CN109990975A - Detection system, debugging system and sensor based on optical microcavity mechanical mode - Google Patents

Abstract

The embodiment of the invention discloses a kind of detection system based on optical microcavity mechanical mode, debugging system and sensors.The detection system includes laser beam emitting device, coupled waveguide, microcavity, photoelectric conversion device and data processing equipment；Wherein, coupled waveguide is connected between laser beam emitting device and photoelectric conversion device, for providing evanscent field, and when Critical Coupling occurs for the Whispering-gallery-mode of evanscent field and microcavity, by laser coupled to Whispering-gallery-mode, to excite the mechanical mode of microcavity；There is at least one contact point, for providing support force for coupled waveguide between microcavity and coupled waveguide；Data processing equipment, for after Critical Coupling occurs for the Whispering-gallery-mode of evanscent field and microcavity, determine the variable quantity of the mechanical mode of microcavity, and object under test information is determined by the variable quantity, realize that microcavity provides a degree of support for coupled waveguide, stable mechanical mode can be excited, so that experiment of pressing noise, obtains lower detectable limit.

Description

Detection system, debugging system and sensor based on optical microcavity mechanical mode

technical field

Embodiments of the present invention relate to optical sensing technology, and in particular, to a detection system, a debugging system and a sensor based on an optical microcavity mechanical mode.

Background technique

Optical sensing has a series of advantages such as non-physical contact, non-destructive, anti-electromagnetic interference, fast inductive transmission speed, diverse detection objects and high sensitivity, so it is important in chemical analysis, biological sensing, temperature detection, mechanical detection and other fields. research and practical application value.

At present, optical sensing can be realized through various structures, and the optical sensing principle is explained by taking the whispering gallery mode microcavity as an example. In the whispering gallery mode microcavity structure, the microcavity is placed in the evanescent field generated by the coupling waveguide. When the evanescent field is critically coupled with the whispering gallery mode, the laser can be coupled to the optical whispering gallery of the microcavity through the coupling waveguide. in mode. The optical pressure induces a change in the mechanical rigidity of the microcavity material, resulting in mechanical modes. Since the mechanical mode of the microcavity is related to the detuning of the laser relative to the optical whispering gallery mode and the effective mass of the microcavity, if the object to be tested causes the mode movement of the optical whispering gallery mode, or the effective mass of the microcavity changes, the microcavity will The mechanical mode of the test object changes, and the information of the object to be tested can be obtained through the change of the mechanical mode.

However, in order to ensure the coupling efficiency between the coupled waveguide and the microcavity, the distance between the two needs to be strictly controlled. In the related art, the fiber taper is usually used as the coupling waveguide. Since the size of the fiber taper is sub-micron, it is extremely susceptible to the influence of the surrounding environment, such as air flow or temperature change, etc. The distance changes, thereby affecting the detuning frequency between the laser and the whispering gallery modes, which in turn causes the mechanical modes of the microcavity to fluctuate, increasing the experimental noise.

SUMMARY OF THE INVENTION

The embodiments of the present invention provide a detection system, a debugging system and a sensor in an optical microcavity mechanical mode, which can improve the optical sensing scheme of the whispering gallery mode microcavity in the related art, reduce experimental noise, and obtain a smaller detection limit .

In a first aspect, an embodiment of the present invention provides a detection system based on an optical microcavity mechanical mode, including: a laser emission device, a coupling waveguide, a microcavity, a photoelectric conversion device, and a data processing device;

The laser emitting device is used for emitting laser light with a set wavelength, wherein the wavelength of the laser light is determined according to the detuning frequency between the laser light and the whispering gallery mode of the microcavity;

The coupling waveguide is connected between the laser emission device and the photoelectric conversion device to provide an evanescent field, and when the evanescent field is critically coupled with the whispering gallery mode of the microcavity, the coupling the laser to the whispering gallery mode to excite mechanical modes of the microcavity;

There is at least one contact point between the microcavity and the coupling waveguide for providing a supporting force for the coupling waveguide;

The photoelectric conversion device is electrically connected to the data processing device, and is used for converting the optical signal transmitted in the coupling waveguide into an electrical signal, and outputting the electrical signal to the data processing device;

The data processing device is configured to determine the amount of change of the mechanical mode of the microcavity according to the electrical signal after the evanescent field is critically coupled with the whispering gallery mode of the microcavity, and use the change Quantity determines the information of the object to be measured.

In a second aspect, an embodiment of the present invention further provides a debugging system for a detection system based on an optical microcavity mechanical mode, including a spectrometer, a microcavity position adjustment device, and the detection system based on the optical microcavity mechanical mode described in the first aspect. ;

The spectrometer is connected between the coupling waveguide and the photoelectric conversion device through an optical splitter, for determining and displaying the coupling waveguide before the evanescent field is critically coupled with the whispering gallery mode of the microcavity The spectrum of the laser transmitted inside, if it is determined according to the spectrum that there are lasers with at least two wavelengths in the coupling waveguide, output a prompt message of reducing power;

The microcavity position adjustment device is detachably connected to the microcavity, and is electrically connected to the data processing device, and is used for performing a critical coupling between the evanescent field and the whispering gallery mode of the microcavity according to the The electrical signal determines an adjustment parameter of the microcavity, and adjusts the relative position of the microcavity and the coupling waveguide according to the adjustment parameter.

In a third aspect, an embodiment of the present invention further provides a sensor, including the detection system based on the optical microcavity mechanical mode described in the first aspect.

The embodiment of the present invention provides a detection system based on the optical microcavity mechanical mode. By adjusting the relative position between the coupling waveguide and the microcavity, when the evanescent field of the coupling waveguide and the whispering gallery mode of the microcavity are critically coupled, all There is at least one contact point between the microcavity and the coupling waveguide, so that the microcavity provides a certain degree of support for the coupling waveguide, which can excite a stable mechanical mode, thereby suppressing experimental noise and obtaining a lower detection limit. The technical solution of the embodiment of the present invention can avoid the problem that the distance between the coupling waveguide and the microcavity is not constant due to the influence of environmental factors, which leads to the instability of the detuning frequency between the laser and the whispering gallery mode, thereby increasing the experimental noise. .

Description of drawings

1 provides a block diagram of a detection system based on an optical microcavity mechanical mode in a conventional technology for an embodiment of the present invention;

2 is a block diagram of a detection system based on an optical microcavity mechanical mode provided by an embodiment of the present invention;

3 is a graph showing the variation of the center frequency of the mechanical frequency of the microcavity with time in a measurement process provided by an embodiment of the present invention;

FIG. 4 is a block diagram of a debugging system of a detection system based on an optical microcavity mechanical mode according to an embodiment of the present invention.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention. In addition, it should be noted that, for the convenience of description, the drawings only show some but not all structures related to the present invention.

For ease of understanding, various terms appearing in the embodiments of the present invention are explained.

Microcavity refers to an optical resonant cavity with a high quality factor and a size in the micrometer scale. The current shapes of microcavities mainly include microrings, microspheres, microdisks, micropillars, microcore rings, deformable cavities, microbubbles, Fa-Pert cavities, and photonic crystal microcavities. Among them, the microcavity based on the whispering gallery mode is the most representative. Due to the high quality factor of the microcavity, for example, the quality factor can reach 10 ⁸ , it is possible to excite the mechanical modes of the microcavity at lower power.

Whispering gallery mode, originated from the field of acoustics, its principle is that sound waves can be continuously reflected on curved and smooth walls with little loss, so the sound can travel a long distance along the wall, this effect is called the whispering cloister mode ( Whispering Gallery Mode, WGM), that is, the whispering gallery mode. Similar to the reflection of sound waves on a wall, when light is incident from an optically denser to an optically sparser medium and the incident angle is large enough, total reflection can also occur on the surfaces of the two mediums. Whispering Bar Mode. Within the boundary of the closed cavity, light can always be localized in a stable traveling wave transmission mode inside the cavity.

Coupling waveguide, the medium through which light waves are guided to travel. For example, the coupling waveguide can be a fiber taper. The fiber taper is an optical waveguide that draws the diameter of an ordinary fiber to a sub-micron level through a hydrogen-oxygen flame. There is an evanescent field with a range of several hundred nanometers outside the fiber cone, and the microcavity is placed in the evanescent field. When the waveguide mode in the fiber cone and the whispering gallery mode of the microcavity meet the phase matching condition, the laser coupling of the fiber cone into the microcavity. Among them, we refer to the electromagnetic field type that can be transmitted in the waveguide as the mode of the waveguide. By adjusting the distance between the fiber cone and the microcavity, the loss of the microcavity is equal to the coupling strength, and the critical coupling is achieved; the optical pressure generated by the whispering gallery mode causes the mechanical rigidity of the material to change and excites the mechanical mode of the microcavity.

FIG. 1 provides a block diagram of a detection system based on the mechanical mode of an optical microcavity in a conventional technology according to an embodiment of the present invention. As shown in FIG. 1 , the detection system includes a microcavity 110, a fiber taper 120, a tunable laser 130, a photoelectric Detector 140 and Spectrum Analyzer 150. In order to achieve critical coupling, the fiber cone is fixed on the equatorial plane of the microcavity and has a certain distance from the microcavity. However, the size of the fiber cone is sub-micron, and it is easily disturbed by the surrounding environment, so that the distance between the fiber cone and the microcavity is not a constant, but changes with the surrounding environment, affecting the laser and the whispering gallery. The frequency of detuning between modes, which in turn affects the frequency, intensity, and linewidth of the mechanical modes. Due to the instability of the frequency, intensity and linewidth of the mechanical mode, the experimental noise during the measurement process is increased, that is, the jitter generated by the influence of the optical fiber cone by the surrounding environment increases the experimental noise. When the change of the mechanical mode caused by the DUT is small, the sensing signal is covered by the experimental noise, and the sensing signal cannot be distinguished from the experimental noise.

In order to solve the problem of the increase of experimental noise in the related art, thereby affecting the detection limit, an embodiment of the present invention provides a detection system based on an optical microcavity mechanical mode.

FIG. 2 is a block diagram of a detection system based on the mechanical mode of an optical microcavity provided by an embodiment of the present invention. This embodiment can be applied to the case of detecting the information of a small object to be tested through the change of the mechanical mode of the optical microcavity. For example, the detection system based on the optical microcavity mechanical mode can be applied as a sensor, that is, a sensor can be integrated with the above detection system based on the optical microcavity mechanical mode.

As shown in FIG. 2 , the detection system based on the optical microcavity mechanical mode includes: a laser emission device 210 , a coupling waveguide 220 , a microcavity 230 , a photoelectric conversion device 240 and a data processing device 250 .

The laser emitting device 210 is used for emitting laser light with a set wavelength, wherein the wavelength of the laser light is determined according to the detuning frequency between the laser light and the whispering gallery mode of the microcavity. Since the mechanical mode of the microcavity is related to the detuning of the laser with respect to the optical whispering gallery mode. The trough of the transmission spectrum can be detected in advance with tools such as an oscilloscope, and the frequency at the trough can be determined. By controlling the frequency sweep of the laser emitting device 210, the wavelength corresponding to the frequency to be locked is determined according to the changing trend of the frequency at the valley. The wavelength of the laser emitting device 210 is fixed at the wavelength value corresponding to the set detuning frequency by means of thermal locking, so that the laser emitted by the laser emitting device 210 is within the frequency range of the whispering gallery mode, and by stabilizing the detuning frequency, the The purpose of suppressing experimental noise to a certain extent. The laser emitting device 210 may be a tunable laser transmitter.

The coupling waveguide 220 is connected between the laser emitting device 210 and the photoelectric conversion device 240 for providing an evanescent field, and when the evanescent field is critically coupled with the whispering gallery mode of the microcavity 230, the laser is coupled to the whispering gallery mode, to excite the mechanical modes of the microcavity 230 . Wherein, when the loss of the microcavity 230 is equal to the coupling strength, and the evanescent field and the whispering gallery mode of the microcavity 230 satisfy the phase matching condition, the evanescent field and the whispering gallery mode are critically coupled. It should be noted that the phase matching condition may be that the phase of the laser in the evanescent field is equal to the phase of the laser in the microcavity 230 . It can be understood that, the phase matching condition may also be other phase relationships to achieve critical coupling between the evanescent field and the whispering gallery mode, which is not specifically limited in the embodiment of the present invention. When the evanescent field is critically coupled with the whispering gallery mode of the microcavity, more laser light is coupled to the microcavity. Due to the higher quality factor of the microcavity, the mechanical mode of the microcavity can be excited with less power. Wherein, the coupling waveguide 220 may be an optical fiber cone or the like, and the microcavity may be an optical microcavity with rotational axis symmetry.

There is at least one contact point between the microcavity 230 and the coupling waveguide 220 for providing a supporting force for the coupling waveguide 220 . By contacting the microcavity 230 with the coupling waveguide 220, the microcavity 230 can provide a supporting force for the coupling waveguide 220, so that the coupling waveguide 220 with a diameter of sub-micron level or smaller can resist the interference of the external environment, thereby exciting a stable mechanical mode , which can effectively suppress the experimental noise. FIG. 3 is a graph showing the variation of the center frequency of the mechanical frequency of the microcavity with time in a measurement process according to an embodiment of the present invention. As shown in FIG. 3 , the abscissa is time, the ordinate is the center frequency of the mechanical frequency, 31 represents the variation curve of the center frequency of the mechanical frequency in the conventional technology with time, and 32 represents the center frequency of the mechanical frequency in the embodiment of the present invention. change curve. Measuring the stability of the mechanical frequency within 5 minutes, it is concluded that the experimental noise of the mechanical frequency is suppressed by three orders of magnitude.

It should be noted that by locking the frequency of the laser at a fixed detuning frequency of the whispering gallery mode, combined with the way of controlling the contact between the microcavity 230 and the coupling waveguide 220, the experimental noise is suppressed. During the measurement, the small mechanical mode changes caused by the object to be measured can also be read from the experimental noise, resulting in a smaller detection limit.

The photoelectric conversion device 240 is electrically connected to the data processing device 250 for converting the optical signal transmitted in the coupling waveguide 220 into an electrical signal, and outputting the electrical signal to the data processing device 250 . For example, the photoelectric conversion device 240 may be a photodetector.

The data processing device 250 is configured to determine the variation of the mechanical mode of the microcavity 230 according to the electrical signal after the evanescent field is critically coupled with the whispering gallery mode of the microcavity 230, and determine the object information by the variation. For example, the data processing device 250 may include a spectrum analysis module. For another example, the data processing device 250 may include a data acquisition card and a computing module. When there is no object to be measured, after the evanescent field is critically coupled with the whispering gallery mode of the microcavity 230 , the laser is coupled to the optical whispering gallery mode of the microcavity 230 to a great extent. The optical pressure induces a change in the mechanical rigidity of the microcavity material, resulting in mechanical modes. When the object under test approaches the microcavity 230, the object under test causes a mode movement of the optical whispering gallery mode. If the object to be measured is attached to the surface of the microcavity, the effective mass of the microcavity 230 will change. When the object to be tested causes the mode movement of the optical whispering gallery mode, or the effective mass of the microcavity 230 changes, the mechanical mode of the microcavity 230 changes, and the change in the mechanical mode of the microcavity 230 is called a sensing signal. For example, the change in the mechanical mode may be a change in the vibration frequency, vibration line width or vibration intensity of the microcavity 230 . The sensing signal representing the change of the mechanical mode is collected by the data acquisition card, and the data acquisition card sends the sensing signal to the computing module. The calculation module determines the variation of the vibration frequency and/or the vibration line width and/or the vibration intensity of the microcavity 230 from the sensing signal, and calculates the information of the object to be measured based on the variation. The information of the object to be measured includes the number, size, mass, refractive index or concentration of the object to be measured, and the like. In addition, the data acquisition card collects the transmission spectrum in real time, which is convenient for the calculation module to analyze whether the detuning of the laser is stable. When the object to be tested enters the evanescent field of the whispering gallery mode, the whispering gallery mode changes (for example, frequency shift, splitting or broadening). , so as to obtain the change of mechanical frequency, which is used as an optical sensing signal to detect the object to be tested.

In the technical solution of this embodiment, by adjusting the relative position between the coupling waveguide and the microcavity, when the evanescent field of the coupling waveguide and the whispering gallery mode of the microcavity are critically coupled, the gap between the microcavity and the coupling waveguide is There is at least one point of contact, realizing that the microcavity provides a certain degree of support for the coupled waveguide, which can excite stable mechanical modes, thereby suppressing experimental noise and obtaining a lower detection limit. The technical solution of the embodiment of the present invention can avoid the problem that the distance between the coupling waveguide and the microcavity is not constant due to the influence of environmental factors, which leads to the instability of the detuning frequency between the laser and the whispering gallery mode, thereby increasing the experimental noise. .

Optionally, in some embodiments, the data processing apparatus may further include a data acquisition card, a calculation module and a spectrum analysis module. Among them, the spectrum analysis module can decompose the measured signal into discrete frequency components through Fourier operation. In the embodiment of the present invention, the spectrum analysis module receives the electrical signal, determines the transmission spectrum of the laser transmitted in the coupled waveguide according to the electrical signal; collects the mechanical vibration signal in the transmission spectrum, and determines the object information according to the mechanical vibration signal. For example, when the object to be measured adheres to the surface of the microcavity, both the detuning frequency of the laser and the effective mass of the microcavity change, resulting in the mechanical frequency of the microcavity (for example, the center frequency, center intensity or linewidth of the transmission spectrum, etc. ) changes. The spectrum analysis module collects mechanical vibration signals (eg, mechanical frequency variation parameters) in the transmission spectrum, and detects the object to be measured according to the mechanical vibration signal to obtain first information of the object to be measured. In addition, the sensor signal representing the change of the mechanical mode is collected by the data acquisition card, and the change amount of the vibration frequency and/or vibration intensity of the microcavity is determined from the sensor signal by the calculation module, and the object to be measured is calculated based on the change amount. the second information. If the deviation between the first information and the second information is less than or equal to the set error threshold, the first information or the second information is used as the information of the object to be measured. If the deviation between the first information and the second information is greater than the set error threshold, a measurement error is prompted. The advantage of this setting is that the first information of the object to be measured is determined through the spectrum analysis module, the second information of the object to be measured is determined through the data acquisition card combined with the calculation module, and the measurement results are compared by comparing the first information and the second information. Validation improves measurement accuracy.

FIG. 4 is a block diagram of a debugging system of a detection system based on an optical microcavity mechanical mode according to an embodiment of the present invention. As shown in FIG. 4 , the debugging system includes a spectrometer 407 , a microcavity position adjustment device 414 and a detection system based on an optical microcavity mechanical mode.

The laser light emitted by the laser emitting device 401 is transmitted to the coupling waveguide 440, and the spectrometer 407 is connected between the coupling waveguide 440 and the photoelectric conversion device 408 through the beam splitter 406, for the evanescent field and the whispering gallery mode of the microcavity 405 before critical coupling occurs , determine and display the spectrum of the laser light transmitted in the coupling waveguide 404 , if it is determined according to the spectrum that there are at least two wavelengths of laser light in the coupling waveguide 404 , output a prompt message of lowering the power. The laser light transmitted in the coupling waveguide 404 is divided into two beams by the beam splitter 406 , wherein one laser beam enters the photoelectric conversion device 408 , and the other laser beam enters the spectrometer 407 . The spectrometer 407 receives the laser light transmitted by the coupling waveguide 404, and determines the spectrum corresponding to the transmission spectrum of the laser light. According to the spectrum, it can be determined whether a nonlinear phenomenon is generated in the current coupling waveguide 404, for example, Raman laser is generated. Whether a nonlinear phenomenon occurs can be determined by determining that the spectrum contains lasers with several wavelengths. If a nonlinear phenomenon occurs, multiple lasers will appear in the spectrum. If it is determined that a nonlinear phenomenon has occurred, a prompt message of reducing the power of the laser is output to avoid the generation of the nonlinear phenomenon in the microcavity. Since the non-linear phenomenon occurs or the beat frequency is generated, the mechanical frequency as the sensing signal is disturbed. Therefore, the non-linear phenomenon needs to be avoided.

The microcavity position adjustment device 414 is detachably connected to the microcavity 405, and is electrically connected to the data processing device 409, for determining according to the electrical signal before the evanescent field critically couples with the whispering gallery mode of the microcavity 405 Adjustment parameters of the microcavity, and adjust the relative position of the microcavity and the coupling waveguide according to the adjustment parameters.

Since the transmission spectrum of the fiber taper in steady state can be expressed as:

Among them, T is the transmittance when the detuning frequency is Δω, k ₁ is the coupling strength, and k ₀ is the loss of the microcavity. When k ₀ = k ₁ , the transmittance of the fiber cone is zero, and the echo of the microcavity is zero. The wall modes are critically coupled with the evanescent field of the fiber taper.

The microcavity position adjustment device can obtain the spectrum of the transmission spectrum according to the electrical signal corresponding to the transmission spectrum in the coupled waveguide, and determine the power of the trough and the trough point in the spectrum. The microcavity is controlled to move to the coupling waveguide by a first set distance. As the distance changes, the coupling state between the evanescent field and the whispering gallery mode also changes, resulting in a change in the spectrum of the laser light in the coupled waveguide. The trough and the power of the trough in the current spectrum are determined by the data processing device. If the power of the wave valley decreases, the microcavity is controlled to move to the coupling waveguide by a second set distance in the same direction (which may be the same as or different from the first set distance, for example, as the distance between the microcavity and the coupling waveguide decreases, the The set distance gradually decreases). Again, the trough and the power of the trough in the current spectrum are determined by the data processing device. If the power of the valley continues to decrease, the same operation as above is performed. If the power of the wave trough increases, the microcavity is controlled to move toward the coupling waveguide in the opposite direction to set a third distance, so that the difference between the power at the wave trough of the spectrum and zero is less than the set value. When the difference between the power at the valley of the spectrum and zero is less than the set value, the transmittance is considered to be zero, and it is determined that the evanescent field is critically coupled with the whispering gallery mode of the microcavity. Optionally, in the evanescent field When critical coupling occurs with the whispering gallery mode of the microcavity, the position of the microcavity is fixed, and a debugging end message is prompted.

It should be noted that, in the detection system based on the optical microcavity, by collecting the mechanical vibration signal (for example, the mechanical frequency change parameter) in the transmission spectrum by the spectrum analyzer 411, the detected object information is detected with the data processing device. The method of comparing the information of the object to be measured by the data processing device verifies whether the information of the object to be measured determined by the data processing device based on the change of the mechanical frequency is accurate.

In the technical solution of this embodiment, the spectrum of the transmission spectrum is obtained by a spectrometer, and based on the spectrum, it is judged whether a nonlinear phenomenon occurs in the microcavity, and according to the judgment result, it is indicated whether to reduce the power of the laser, so as to avoid the interference of the mechanical frequency due to the generation of the beat frequency from the source. The problem can reduce experimental noise. In addition, the relative position between the microcavity and the coupling waveguide is adjusted based on the transmission spectrum of the laser light transmitted in the coupling waveguide by the microcavity position adjustment device, so as to realize the critical coupling between the evanescent field and the whispering gallery mode of the microcavity, The microcavity is in contact with the coupling waveguide to ensure stable coupling conditions, thereby ensuring excitation of stable mechanical modes, thereby suppressing experimental noise.

In some embodiments, the microcavity position adjustment device includes a three-dimensional nanotranslation stage 413 and a stage controller 412 . The workbench controller 412 is electrically connected with the data processing device 409, and is used to obtain the electrical signal in the data processing device, determine the transmission spectrum of the laser light according to the electrical signal, and detect the relationship between the evanescent field and the whispering gallery mode of the microcavity according to the transmission spectrum. The coupling state is determined, and the adjustment parameters of the microcavity are determined according to the coupling state, and an adjustment command is output to the three-dimensional nanotranslation stage 413 according to the adjustment parameters. The three-dimensional nanotranslation stage 413 is electrically connected to the stage controller 412 for adjusting the relative positions of the microcavity 405 and the coupling waveguide 404 according to the adjustment instruction, so that the evanescent field and the whispering gallery mode of the microcavity critically couple. Since the whispering gallery mode is attenuated in both the radial and azimuthal directions, the position of the microcavity is adjusted by the three-dimensional nanotranslation console 413 so that the fiber cone is separated from the equatorial plane of the microcavity, and a position can be found when the fiber cone stops at the equatorial plane of the microcavity. When the surface of the microcavity is connected, the two can still achieve critical coupling. Since the fiber taper is supported by the microcavity, the influence of the external environment is reduced and the experimental noise is suppressed.

For example, the stage controller obtains the spectrum of the transmission spectrum according to the electrical signal corresponding to the transmission spectrum in the coupled waveguide, and determines the power of the trough and the trough point in the spectrum. According to the power at the valley point, it is determined that the coupled waveguide and the microcavity are in an under-coupled state, and an adjustment command for moving the first set distance is output to the 3D nanotranslation stage, and the 3D nanotranslation stage is used to control the microcavity to move to the coupled waveguide by the first set distance. Then, the trough and the power of the trough in the current spectrum are determined by the stage controller. If the power of the valley decreases, the output controls the microcavity to move toward the coupling waveguide a second set distance in the same direction (which can be the same as or different from the first set distance, for example, it can be as the distance between the microcavity and the coupling waveguide decreases, The set distance gradually decreases) adjustment command to the three-dimensional nano-translation stage to adjust the relative position between the microcavity and the coupled waveguide. The troughs and trough powers in the current spectrum are again determined by the stage controller. If the power of the valley continues to decrease, the same operation as above is performed. If the power of the trough increases, an adjustment command to control the microcavity to move to the coupling waveguide to set a third distance in the opposite direction is output, so that the difference between the power at the trough of the spectrum and zero is less than the set value. When the difference between the power at the valley of the spectrum and zero is less than the set value, the transmittance is considered to be zero, and it is determined that the evanescent field is critically coupled with the whispering gallery mode of the microcavity. Taking the coupling waveguide as an optical fiber cone as an example, the relative position of the microcavity and the fiber cone is adjusted by a three-dimensional nano-translation console, so that the loss of the microcavity is equal to the coupling strength, and the evanescent field and the whispering gallery mode of the microcavity satisfy the phase matching condition , at this time, the evanescent field is critically coupled with the whispering gallery mode, and the laser is coupled into the microcavity.

In other embodiments, the debugging system further includes an oscilloscope 410 , and the microcavity position adjustment device can be electrically connected to the oscilloscope 410 . The oscilloscope 410 is electrically connected to the photoelectric conversion device 408 for receiving an electrical signal corresponding to the laser light transmitted in the coupling waveguide 404 before the evanescent field is critically coupled with the whispering gallery mode of the microcavity. The oscilloscope 410 determines and displays the transmission spectrum of the laser light in the coupling waveguide 404 according to the electrical signal. In addition, the oscilloscope 410 outputs the transmission spectrum to the microcavity position adjustment device 414 . For example, the oscilloscope 410 is electrically connected to the stage controller 412 to output the transmission spectrum to the stage controller 412, and the stage controller 412 and the three-dimensional nanotranslation stage 413 adjust the manner in which the relative position between the microcavity and the coupled waveguide is adjusted The same as before, and will not be repeated here.

Optionally, the debugging system further includes a variable optical attenuator 402 . The variable optical attenuator 402 is connected to the laser emitting device 401 through an optical fiber, and is used to receive the laser light emitted by the laser emitting device before the evanescent field is critically coupled with the whispering gallery mode of the microcavity 405, and according to the spectral pair in the spectrometer 407. The power of the laser is adjusted to avoid nonlinearities in the microcavity.

Optionally, the debugging system further includes a polarization controller 403 . The polarization controller 403 is connected to the variable optical attenuator 402 through an optical fiber, and is electrically connected to the oscilloscope 410 for adjusting the polarization state of the laser light emitted by the laser emitting device 401 based on the transmission spectrum of the oscilloscope 410, so as to adjust the bias state by adjusting the polarization state. Reduce the probability of nonlinear phenomena in the microcavity.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims . In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb "comprise" and its conjugations does not exclude the presence of elements or steps other than those recited in a claim. The articles "a" or "an" preceding an element do not exclude the presence of a plurality of such elements. The present invention may be implemented by hardware comprising several distinct elements, as well as by suitably programmed computers. In a device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

Although various aspects of the invention are presented in independent claims, other aspects of the invention include combinations of features from the described embodiments and/or dependent claims having features of the independent claims, and not just claims combinations specified in .

Note that the above are only preferred embodiments of the present invention and applied technical principles. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and can also include more other equivalent embodiments without departing from the concept of the present invention. The scope is determined by the scope of the appended claims.

Claims (9)

1. A detection system based on an optical microcavity mechanical mode, comprising: a laser emission device, a coupling waveguide, a microcavity, a photoelectric conversion device and a data processing device; The laser emitting device is used for emitting laser light with a set wavelength, wherein the wavelength of the laser light is determined according to the detuning frequency between the laser light and the whispering gallery mode of the microcavity; The coupling waveguide is connected between the laser emission device and the photoelectric conversion device to provide an evanescent field, and when the evanescent field is critically coupled with the whispering gallery mode of the microcavity, the coupling the laser to the whispering gallery mode to excite mechanical modes of the microcavity; There is at least one contact point between the microcavity and the coupling waveguide for providing a supporting force for the coupling waveguide; The photoelectric conversion device is electrically connected to the data processing device, and is used for converting the optical signal transmitted in the coupling waveguide into an electrical signal, and outputting the electrical signal to the data processing device; The data processing device is configured to determine the amount of change of the mechanical mode of the microcavity according to the electrical signal after the evanescent field is critically coupled with the whispering gallery mode of the microcavity, and use the change Quantity determines the information of the object to be measured. 2. The detection system according to claim 1, wherein the data processing device comprises a data acquisition card and a computing module; The data acquisition card is electrically connected to the computing module, and is used for collecting the electrical signal and sending the electrical signal to the computing module; The calculation module is configured to determine the transmission spectrum of the laser light transmitted in the coupling waveguide according to the electrical signal, and after the evanescent field is critically coupled with the whispering gallery mode of the microcavity, according to the transmission The spectrum acquires the variation of the mechanical mode of the microcavity, and determines the information of the object to be measured by the variation. 3. The detection system according to claim 2, wherein the data processing device further comprises a spectrum analysis module; the spectrum analysis module, configured to receive the electrical signal, and determine the transmission spectrum of the laser light transmitted in the coupling waveguide according to the electrical signal; The mechanical vibration signal in the transmission spectrum is acquired, and the object information to be measured is determined according to the mechanical vibration signal. 4. A debugging system for a detection system based on an optical microcavity mechanical mode, characterized in that it comprises a spectrometer, a microcavity position adjustment device, and the detection based on the optical microcavity mechanical mode according to any one of claims 1-3 system; The spectrometer is connected between the coupling waveguide and the photoelectric conversion device through an optical splitter, for determining and displaying the coupling waveguide before the evanescent field is critically coupled with the whispering gallery mode of the microcavity The spectrum of the laser transmitted inside, if it is determined according to the spectrum that there are lasers with at least two wavelengths in the coupling waveguide, output a prompt message of reducing power; The microcavity position adjustment device is detachably connected to the microcavity, and is electrically connected to the data processing device, and is used for performing a critical coupling between the evanescent field and the whispering gallery mode of the microcavity according to the The electrical signal determines an adjustment parameter of the microcavity, and adjusts the relative position of the microcavity and the coupling waveguide according to the adjustment parameter. 5. The debugging system according to claim 4, further comprising: a variable optical attenuator; The variable optical attenuator is connected to the laser emitting device through an optical fiber, and is used to receive the laser light emitted by the laser emitting device before the evanescent field is critically coupled with the whispering gallery mode of the microcavity, and The power of the laser is adjusted according to the spectrum in the spectrometer. 6. The debugging system according to claim 4, wherein the microcavity position adjustment device comprises a three-dimensional nano-translation workbench and a workbench controller; The workbench controller is configured to acquire the electrical signal in the data processing device, determine the transmission spectrum of the laser light according to the electrical signal, and detect the relationship between the evanescent field and the microcavity according to the transmission spectrum. the coupling state of the whispering gallery mode, and determining the adjustment parameters of the microcavity according to the coupling state, and outputting adjustment instructions to the three-dimensional nano-translation stage according to the adjustment parameters; The three-dimensional nano-translation stage is electrically connected to the stage controller, and is used to adjust the relative position of the microcavity and the coupling waveguide according to the adjustment instruction, so that the evanescent field and the microcavity critical coupling of the whispering gallery modes occurs. 7. The debugging system according to claim 4, further comprising an oscilloscope; The oscilloscope is electrically connected to the photoelectric conversion device and the microcavity position adjustment device, respectively, for determining and outputting the coupled waveguide before the evanescent field is critically coupled with the whispering gallery mode of the microcavity The transmission spectrum of the laser light transmitted within is given to the microcavity position adjustment device. 8. The debugging system according to claim 7, further comprising a polarization controller; The polarization controller is connected to the variable optical attenuator through an optical fiber, and is electrically connected to the oscilloscope, for adjusting the polarization state of the laser light emitted by the laser emitting device based on the transmission spectrum of the oscilloscope. 9 . A sensor, characterized in that it comprises the detection system based on the optical microcavity mechanical mode according to any one of the above claims 1 to 3 . 10 .