A method for obtaining high-frequency stability sidebands by resonantly exciting microresonators

Abstract

The present invention relates to a method for obtaining high-frequency stability sidebands by resonantly exciting a microresonator, and belongs to the field of micro-electromechanical system control, including: measuring the frequency responses of the second-order bending mode and the first-order torsional mode of a microcantilever beam resonator under a detection voltage to determine the eigenfrequency; pumping at the first-order torsional mode to induce nonlinear modal coupling between the second-order bending mode and the first-order torsional mode to obtain a narrow linewidth sideband; using a phase-locked amplifier to measure the frequency stability of the microcantilever beam resonator to obtain a high-frequency stability sideband. The present invention only uses a signal generator to output a pump signal to modulate the microresonator to obtain a narrow linewidth high-frequency stability sideband, and has a strong principle and is easy to operate. The present invention obtains a narrow linewidth high-frequency stability sideband of a microcantilever beam resonator in a single cantilever beam system for the first time, which is of great significance for improving the frequency stability of the microcantilever beam resonator and studying the nonlinear dynamic behavior of the resonator.

Description

Technical Field

[0001] The invention relates to a method for obtaining a high-frequency stability sideband by a resonantly excited micro-resonator, and belongs to the technical field of micro-electromechanical system control. Background Art

[0002] The concept of micro-electromechanical system (MEMS) was proposed in the 1950s. It is a micro-integrated system that uses integrated circuit manufacturing technology and micro-machining technology to manufacture microstructures, micro-sensors, control processing circuits and even interfaces, communications and power supplies on one or more chips. It is an industrial technology that combines microcircuits and micro-machines on chips according to functional requirements. It is a combination of microelectronics technology and mechanical engineering. MEMS has developed with the development of semiconductor integrated circuit micro-machining technology and ultra-precision machining technology. Because of its advantages such as low cost, fast response, high precision and mass production, it is widely used in high-tech industries such as sensors, communications, and biomedicine.

[0003] As an important component of MEMS, microresonators are designed into various structures to meet the needs of different fields, such as single-ended cantilever beams, double-ended beams, microring / microdisk resonators, and comb-shaped resonators. As the size of MEMS devices approaches the micron and nanometer levels, it is very important to develop technologies to improve the frequency stability of MEMS resonators. At present, there are mainly the following methods to improve the frequency stability of MEMS resonators:

[0004] 1. Antisymmetric vibration

[0005] Antisymmetric vibration refers to the opposite vibration phase between different modes in some dual-mode or multi-mode resonators. This vibration mode can reduce the frequency aliasing caused by mode coupling, thereby improving frequency stability. Jianshu Du et al. improved the frequency stability of the micromechanical DETF oscillator by absorbing the energy of antisymmetric vibration, and the short-term frequency stability was improved from 378 ppb to 202 ppb. The disadvantage of antisymmetric vibration is that in some cases, strong mode competition may occur, which may reduce the purity of the signal spectrum and affect the frequency stability.

[0006] 2. Modal Positioning

[0007] Modal localization refers to the process of exciting specific vibration modes and suppressing other modes in a multimode resonator through specific design or control methods. This can improve the signal purity of a specific mode, reduce mode competition, and thus improve frequency stability. Mingying Tang et al. achieved single-mode lasing and modal localization in a square microresonator by adjusting the output waveguide, thereby avoiding modal hopping and improving frequency stability. The disadvantage of modal localization is that it may only be applicable to specific application scenarios and may require complex identification and control techniques to achieve.

[0008] 3. Synchronous technology

[0009] Synchronization technology can improve frequency stability in microresonators. Through synchronization technology, multiple resonators can be locked to a common frequency, reducing frequency fluctuations caused by individual differences. Xueyong Wei et al. synchronized two disk resonators by electrical signal injection, thereby reducing the Allan deviation of their frequency from 19.3 ppb to 5.17 ppb and improving short-term frequency stability. The disadvantage of synchronization is that it may be affected by synchronization interference and excitation forces, which may destroy the stability of the oscillator and cause frequency tracking when the frequency difference is less than the synchronization bandwidth.

[0010] For microresonators, it is very important to reduce dissipation to achieve narrow linewidth of modes and improve the frequency stability of MEMS resonators. Summary of the invention

[0011] In view of the shortcomings of the prior art, the present invention provides a method for obtaining a high-frequency stability sideband by resonantly exciting a microresonator. By simply using a signal generator to output a pump signal to modulate the microresonator, a narrow linewidth and high-frequency stability sideband can be obtained. The method has strong principle and is easy to operate.

[0012] The present invention adopts the following technical solution:

[0013] A method for obtaining high-frequency stability sidebands by resonantly exciting a microresonator comprises the following steps:

[0014] S1: Measure the frequency response of the second-order bending mode and the first-order torsion mode of the microcantilever beam resonator under the detection voltage to determine the eigenfrequency;

[0015] S2: Pumping at the first-order torsional mode induces nonlinear mode coupling between the second-order bending mode and the first-order torsional mode, and obtains a narrow linewidth sideband;

[0016] S3: The frequency stability of the microcantilever resonator was measured using a phase-locked loop (PLL) amplifier, and the sideband with high frequency stability was obtained;

[0017] The implementation process of step S2 is:

[0018] S21: The signal generator output frequency is f p The pump signal is related to the eigenfrequency of the first-order torsional mode. f t Same, 332.19 kHz, and gradually increase the pump voltage V pump , V pump The size of is gradually increased from 250mV to 350mV, and this pump signal is applied to the cantilever beam of the microcantilever beam resonator through the piezoelectric resonator;

[0019] S22: A detection voltage signal is output by a phase-locked amplifier and applied to the cantilever of the microcantilever resonator through a piezoelectric resonator to detect the frequency response of the cantilever. Then, the frequency scan of the frequency response analysis module of the phase-locked amplifier is selected to scan the frequency range after the pump signal is applied in the first-order torsional mode: 230kHz-435kHz, 92.87kHz-94.87kHz, 235.6kHz-239.3kHz, 425kHz-428.7kHz. The sideband spectrum response curve of the cantilever is displayed on a computer connected to the phase-locked amplifier. The line widths of the red sideband and the blue sideband are obtained by line width fitting, which are , ;

[0020] S23: Finding the second-order bending mode eigenfrequency of a microcantilever beam through the sideband spectrum response curve f 2Frequency shift to f 2' and nonlinearly couples with the first-order torsion mode to produce red and blue sidebands. The frequency of the red sideband is f r , the blue sideband frequency is f b , line width , It is effectively reduced and a narrow line width sideband is obtained;

[0021] The implementation process of step S3 is:

[0022] S31: Select the phase-locked loop module of the phase-locked amplifier, input the corresponding frequency and phase of the second-order bending mode, the first-order torsional mode, the red sideband and the blue sideband, and realize the phase-locked frequency tracking of the second-order bending mode, the first-order torsional mode, the red sideband and the blue sideband;

[0023] S32: Then select the plotter that comes with the lock-in amplifier, and the time domain signals of the second-order bending mode, the first-order torsion mode, the red sideband and the blue sideband of the cantilever beam of the microcantilever beam resonator are displayed on the computer connected to the lock-in amplifier;

[0024] S33: By performing Allan deviation analysis on the time domain signals of the second-order bending mode, the first-order torsion mode, the red sideband and the blue sideband, the Allan deviation is obtained.

[0025] Preferably, the process of determining the eigenfrequency in step S1 is:

[0026] S11: The probe of the laser Doppler vibrometer emits a laser, which is aimed at the tip of the cantilever of the micro-cantilever resonator. The focusing effect can be observed through the optical CCD. The optical CCD is an image collector that can clearly see the beam and the point where the laser is focused. The focusing effect of the laser is observed through it, and the laser Doppler vibrometer is used to perform frequency scanning and vibration signal collection on the micro-cantilever resonator;

[0027] S12: The phase-locked amplifier inputs a detection voltage signal to the microcantilever resonator to stimulate vibration. V probe The detection voltage is 100mV V probe The micro-cantilever resonator's micro-cantilever displacement and velocity signals are collected by the probe of the Doppler vibrometer and converted into voltage signals by the controller. After noise reduction processing by the phase-locked amplifier, the frequency response curve of the micro-cantilever is displayed on the computer connected to the phase-locked amplifier. By observing the frequency response curve on the computer, the frequencies of the first two peaks on the curve are the second-order bending mode frequency and the first-order torsional mode frequency of the micro-cantilever. The second-order bending mode eigenfrequency is recorded. f 2nd and 1st torsional mode eigenfrequencies f t , and the line widths are , .

[0028] The lock-in amplifier can perform Fourier transform on the input signal, thereby eliminating noise signals other than specific frequency components in the detected signal, improving the signal-to-noise ratio, and displaying the signal on a computer.

[0029] Preferably, in step S11, the wavelength of the laser emitted by the probe of the laser Doppler vibrometer is 633nm. In step S11, the Doppler vibrometer detects the displacement and velocity of the moving object through the Doppler effect of the laser. The Doppler vibrometer is a non-contact optical sensor that can detect the displacement and velocity of the moving object through the Doppler effect of the laser. When the laser emitted from the vibrometer laser probe irradiates the moving object, the laser reflected or scattered back from the moving object will undergo an obvious frequency shift. By measuring the frequency shift of the reflected light and the phase relative to the incident light, the displacement and velocity of the moving object can be calculated. The 633nm laser emitted by the Doppler vibrometer probe is focused onto the surface of the micro-cantilever beam through the microscope objective lens, and the detected vibration signal is converted into a voltage signal by the Doppler vibrometer controller.

[0030] Preferably, in step S12, the second-order bending mode eigenfrequency f 2 is 85.54kHz, the first-order torsional mode eigenfrequency f t is 332.19kHz, and the line widths are =35Hz, =30Hz.

[0031] Preferably, f 2' is 93.87kHz, red sideband frequency f r 238.32kHz, line width 5Hz, blue sideband frequency f b 426.06kHz, line width is 20Hz; relative to the line width of the second-order bending mode, the red sideband line width 、Blue sideband width The red sideband width is reduced to 1 / 7 and 4 / 7 of the second-order bending mode line width respectively; relative to the first-order torsional mode line width, 、Blue sideband width They are reduced to 1 / 6 and 2 / 3 of the linewidth of the first-order torsional mode respectively.

[0032] Preferably, in step S21, the pump voltage V pump The increase method is 250mV, 275mV, 300mV, 325mV, and 350mV.

[0033] Preferably, in S22, the detection voltage signal is 5 mV.

[0034] Preferably, in step S33, the Allan deviation of the second-order bending mode is obtained as σ 2=5.9×10 -3, the Allan deviation of the first-order torsional mode is σ t =4.2×10 -3 , the Allan deviations of the red sideband and the blue sideband are σ r =7.3×10 -4 , σ b =1.3×10 -3 Compared with the second-order bending mode, the Allan deviation of the red sideband is reduced to 12.4% of the Allan deviation of the second-order bending mode, the Allan deviation of the blue sideband is reduced to 22% of the Allan deviation of the second-order bending mode, the Allan deviation of the red sideband is reduced to the Allan deviation of the first-order torsional mode, the Allan deviation of the red and blue sidebands is reduced to 17.4% of the Allan deviation of the first-order torsional mode, and the Allan deviation of the blue sideband is reduced to 30.9% of the Allan deviation of the first-order torsional mode, obtaining sidebands with high frequency stability.

[0035] For any details not provided in the present invention, please refer to the prior art.

[0036] The beneficial effects of the present invention are:

[0037] 1. The present invention only needs to use a signal generator to output a pump signal to modulate the microresonator, so as to obtain the sideband of the microresonator with narrow line width and high frequency stability, which has strong principle and is easy to operate.

[0038] 2. The device of the present invention is simple, and the micro-cantilever beam resonator used is small in size, high in sensitivity, and easy to integrate.

[0039] 3. The present invention obtains the sidebands of narrow linewidth and high frequency stability of the microcantilever resonator in a single cantilever system for the first time, which is of great significance for improving the frequency stability of the microcantilever resonator and studying the nonlinear dynamic behavior of the resonator.

[0040] 4. The present invention adopts a non-contact control method which is accurate and effective, will not damage the micro-resonator, and has no stray resonance. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The drawings in the specification, which constitute a part of the present application, are used to provide further understanding of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute improper limitations on the present application.

[0042] Figure 1 A schematic diagram of the structure of a device for obtaining high-frequency stability sidebands for a resonantly excited microresonator of the present invention;

[0043] Figure 2 It is a schematic diagram of the frequency response of the second-order bending mode of the cantilever beam under the detection voltage;

[0044] Figure 3 It is a schematic diagram of the frequency response of the first-order torsional mode of the cantilever beam under the detection voltage;

[0045] Figure 4 Schematic diagram of the principle of realizing nonlinear coupling of microcantilever beam parameter excitation;

[0046] Figure 5 are the red and blue sidebands obtained when pumping in the first-order torsional mode;

[0047] Figure 6 Schematic diagram of the change of red sideband with voltage during first-order torsional mode pumping;

[0048] Figure 7 Schematic diagram of the change of blue sideband with voltage during first-order torsional mode pumping;

[0049] Figure 8 is the Allan deviation diagram of the second-order bending mode;

[0050] Fig. 9 is the Allan deviation diagram of the first-order torsional mode;

[0051] Fig.10 It is the Allan deviation diagram of the red sideband;

[0052] Fig.11 Allan deviation diagram for the blue sideband;

[0053] In the figure, 1-micro cantilever beam resonator, 2-piezoelectric resonator, 3-vacuum cavity, 4-phase-locked amplifier, 5-probe, 6-controller, 7-signal generator, 8-laser, and 9-computer. DETAILED DESCRIPTION

[0054] In order to enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of the present invention are clearly and completely described below in conjunction with the drawings in the implementation of this specification, but are not limited to this. Anything not fully described in the present invention shall be based on the conventional technology in the art.

[0055] Example 1

[0056] A method for obtaining high-frequency stability sidebands by resonantly exciting a microresonator comprises the following steps:

[0057] S1: Measure the frequency response of the second-order bending mode and the first-order torsion mode of the microcantilever beam resonator under the detection voltage to determine the eigenfrequency;

[0058] S2: Pumping at the first-order torsional mode induces nonlinear mode coupling between the second-order bending mode and the first-order torsional mode, and obtains a narrow linewidth sideband;

[0059] S3: The frequency stability of the microcantilever beam resonator 1 is measured using a phase-locked loop (PLL) amplifier 4, and the sideband with high frequency stability is obtained;

[0060] The implementation process of step S2 is:

[0061] S21: The signal generator 7 outputs a frequency of f p The pump signal is related to the eigenfrequency of the first-order torsional mode. f t Same, 332.19 kHz, and gradually increase the pump voltage V pump , V pump The magnitude of the pump signal increases gradually from 250mV to 350mV, and the increase is 250mV, 275mV, 300mV, 325mV, and 350mV. The pump signal is applied to the cantilever beam of the microcantilever beam resonator 1 through the piezoelectric resonator 2.

[0062] S22: A detection voltage signal of 5 mV is outputted by the phase-locked amplifier 4, and the detection voltage is applied to the cantilever of the micro-cantilever resonator 1 through the piezoelectric resonator to detect the frequency response of the cantilever. Then, the frequency scan of the frequency response analysis module provided by the phase-locked amplifier 4 is selected to scan the frequency range after the pump signal is applied in the first-order torsional mode: 230 kHz-435 kHz, 92.87 kHz -94.87 kHz, 235.6 kHz-239.3 kHz, 425 kHz-428.7 kHz. The sideband spectrum response curve of the cantilever is displayed on the computer 9 connected to the phase-locked amplifier 4. The line widths of the red sideband and the blue sideband are obtained by line width fitting, which are respectively , ;

[0063] The frequency response analysis module is a frequency response analyzer module in the lock-in amplifier. It is an existing module that can analyze the frequency response. Figure 5 It is shown that red and blue sidebands are obtained when pumping in the first-order torsional mode. Figure 6 The diagram shows the change of the red sideband with voltage when pumping in the first-order torsional mode, with a line width of 5Hz. Figure 7 The figure shows the change of blue sideband with voltage in the first-order torsional mode pump, with a line width of 20Hz.

[0064] S23: Finding the second-order bending mode eigenfrequency of a microcantilever beam through the sideband spectrum response curve f2Frequency shift to f 2' and nonlinearly couples with the first-order torsion mode to produce red and blue sidebands. The frequency of the red sideband is f r , the blue sideband frequency is f b , line width , It is effectively reduced and a sideband with narrow line width is obtained.

[0065] In this embodiment, f 2' is 93.87kHz, red sideband frequency f r 238.32kHz, line width 5Hz, blue sideband frequency f b 426.06kHz, line width is 20Hz; relative to the line width of the second-order bending mode, the red sideband line width 、Blue sideband width The red sideband width is reduced to 1 / 7 and 4 / 7 of the second-order bending mode line width respectively; relative to the first-order torsional mode line width, 、Blue sideband width They are reduced to 1 / 6 and 2 / 3 of the linewidth of the first-order torsional mode respectively.

[0066] In S23 of the present invention, narrow line width red and blue sidebands are obtained. This is because the parameter excitation generates a nonlinear channel, such as Figure 4 As shown in Figure 1, the channel is formed by the interaction of the bending mode and the torsion mode for energy transfer between the coupled modes. From the perspective of quantum physics, this process involves a probe phonon from the second bending mode. and from the torsion mode The pump phonon combines and forms two phonons at the red and blue sidebands, described by the phonon interaction: As a result, the vibration of the torsional mode is damped, while the vibration of the sum and difference frequencies are excited and enhanced, generating red and blue sidebands due to the increased phonon response. The narrow linewidth can be attributed to the fact that the phonon injection provides a stable energy source that can maintain the energy of the sidebands, thereby reducing the impact of environmental fluctuations and thermal noise on the resonator frequency, thus enabling high frequency stability.

[0067] The implementation process of step S3 is:

[0068] S31: Select the phase-locked loop module of the phase-locked amplifier 4, input the corresponding frequencies and phases of the second-order bending mode, the first-order torsional mode, the red sideband and the blue sideband, and realize the phase-locked frequency tracking of the second-order bending mode, the first-order torsional mode, the red sideband and the blue sideband;

[0069] The second-order bending mode and the first-order torsional mode before the pump signal is applied are input, and the frequency and measurement bandwidth corresponding to the red sideband and the blue sideband generated after the pump are generally higher than the natural line width twice the frequency to ensure stable phase-locked frequency tracking of the second-order bending mode, the first-order torsional mode, the red sideband and the blue sideband. In this embodiment, the eigenfrequency of the second-order bending mode is f 2 = 85.54kHz, the measurement bandwidth is 70Hz, and the eigenfrequency of the first-order torsional mode is f t =332.19kHz, the measurement bandwidth is 60Hz, the red sideband frequency is 238.32kHz, the measurement bandwidth is 10Hz, the blue sideband frequency is 426.06kHz, and the measurement bandwidth is 40Hz.

[0070] A closed-loop phase-locked loop (PLL) module is used to accurately evaluate the Allan deviation. This is achieved by using the built-in function of the phase-locked amplifier, by inputting the frequencies and measurement bandwidths of the second-order bending mode, the first-order torsional mode, the red sideband, and the blue sideband as described in S31, to ensure that the PLL can track the frequency fluctuations within its bandwidth within a specific time scale. It should be noted that when setting the measurement bandwidth of the phase-locked loop, if the bandwidth is too high, it may cause poor noise performance due to higher frequency fluctuations; if the bandwidth is too low, the phase-locked loop will not be able to effectively track frequency fluctuations.

[0071] S32: Then the plotter (Plotter) provided by the phase-locked amplifier 4 is selected, and the time domain signals of the second-order bending mode, the first-order torsion mode, the red sideband and the blue sideband of the cantilever beam of the micro-cantilever beam resonator 1 are displayed on the computer connected to the phase-locked amplifier;

[0072] The time domain signal in step S32 is usually characterized by Allan deviation, which represents the functional relationship between the average frequency fluctuation fraction within a time interval τ and the average time τ:

[0073] ;

[0074] in, M is the total number of samples of the resonant frequency, is the average value of each integration time, τ represents the sampling time, is the center frequency.

[0075] Allan deviation is a method of measuring the variance of an estimator over different integration times. It provides insight into the various noise sources that affect the measurement. Unlike conventional standard deviation measurements, Allan deviation analysis can identify different noise sources. Gaussian noise and random noise are typical noise sources that affect measurements. Fast fluctuations create random noise, while slow drifts occur over longer time scales, resulting in increased deviations for higher integration times. The Allan deviation plot directly shows the magnitude of the noise as a function of integration time on a logarithmic scale, making it easy to identify the various noise and drifts in different regimes.

[0076] S33: By performing Allan deviation analysis on the time domain signals of the second-order bending mode, the first-order torsion mode, the red sideband and the blue sideband, the Allan deviation is obtained.

[0077] In step S33, Figures 8 to 11 As shown, the Allan deviation of the second-order bending mode is obtained as σ 2=5.9×10 -3 , the Allan deviation of the first-order torsional mode is σ t =4.2×10 -3 , the Allan deviations of the red sideband and the blue sideband are σ r =7.3×10 -4 , σ b =1.3×10 -3 Compared with the second-order bending mode, the Allan deviation of the red sideband is reduced to 12.4% of the Allan deviation of the second-order bending mode, the Allan deviation of the blue sideband is reduced to 22% of the Allan deviation of the second-order bending mode, the Allan deviation of the red sideband is reduced to the Allan deviation of the first-order torsional mode, the Allan deviation of the red and blue sidebands is reduced to 17.4% of the Allan deviation of the first-order torsional mode, and the Allan deviation of the blue sideband is reduced to 30.9% of the Allan deviation of the first-order torsional mode, obtaining sidebands with high frequency stability.

[0078] Example 2

[0079] A method for obtaining a high-frequency stability sideband by resonantly excited microresonator is as described in Example 1, except that the process of determining the eigenfrequency in step S1 is:

[0080] S11: The probe 5 of the laser Doppler vibrometer emits a 633nm laser, and the laser 8 is aimed at the tip of the cantilever beam of the micro-cantilever beam resonator 1. The focusing effect can be observed through the optical CCD. The optical CCD is an image collector, which can clearly see the beam and the point where the laser is focused. The focusing effect of the laser is observed through it, and the laser Doppler vibrometer is used to perform frequency scanning and vibration signal collection on the micro-cantilever beam resonator 1;

[0081] The Doppler vibrometer detects the displacement and velocity of a moving object through the Doppler effect of laser. The Doppler vibrometer is a non-contact optical sensor that can detect the displacement and velocity of a moving object through the Doppler effect of laser. When the laser emitted from the vibrometer laser probe is irradiated onto a moving object, the laser reflected or scattered back from the moving object will undergo a significant frequency shift. By measuring the frequency shift of the reflected light and the phase relative to the incident light, the displacement and velocity of the moving object can be calculated. The 633nm laser emitted by the Doppler vibrometer probe is focused onto the surface of the micro-cantilever beam through the microscope objective lens, and the detected vibration signal is converted into a voltage signal by the Doppler vibrometer controller.

[0082] S12: The phase-locked amplifier 4 inputs a detection voltage signal to the microcantilever beam resonator 1 to excite vibration. V probe The detection voltage is 100mV V probe The micro-cantilever resonator 1 is emitted by the phase-locked amplifier and can be displayed and controlled by the computer connected thereto, and the required values ​​can be directly input on the computer). The displacement and velocity signals of the micro-cantilever resonator 1 are collected by the probe 5 of the Doppler vibrometer and converted into voltage signals by the controller. After being subjected to noise reduction processing by the phase-locked amplifier 4, the frequency response curve of the micro-cantilever is displayed on the computer connected to the phase-locked amplifier. By observing the frequency response curve on the computer, the frequencies of the first two peaks appearing on the curve are the second-order bending mode frequency and the first-order torsional mode frequency of the micro-cantilever. The second-order bending mode eigenfrequency is recorded. f 2nd and 1st torsional mode eigenfrequencies f t , and the line widths are , ;

[0083] like Figure 2 It is a schematic diagram of the frequency response of the second-order bending mode of the cantilever beam under the detection voltage. Figure 3 This is a schematic diagram of the frequency response of the first-order torsion mode of the cantilever beam under the detection voltage. By observing the frequency response curve on the computer, the eigenfrequency of the second-order bending mode is f 2 is 85.54kHz, the first-order torsional mode eigenfrequency f tis 332.19kHz, and the line widths are =35Hz, =30Hz.

[0084] The lock-in amplifier can perform Fourier transform on the input signal, thereby eliminating noise signals other than specific frequency components in the detected signal, improving the signal-to-noise ratio, and displaying the signal on a computer.

[0085] Example 3

[0086] A device for resonantly exciting a microresonator to obtain high frequency stability sidebands, such as Figure 1 As shown, the method for realizing the resonant excitation micro-resonator of Example 2 to obtain high-frequency stability sidebands includes a laser Doppler vibrometer, a signal generator 7, a piezoelectric resonator 2, a micro-cantilever resonator 1, a phase-locked amplifier 4 and a computer 9, the laser Doppler vibrometer includes a probe 5 and a controller 6, the probe 5 is used to emit a laser to align the cantilever tip of the micro-cantilever resonator, and the controller 6 is used to convert the displacement and velocity signals detected by the probe into voltage signals;

[0087] The laser Doppler vibrometer, the phase-locked amplifier 4, the signal generator 7, and the piezoelectric resonator 2 are connected in sequence; the phase-locked amplifier 4 is connected to the computer 9, the signal generator 7 is connected to the piezoelectric resonator 2, and the microcantilever beam resonator 1 and the piezoelectric resonator 2 are placed in the vacuum chamber 3;

[0088] The piezoelectric resonator 2 is used to excite the micro-cantilever resonator 1; the signal generator 7 is used to apply a pump signal to the cantilever; the laser Doppler vibrometer is used to collect the vibration signal of the micro-cantilever resonator 1 and transmit it to the phase-locked amplifier 4, and the phase-locked amplifier 4 is used to perform mathematical processing on the received signal and display the result on the computer 9.

[0089] A displacement stage is provided at the bottom of the vacuum chamber 3. The displacement stage has screws for adjusting up, down, left, and right. The screws can be adjusted manually to adjust the position of the vacuum chamber and thus the position of the microcantilever beam resonator. The vacuum degree of the vacuum chamber is 10 -2 mbar;

[0090] The microcantilever beam resonator 1 is a rectangular microcantilever beam fixed at one end, including a support base and a cantilever, both of which are made of single crystal silicon; the cantilever is a free end, and the support base is fixed on the piezoelectric resonator with glue; the size of the cantilever is: 450μm long, 50μm wide, and 2μm thick; the piezoelectric resonator is a circular ceramic piece, the material is lead zirconate titanate (PZT), and its piezoelectric coefficient d 33 350 pmV -1 ,The dimensions of the piezoelectric resonator are: 30mm in diameter and 2mm in thickness.

[0091] The signal generator 7 is used to apply an external excitation pump signal to the resonator;

[0092] The laser Doppler vibrometer is a non-contact optical sensor used to detect the displacement and velocity changes of the microcantilever beam. The model is OFV-5000 / 534, and the focus spot is 10 μm.

[0093] The phase-locked amplifier 4 is a 7265 digital phase-locked amplifier produced by Signal Recovery Company, with a frequency range of 0.001Hz-250kHz and a voltage sensitivity of 2nV-1V. It is used to output detection signals, collect and reduce noise of the vibration signals of the cantilever beam, and display the results on the computer 9.

[0094] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for obtaining high frequency stability sidebands by resonantly exciting a microresonator, characterized in that: The steps include: S1: Measure the frequency response of the second-order bending mode and the first-order torsion mode of the microcantilever beam resonator under the detection voltage to determine the eigenfrequency; S2: Pumping at the first torsion mode induces nonlinear mode coupling between the second bending mode and the first torsion mode, resulting in a narrow linewidth sideband; S3: The frequency stability of the microcantilever resonator was measured using a lock-in amplifier, and the sideband with high frequency stability was obtained; The implementation process of step S2 is: S21: The signal generator output frequency is f p The pump signal, the magnitude of which is related to the eigenfrequency of the first-order torsional mode f t Same, and gradually increase the pump voltage V pump , V pump The size of is gradually increased from 250mV to 350mV, and this pump signal is applied to the cantilever beam of the microcantilever beam resonator through the piezoelectric resonator; S22: A detection voltage signal is output by a phase-locked amplifier and applied to the cantilever of the microcantilever resonator through a piezoelectric resonator to detect the frequency response of the cantilever. Then, the frequency scan of the frequency response analysis module of the phase-locked amplifier is selected to scan the frequency range after the pump signal is applied in the first-order torsional mode: 230kHz-435kHz, 92.87kHz -94.87 kHz, 235.6 kHz-239.3 kHz, 425kHz-428.7kHz. The sideband spectrum response curve of the cantilever is displayed on a computer connected to the phase-locked amplifier. The line widths of the red sideband and the blue sideband are obtained by line width fitting, which are 230kHz-435kHz, 92.87kHz -94.87 kHz, 235.6 kHz-239.3 kHz, and 425kHz-428.7kHz, respectively. , ; S23: Finding the second-order bending mode eigenfrequency of a microcantilever beam through the sideband spectrum response curve f 2Frequency shift to f 2' and nonlinearly couples with the first-order torsion mode to produce red and blue sidebands. The frequency of the red sideband is f r , the blue sideband frequency is f b , line width , It is reduced and a sideband with narrow line width is obtained; The implementation process of step S3 is: S31: Select the phase-locked loop module of the phase-locked amplifier, input the corresponding frequency and phase of the second-order bending mode, the first-order torsional mode, the red sideband and the blue sideband, and realize the phase-locked frequency tracking of the second-order bending mode, the first-order torsional mode, the red sideband and the blue sideband; S32: Then the plotter provided by the phase-locked amplifier is selected, and the time domain signals of the second-order bending mode, the first-order torsion mode, the red sideband and the blue sideband of the cantilever beam of the microcantilever beam resonator are displayed on the computer connected to the phase-locked amplifier; S33: By performing Allan deviation analysis on the time domain signals of the second-order bending mode, the first-order torsion mode, the red sideband and the blue sideband, the Allan deviation is obtained.

2. The method for obtaining high frequency stability sidebands of a resonantly excited microresonator according to claim 1, characterized in that: The process of determining the eigenfrequency in step S1 is: S11: The probe of the laser Doppler vibrometer emits a laser, the laser is aimed at the tip of the cantilever of the micro-cantilever resonator, and the laser Doppler vibrometer is used to perform frequency scanning and vibration signal collection on the micro-cantilever resonator; S12: The phase-locked amplifier inputs a detection voltage signal to the microcantilever resonator to stimulate vibration. V probe The size is 100mV. The displacement and velocity signals of the microcantilever resonator are collected by the probe of the Doppler vibrometer and converted into voltage signals by the controller. After noise reduction processing by the phase-locked amplifier, the frequency response curve of the microcantilever is displayed on the computer connected to the phase-locked amplifier. By observing the frequency response curve on the computer, the frequencies of the first two peaks appearing on the curve are the second-order bending mode frequency and the first-order torsional mode frequency of the microcantilever. The second-order bending mode eigenfrequency is recorded. f 2nd and 1st torsional mode eigenfrequencies f t , and the line widths are , .

3. The method for obtaining high frequency stability sidebands of a resonantly excited microresonator according to claim 2, characterized in that: In step S11 , the wavelength of the laser emitted by the probe of the laser Doppler vibrometer is 633 nm.

4. The method for obtaining high frequency stability sidebands of a resonantly excited microresonator according to claim 3, characterized in that: In step S21, the pump voltage V pump The increase method is 250mV, 275mV, 300mV, 325mV, and 350mV.

5. The method for obtaining high frequency stability sidebands of a resonantly excited microresonator according to claim 4, characterized in that: In S22, the detection voltage signal is 5 mV.

6. The method for obtaining high frequency stability sidebands of a resonantly excited microresonator according to claim 5, characterized in that: In step S33, the Allan deviation of the second-order bending mode is obtained as σ 2=5.9×10 -3 , the Allan deviation of the first-order torsional mode is σ t =4.2×10 -3 , the Allan deviations of the red sideband and the blue sideband are σ r =7.3×10 -4 , σ b =1.3×10 -3 Compared with the second-order bending mode, the Allan deviation of the red sideband is reduced to 12.4% of the Allan deviation of the second-order bending mode, the Allan deviation of the blue sideband is reduced to 22% of the Allan deviation of the second-order bending mode, the Allan deviation of the red sideband is reduced to the Allan deviation of the first-order torsional mode, the Allan deviation of the red and blue sidebands is reduced to 17.4% of the Allan deviation of the first-order torsional mode, and the Allan deviation of the blue sideband is reduced to 30.9% of the Allan deviation of the first-order torsional mode, obtaining sidebands with high frequency stability.

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