybridization activity can be realized. The concrete improvement is as follows: the single-stranded DNA is fixed on the surface of the small sphere by carrying out sulfhydrylation and covalent bonding reaction on the surface of the small sphere with the whispering gallery. The number of modified DNA can be judged by means of imaging tools such as a super-resolution confocal microscope and the like, conditions such as reaction concentration, time and the like are controlled, and modification of one or more chains is realized on the small ball. After fixing the DNA single chain outside the echo wall small ball, the single chain is placed into a microfluidic channel. And adjusting the laser light source and the coupling position pair to carry out excitation, wherein the fluid solution contains a certain concentration of substances capable of generating FRET effect, such as quantum dots. And measuring and recording the spectral information after the system is stabilized. When a solution containing the single-stranded DNA to be detected is slowly introduced, the anchor chain and the anchor chain on the bead are subjected to hybridization reaction. Because the double-stranded DNA is more compact and firmer in structure than the single-stranded DNA, the DNA after hybridization and combination can change in shape and direction outside the sphere, and further can interfere with the microenvironment outside the sphere of the small sphere. Because the conditions for FRET generation between the small ball and the liquid environment outside the ball are very sensitive, the interference caused by the change of the external environment can be visually displayed on the change of the spectrum. By using the detection means, the nucleic acid molecule detection of the specific sequence can be realized.

Claims (10)

1. A laser detection system based on resonant cavity and FRET effect is characterized in that: the system comprises a laser source module (1), a resonant cavity module (2), an optical collimation module (3) and a signal receiving module (4), wherein the laser source module (1) is used for providing a laser source and comprises a laser source (11) and a continuous attenuation sheet (12); the optical collimation module (3) is used for coupling the laser source to the resonant cavity module (2) and collecting signal light generated by the resonant cavity module (2) into the spectrometer, and comprises a first micro objective (31), a second micro objective (32), a dichroic mirror (33), a convex lens (34) and a camera (35), wherein the two focal lengths of the first micro objective and the second micro objective are coincident; the resonant cavity module (2) is used for generating optical resonance and FRET effect, and comprises a microcavity capable of generating optical resonance, a fluorescent acceptor substance capable of generating FRET effect around the microcavity, and a three-dimensional adjusting frame;

the microcavity is formed by polymer microspheres doped with fluorescent substances and acceptor fluorescent substances capable of generating FRET effect, a proper amount of fluorescent microspheres are added into another prepared fluorescent substance solution, a drop of reagent is dripped on a cover glass after the fluorescent microspheres are fully and uniformly mixed, the other cover glass is covered on the cover glass, the periphery of the cover glass is coated with nail polish for sealing treatment, and a sample is fixed on a glass slide after a sealed part is dried, so that the microcavity is manufactured;

The signal receiving module (4) is used for receiving, analyzing and storing signal light and comprises a filter plate (41), an aspheric lens (42) and a spectrometer (43); the output laser of laser source (11) has produced signal light through continuous attenuation piece (12) in proper order, dichroic mirror (33), first micro objective (31), resonant cavity module (2), signal light divide into two parts, partly signal light passes through second micro objective (32) in proper order, filter (41), aspheric lens (42), it receives to get into spectrum appearance (43) at last, analysis, storage, another part signal light passes through first micro objective (31) in proper order, dichroic mirror (33), convex lens (34) and camera (35), a coupling effect for real-time observation laser and resonant cavity, according to the image of real-time observation, realize best coupling with three-dimensional adjustment frame adjustment microcavity position.

2. A laser detection system based on resonator and FRET effects as claimed in claim 1, wherein: the two first micro objective lenses (31) and the second micro objective lenses (32) with coincident focal lengths are replaced by two convex lenses, or one micro objective lens and one convex lens.

3. A laser detection system based on resonator and FRET effects as claimed in claim 1, wherein: the camera (35) is a CCD or CMOS image sensor or a white board.

4. A laser detection system based on resonator and FRET effects as claimed in claim 1, wherein: the microcavity material is a material capable of forming optical resonance.

5. A laser detection system based on resonator and FRET effects as claimed in claim 1, wherein: the micro-cavity is in the form of a microsphere, a micro-disk, a micro-ring, a micro-tube and a micro-polygon, and the geometric radius of the micro-cavity is larger than the single wavelength of the laser source (11) and smaller than 1 mm.

6. A laser detection system based on resonator and FRET effects as claimed in claim 1, wherein: the micro-cavity is added with or without fluorescent substances.

7. A laser detection system based on resonator and FRET effects as claimed in claim 1, wherein: the fluorescent acceptor substance outside the cavity is in a gas state, a liquid state or a solid state, and the refractive index of the fluorescent acceptor substance is smaller than that in the resonant cavity; the fluorescent acceptor substance outside the cavity contains a plurality of fluorescent substances for the multiple FRET effect to occur.

8. A laser detection system based on resonator and FRET effects as claimed in claim 1, wherein: the resonant cavity module (2) is transformed into a microfluidic structure.

9. A laser detection system based on resonator and FRET effects as claimed in claim 1, wherein: the resonant frequency of the laser source module (1) is the same as the intrinsic resonant frequency of the resonant cavity module (2).

10. A method of detection using a laser system based on the resonator and FRET effects as claimed in any of claims 1-9, wherein: the laser source module (1) generates laser, the laser is coupled to the resonant cavity module (2) through the optical collimation module (3), the microcavity is excited to generate resonance, and then fluorescent acceptor substances around the microcavity are excited to generate FRET effect to generate signal light;

if the obtained signal light has no specificity difference with the standard signal light, the molecule to be detected does not exist;

if the obtained signal light has specificity difference with the standard signal light, the existence of the molecule to be detected is indicated;

wherein, the standard signal light is the signal light generated by FRET effect when the medium around the microcavity only contains the fluorescence acceptor substance preset by the system.

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