In this paper,a novel four-prong quartz tuning fork(QTF)was designed with enlarged deformation area,large prong gap,and low resonant frequency to improve its performance in laser spectroscopy sensing.A theoretical sim...In this paper,a novel four-prong quartz tuning fork(QTF)was designed with enlarged deformation area,large prong gap,and low resonant frequency to improve its performance in laser spectroscopy sensing.A theoretical simulation model was established to optimize the design of the QTF structure.In the simulation of quartz-enhanced photoacoustic spectroscopy(QEPAS)technology,the maximum stress and the surface charge density of the four-prong QTF demonstrated increases of 11.1-fold and 15.9-fold,respectively,compared to that of the standard two-prong QTF.In the simulation of light-induced thermoelastic spectroscopy(LITES)technology,the surface temperature difference of the four-prong QTF was found to be 11.4 times greater than that of the standard QTF.Experimental results indicated that the C_(2)H_(2)-QEPAS system based on this innovative design improved the signal-to-noise-ratio(SNR)by 4.67 times compared with the standard QTF-based system,and the SNR could increase up to 147.72 times when the four-prong QTF was equipped with its optimal acoustic micro-resonator(AmR).When the average time of the system reached 370 s,the system achieved a MDL as low as 21 ppb.The four-prong QTF-based C_(2)H_(2)-LITES system exhibited a SNR improvement by a factor of 4.52,and a MDL of 96 ppb was obtained when the average time of the system reached 100 s.The theoretical and experimental results effectively demonstrated the superiority of the four-prong QTF in the field of laser spectroscopy sensing.展开更多
Grooved tuning forks with hierarchical structures have become some of the most widely used piezoelectric quartz microelectromechanical system devices;however,fabricating these devices requires multi-step processes due...Grooved tuning forks with hierarchical structures have become some of the most widely used piezoelectric quartz microelectromechanical system devices;however,fabricating these devices requires multi-step processes due to the complexity of etching of quartz,particularly in specific orientations of the crystal lattice.This paper proposes a one-step fabrication strategy that can form a complete hierarchical structure with only a single etching process using novel lithography patterns.The core principle of this strategy is based on the effect of the size of the groove patterns on quartz etching,whereby trenches of varying depths can be created in a fixed etching time by adjusting the width of the hard mask.Specifically,the device outline and grooved structure can be completed using a seamlessly designed etching pattern and optimized time.Furthermore,the etching structure itself influences the etching results.It was found that dividing a wide trench by including a wall to separate it into two narrow trenches significantly reduces the etching rate,allowing for predictable tuning of the etching rate for wider grooves.This effectively increases the usability and flexibility of the one-step strategy.This was applied to the manufacture of an ultra-small quartz grooved tuning fork resonator with a frequency of 32.768 kHz in a single step,increasing production efficiency by almost 45%and reducing costs by almost 30%compared to current methods.This has great potential for improving the productivity of grooved tuning fork devices.It can also be extended to the fabrication of other quartz crystal devices requiring hierarchical structures.展开更多
In this paper,a novel self-designed inverted-triangular lithium niobate tuning fork(LiNTF)was used to construct gas sensing system for the first time.The optimal ratio of the upper and lower boundaries of the inverted...In this paper,a novel self-designed inverted-triangular lithium niobate tuning fork(LiNTF)was used to construct gas sensing system for the first time.The optimal ratio of the upper and lower boundaries of the inverted-triangular LiNTF is found by scanning through finite element analysis(FEA).The surface charge density and stress value of the inverted-triangular LiNTF are both higher than those of the standard quartz tuning fork(QTF).In the lithium niobate-enhanced photoacoustic spectroscopy(LiNPAS)sensing system,the 2f peak and signal-to-noise ratio(SNR)of the inverted-triangular LiNTF are 7.41 times and 5.89 times those of the standard QTF,respectively.After forming acoustic standing wave field with the acoustic micro-resonator(AmR),the LiNPAS system achieves an SNR 56.16 times higher than without the AmR.Based on Allan variance analysis,the system achieves a minimum detection limit(MDL)of 7.25 ppb with an averaging time of 800 seconds.In the light-induced thermoelastic spectroscopy(LITES)sensing system,the 2f peak and SNR of the inverted-triangular LiNTF are 7.82 times and 6.03 times those of the standard QTF,respectively.When the averaging time reaches 100 s,the MDL of the system is found to be 25.78 ppb.展开更多
The micro quartz crystal tuning fork gyroscope is a new type of vibratory gyroscope. The gyroscope should be analyzed and simulated early in the design stage in order to offer reliable basis for design and to shorten ...The micro quartz crystal tuning fork gyroscope is a new type of vibratory gyroscope. The gyroscope should be analyzed and simulated early in the design stage in order to offer reliable basis for design and to shorten the period of development. Thus the vibratory characteristics of the gyroscope is simulated with the finite element method of coupled field. The optimum exciting frequency and the factors which influence the gyroscope sensitivity are determined. The method for adjusting the frequency deviation between driving and detecting modes is also proposed.展开更多
We present the fabrication and testing of a silicon carbide （SiC） balanced mass doublended tuning fork that survives harsh environments without compromising the device strain sensitivity and resolution bandwidth. Th...We present the fabrication and testing of a silicon carbide （SiC） balanced mass doublended tuning fork that survives harsh environments without compromising the device strain sensitivity and resolution bandwidth. The device features a material stack that survives corrosive environments and enables high-temperature operation. To perform hightemperature testing, a specialized setup was constructed that allows the tuning fork to be characterized using traditional silicon electronics. The tuning fork has been operated at 600°C in the presence of dry steam for short durations. This tuning fork has also been tested to 64 000 G using a hard-launch, soft-catch shock implemented with a light gas gun. However, the device still has a strain sensitivity of 66 Hz/μe and strain resolution of 0. 045 μe in a 10 kHz bandwidth. As such, this balanced-mass double-ended tuning fork can be used to create a variety of different sensors including strain gauges, accelerometers, gyroscopes, and pressure transducers. Given the adaptable fabrication process flow, this device could be useful to micro-electro-mechanical systems （MEMS） designers creating sensors for a variety of different applications.展开更多
To enhance the coherence and reliability of the double-ended tuning fork(DETF)resonator,a measurement system of resonator vibration is presented to check its dynamic characteristics.Laser Doppler techniques are utiliz...To enhance the coherence and reliability of the double-ended tuning fork(DETF)resonator,a measurement system of resonator vibration is presented to check its dynamic characteristics.Laser Doppler techniques are utilized and the relation between DETF vibration velocity and output current of photodetector is obtained.Resonator vibration equation is also analyzed and its driving power only depends on the direct current bias voltage and the amplitude of alternative voltage.Furthermore,a special resonator driving control circuit based on measurement is designed.The amplitude and frequency of circuit is controlled by a computer so that highly stable and strong driving signal can be output.Experiments on driving and measuring double-ended tuning fork have been done,The frequency of driving signal is 8 kHz and the peak-to-peak value of driving voltage is 140 V.Experimental results indicate resonator can be drived stably by driving control circuit and dynamic characteristics of DETF may be measured in real time.展开更多
This paper is focused on electrode design for piezoelectric tuning fork resonators.The relationship between the performance and electrode pattern of aluminum nitride piezoelectric tuning fork resonators vibrating in t...This paper is focused on electrode design for piezoelectric tuning fork resonators.The relationship between the performance and electrode pattern of aluminum nitride piezoelectric tuning fork resonators vibrating in the in-plane flexural mode is investigated based on a set of resonators with different electrode lengths,widths,and ratios.Experimental and simulation results show that the electrode design impacts greatly the multimode effect induced from torsional modes but has little influence on other loss mechanisms.Optimizing the electrode design suppresses the torsional mode successfully,thereby increasing the ratio of impedance at parallel and series resonant frequencies(R_(p)/R_(s))by more than 80%and achieving a quality factor(Q)of 7753,an effective electromechanical coupling coefficient(kt_(eff)^(2))of 0.066%,and an impedance at series resonant frequency(R_(m))of 23.6 kΩ.The proposed approach shows great potential for high-performance piezoelectric resonators,which are likely to be fundamental building blocks for sensors with high sensitivity and low noise and power consumption.展开更多
This paper proposes an improved design of micromachined tuning fork gyroscope （M-TFG） to decouple the cross talk between driving and sensing directions better and to increase resolution. By employing dual-folds spri...This paper proposes an improved design of micromachined tuning fork gyroscope （M-TFG） to decouple the cross talk between driving and sensing directions better and to increase resolution. By employing dual-folds spring suspension, the drive mode and the sense mode are mechanically decoupled. Through careful layout design of the location of the dual-folds spring suspension and the drive combs, the mechanical coupling effect is further decreased by isolating the unwanted excitation from detection. The quality factor investigation demonstrates that high quality factor can be attained by using this structure, which can bring in accurate resolution. As a result, this design has the potential to accomplish low bias drift and accurate resolution for initial level applications.展开更多
We have built an atomic force microscope using a quartz tuning fork as sensor. The excitation method we adopted, the electrical excitation, introduces stray capacitance into the signal-processing circuit. In this repo...We have built an atomic force microscope using a quartz tuning fork as sensor. The excitation method we adopted, the electrical excitation, introduces stray capacitance into the signal-processing circuit. In this report, we demonstrated a simple but effective method to compensate for this parasitic capacitance by adding a compensator circuit consisting of an inverting amplifier and a capacitor. The capacitor is connected in series with the inverting amplifier and the compensator is connected in parallel with the quartz tuning fork. The resonance curve of the system measured after adding the homemade compensator resembles that of a pure RLC circuit, meaning that the stray capacitance is successfully eliminated. Furthermore, we tried to use our equipment to measure PDMS sample and got clean data. This system can be further combined with confocal microscope and diamond with NV defect to build scanning NV magnetometry.展开更多
A highly sensitive light-induced thermoelectric spectroscopy(LITES)sensor based on a multi-pass cell(MPC)with dense spot pattern and a novel quartz tuning fork(QTF)with low resonance frequency is reported in this manu...A highly sensitive light-induced thermoelectric spectroscopy(LITES)sensor based on a multi-pass cell(MPC)with dense spot pattern and a novel quartz tuning fork(QTF)with low resonance frequency is reported in this manuscript.An erbi-um-doped fiber amplifier(EDFA)was employed to amplify the output optical power so that the signal level was further enhanced.The optical path length(OPL)and the ratio of optical path length to volume(RLV)of the MPC is 37.7 m and 13.8 cm^(-2),respectively.A commercial QTF and a self-designed trapezoidal-tip QTF with low frequency of 9461.83 Hz were used as the detectors of the sensor,respectively.The target gas selected to test the performance of the system was acetylene(C2H2).When the optical power was constant at 1000 mW,the minimum detection limit(MDL)of the C2H2-LITES sensor can be achieved 48.3 ppb when using the commercial QTF and 24.6 ppb when using the trapezoid-al-tip QTF.An improvement of the detection performance by a factor of 1.96 was achieved after replacing the commer-cial QTF with the trapezoidal-tip QTF.展开更多
This paper presents the design,fabrication,and characterization of a quartz tuning fork temperature sensor based on a new ZY-cut quartz crystal bulk acoustic wave resonator vibrating in a flexural mode.Design and perf...This paper presents the design,fabrication,and characterization of a quartz tuning fork temperature sensor based on a new ZY-cut quartz crystal bulk acoustic wave resonator vibrating in a flexural mode.Design and performance analysis of the quartz tuning fork temperature sensor were conducted and the thermal sensing characteristics were examined by measuring the resonance frequency shift of this sensor caused by an external temperature.Finite element method is used to analyze the vibratory modes and optimize the structure of the sensor.The sensor prototype was successfully fabricated and calibrated in operation from 0 to 100 ℃ with the thermo-sensitivity of 70×10-6/℃.Experimental results show that the sensor has high thermo-sensitivity,good stability,and good reproducibility.This work presents a high-precision low-power temperature sensor using the comprehensive thermal characterization of the ZY-cut quartz tuning fork resonator.展开更多
A highly sensitive carbon dioxide(CO_(2))sensor based on light-induced thermoelastic spectroscopy(LITES)utilizing a selfdesigned low-frequency quartz tuning fork(QTF)and a fiber-coupled multipass cell(MPC)is reported ...A highly sensitive carbon dioxide(CO_(2))sensor based on light-induced thermoelastic spectroscopy(LITES)utilizing a selfdesigned low-frequency quartz tuning fork(QTF)and a fiber-coupled multipass cell(MPC)is reported in this paper.The QTF with a low resonant frequency of 8675 Hz and a high Q factor of 11,675.64 was used to improve its energy accumulation time and the sensor’s signal level.The MPC with the fiber-coupled structure and optical length of 40 m was adopted to significantly increase the gas absorbance and reduce the optical alignment difficulty as well as improve the robustness of the sensor system.A distributed feedback(DFB),near-infrared diode laser with an emission wavelength of 1.57μm was used as an excitation source.The experimental results showed that this CO_(2)-LITES sensor had an excellent linear response to CO_(2) concentrations.The minimum detection limitation(MDL)of this CO_(2)-LITES sensor was obtained to be 445.91 ppm,and it could be improved to 47.70 ppm(parts per million)when the integration time of the system reached 500 s.Further improvement methods for the detection performance of such sensors were also discussed.展开更多
In this Letter,a quartz-enhanced photoacoustic spectroscopy(QEPAS)gas sensor based on a single off-beam acoustic micro-resonator(AmR)and dual quartz tuning forks(QTFs)was demonstrated for the first time,to our knowled...In this Letter,a quartz-enhanced photoacoustic spectroscopy(QEPAS)gas sensor based on a single off-beam acoustic micro-resonator(AmR)and dual quartz tuning forks(QTFs)was demonstrated for the first time,to our knowledge.The sensor offers advantages of a compact sensing structure and high acoustic energy utilization efficiency.The key parameters of the designed off-beam AmR were optimized based on standing wave enhancement characteristics.Water vapor(H2O)in the environment was chosen as the target gas to investigate the sensor performance.Under identical experimental conditions,the reported sensor achieved 15.02 times improvement in detection sensitivity compared to the bare QTF-based sensor system,as well as a 1.53 times enhancement over the traditional off-beam QEPAS technique.展开更多
A fully automated atomic force microscope(AFM)is presented.The mechanical motion of the AFM stage was controlled by three steppers.The fine motion of the AFM was controlled by an MCL one-axis piezo plate.A32.768kHz cr...A fully automated atomic force microscope(AFM)is presented.The mechanical motion of the AFM stage was controlled by three steppers.The fine motion of the AFM was controlled by an MCL one-axis piezo plate.A32.768kHz crystal tuning fork(TF)was used as the transducer with a probe attached.An acoustic sensor was used to measure the interactions between the probe and the sample.An SR850lock-in amplifier was used to monitor the TF signals.An additional lock-in amplifier was used to monitor the acoustic signal.A field programmable gate array(FPGA)board was used to collect the data in automatic mode.The main controller was coded with LabVIEW,which was in charge of Z-axis scan,signal processing and data visualization.A manual mode and an automatic mode were implemented in the controller.Users can switch the two modes at any time during the operation.This AFM system showed several advantages during the test operations.It is simple,flexible and easy to use.展开更多
In this paper,a novel highly sensitive methane(CH_(4))and acetylene(C_(2)H_(2))dual-gas light-induced thermoelectric spectroscopy(LITES)sensor based on Lissajous space-division multiplexed(LSDM)technology and trapezoi...In this paper,a novel highly sensitive methane(CH_(4))and acetylene(C_(2)H_(2))dual-gas light-induced thermoelectric spectroscopy(LITES)sensor based on Lissajous space-division multiplexed(LSDM)technology and trapezoidal-head quartz tuning fork(QTF)detector was reported for the first time.A theoretical LSDM model was established on the basis of three-mirror astigmatic multi-pass cell(MPC)and it was used to design a pair of Lissajous spot patterns with optical path length to volume ratios(OPL/Vs)of 13.5 cm^(-2) and 13.3 cm^(-2),respectively.Two self-designed trapezoidal-head QTFs with low resonant frequencies of less than 10 kHz and quality factor of~12000 were adopted to enhance the detection ability.Two kinds of fiber amplifier,erbium doped fiber amplifier(EDFA)and Raman fiber amplifier(RFA),were combined to amplify the output power of two diode lasers to improve the excitation strength.After optimization,minimum detection limit(MDL)of 268.8 ppb and 91.4 ppb for real-simultaneous CH_(4) and C_(2)H_(2) sensing were obtained,respectively.When the integration time of the system were 150 s and 100 s,the MDLs could be improved to 54.8 ppb and 26.1 ppb,accordingly.Further improvement methods for such sensor were discussed.展开更多
Gas sensing technology is widely applied in various fields,including environmental monitoring,industrial process control,medical diagnostics,safety warnings,and more.As a detection element,the quartz tuning fork(QTF)o...Gas sensing technology is widely applied in various fields,including environmental monitoring,industrial process control,medical diagnostics,safety warnings,and more.As a detection element,the quartz tuning fork(QTF)offers advantages such as high-quality factor(Q-factor),strong noise immunity,compact size,and low cost.Notably,its resonant characteristics significantly enhance system signal strength.Two spectroscopic techniques based on QTF detection,Quartz-enhanced photoacoustic spectroscopy(QEPAS)and light-induced thermoelastic spectroscopy(LITES),are currently research hotspots in the field of spectral sensing.This paper provides a comprehensive and detailed review and highlights pivotal innovations in these two QTF-based spectroscopic techniques.For QEPAS,these encompass high-power excitation methods,novel excitation sources,advanced QTF detection elements,and acoustic wave amplification strategies.Regarding LITES,the researches on optical cavity-enhanced approaches,modified QTF improvement mechanisms,integration with heterodyne demodulation technique,and combination with QEPAS were analyzed.These advances have enabled quartz-enhanced laser spectroscopy to achieve detection limits ranging from parts-per-billion(ppb)to parts-per-trillion(ppt)levels for trace gases such as methane(CH₄),acetylene(C₂H₂),carbon monoxide(CO),and so on.Additionally,prospects for future technological developments are also discussed in the concluding section.展开更多
In this paper,a series of calibration-free temperature measurement methods based on light-induced thermoelastic spectroscopy(LITES)are proposed for the first time.These techniques utilize the steady-state and transien...In this paper,a series of calibration-free temperature measurement methods based on light-induced thermoelastic spectroscopy(LITES)are proposed for the first time.These techniques utilize the steady-state and transient response characteristics of the quartz tuning fork(QTF),namely,the calibration-free LITES(CF-LITES)and calibration-free heterodyne LITES(CF-H-LITES)methods.Four methods,first harmonic(1f)difference signal to normalize the second harmonic(2f)fundamental signal(method Ⅰ,2f_(fund)/1f_(diff)),1f overtone signal to normalize the 2f fundamental signal(method Ⅱ,2f_(fund)/1f_(over)),1f heterodyne difference signal to normalize the 2f heterodyne fundamental signal(method Ⅲ,2f-H_(fund)/1f-H_(diff)),and 1f heterodyne overtone signal to normalize the 2f heterodyne fundamental signal(method Ⅳ,2f-H_(fund)/1f-H_(over)),for simultaneously detecting 1f and 2f within the frequency response range of the QTF are proposed to achieve calibration-free measurement.A self-designed T-shaped QTF with low fundamental and overtone frequencies was used to increase the energy accumulation time,thereby enhancing the sensor signal level.A 3-stage tube furnace was adopted to verify the performance of these 4 methods.Experimental results showed that the errors for the 4 methods were less than 4%,with a standard deviation below 11℃.Furthermore,the calibration-free method,which employs normalization of the 2f signal with the 1f signal,effectively mitigates the impact of laser beam jitter and power fluctuations on detection performance.A superior performance can be obtained by adopting the CF-H-LITES technique based on method Ⅳ.It not only has excellent detection performance but also reduces the measurement period to 4 s,which is about 5 times faster.This development shows substantial promise for expanding the application of the CF-LITES and CF-H-LITES techniques in harsh environments.展开更多
In this paper,a non-resonant quartz-enhanced photoacoustic spectroscopy(NR-QEPAS)sensor is reported for the first time,to the best of our knowledge.The non-resonant photoacoustic cell(PAC)serves as the region where th...In this paper,a non-resonant quartz-enhanced photoacoustic spectroscopy(NR-QEPAS)sensor is reported for the first time,to the best of our knowledge.The non-resonant photoacoustic cell(PAC)serves as the region where the photoacoustic effect occurs.NR-QEPAS offers several advantages,including flexible quartz tuning fork(QTF)positioning,frequencymatching-free operation,and simplified optical alignment.A self-designed T-head QTF was utilized as an acoustic wave transducer.The sound pressure characteristics of the non-resonant PAC were simulated using the finite element method.A near-infrared distributed feedback(DFB)diode laser with a wavelength of 1650.96 nm was selected as the excitation source.Methane(CH_(4))was chosen as the target gas to validate the designed sensor's performance.The experimental results showed that the designed non-resonant PAC worked in the plane wave state,and the sound pressure in the cavity was nearly uniform.The minimum detection limit(MDL)of the designed NR-QEPAS sensor for CH_(4)detection could be 1.09 ppm(1 ppm=10-6)when the average time was 760 s.展开更多
sensor based on light-induced thermoelastic spectroscopy(LITES)with a fiber-coupled multipass cell was demonstrated for carbon monoxide(CO)detection.The fiber-coupled structure has the merits of reducing optical inter...sensor based on light-induced thermoelastic spectroscopy(LITES)with a fiber-coupled multipass cell was demonstrated for carbon monoxide(CO)detection.The fiber-coupled structure has the merits of reducing optical interference and difficulty in optical alignment and increasing system robustness.A 1.57 nm continuous wave distributed feedback diode laser was used as the excitation source.A minimum detection limit of 9 ppm was obtained,and the calculated normalized noise equivalent absorption coefficient was 1.15×10^(-7)cm^(-1)•W•Hz^(-1/2).The reported CO-LITES sensor showed excellent linear concentration response and system stability.展开更多
基金supports from the National Natural Science Foundation of China(Grant Nos.62335006,62022032,62275065,and 62405078)Key Laboratory of Opto-Electronic Information Acquisition and Manipulation(Anhui University),Ministry of Education(Grant No.OEIAM202202)+2 种基金Fundamental Research Funds for the Central Universities(Grant No.HIT.OCEF.2023011)China Postdoctoral Science Foundation(Grant No.2024M764172)Heilongjiang Postdoctoral Fund(Grant No.LBH-Z23144).
文摘In this paper,a novel four-prong quartz tuning fork(QTF)was designed with enlarged deformation area,large prong gap,and low resonant frequency to improve its performance in laser spectroscopy sensing.A theoretical simulation model was established to optimize the design of the QTF structure.In the simulation of quartz-enhanced photoacoustic spectroscopy(QEPAS)technology,the maximum stress and the surface charge density of the four-prong QTF demonstrated increases of 11.1-fold and 15.9-fold,respectively,compared to that of the standard two-prong QTF.In the simulation of light-induced thermoelastic spectroscopy(LITES)technology,the surface temperature difference of the four-prong QTF was found to be 11.4 times greater than that of the standard QTF.Experimental results indicated that the C_(2)H_(2)-QEPAS system based on this innovative design improved the signal-to-noise-ratio(SNR)by 4.67 times compared with the standard QTF-based system,and the SNR could increase up to 147.72 times when the four-prong QTF was equipped with its optimal acoustic micro-resonator(AmR).When the average time of the system reached 370 s,the system achieved a MDL as low as 21 ppb.The four-prong QTF-based C_(2)H_(2)-LITES system exhibited a SNR improvement by a factor of 4.52,and a MDL of 96 ppb was obtained when the average time of the system reached 100 s.The theoretical and experimental results effectively demonstrated the superiority of the four-prong QTF in the field of laser spectroscopy sensing.
文摘Grooved tuning forks with hierarchical structures have become some of the most widely used piezoelectric quartz microelectromechanical system devices;however,fabricating these devices requires multi-step processes due to the complexity of etching of quartz,particularly in specific orientations of the crystal lattice.This paper proposes a one-step fabrication strategy that can form a complete hierarchical structure with only a single etching process using novel lithography patterns.The core principle of this strategy is based on the effect of the size of the groove patterns on quartz etching,whereby trenches of varying depths can be created in a fixed etching time by adjusting the width of the hard mask.Specifically,the device outline and grooved structure can be completed using a seamlessly designed etching pattern and optimized time.Furthermore,the etching structure itself influences the etching results.It was found that dividing a wide trench by including a wall to separate it into two narrow trenches significantly reduces the etching rate,allowing for predictable tuning of the etching rate for wider grooves.This effectively increases the usability and flexibility of the one-step strategy.This was applied to the manufacture of an ultra-small quartz grooved tuning fork resonator with a frequency of 32.768 kHz in a single step,increasing production efficiency by almost 45%and reducing costs by almost 30%compared to current methods.This has great potential for improving the productivity of grooved tuning fork devices.It can also be extended to the fabrication of other quartz crystal devices requiring hierarchical structures.
基金supported by the National Natural Science Foundation of China(Grant Nos.62335006,62275065,62022032,62405078,and 62505066)Open Subject of Hebei Key Laboratory of Advanced Laser Technology and Equipment(Grant No.HBKL-ALTE2025001)+2 种基金Heilongjiang Postdoctoral Fund(Grant No.LBH-Z23144 and LBH-Z24155)Natural Science Foundation of Heilongjiang Province(Grant No.LH2024F031)China Postdoctoral Science Foundation(Grant No.2024M764172).
文摘In this paper,a novel self-designed inverted-triangular lithium niobate tuning fork(LiNTF)was used to construct gas sensing system for the first time.The optimal ratio of the upper and lower boundaries of the inverted-triangular LiNTF is found by scanning through finite element analysis(FEA).The surface charge density and stress value of the inverted-triangular LiNTF are both higher than those of the standard quartz tuning fork(QTF).In the lithium niobate-enhanced photoacoustic spectroscopy(LiNPAS)sensing system,the 2f peak and signal-to-noise ratio(SNR)of the inverted-triangular LiNTF are 7.41 times and 5.89 times those of the standard QTF,respectively.After forming acoustic standing wave field with the acoustic micro-resonator(AmR),the LiNPAS system achieves an SNR 56.16 times higher than without the AmR.Based on Allan variance analysis,the system achieves a minimum detection limit(MDL)of 7.25 ppb with an averaging time of 800 seconds.In the light-induced thermoelastic spectroscopy(LITES)sensing system,the 2f peak and SNR of the inverted-triangular LiNTF are 7.82 times and 6.03 times those of the standard QTF,respectively.When the averaging time reaches 100 s,the MDL of the system is found to be 25.78 ppb.
文摘The micro quartz crystal tuning fork gyroscope is a new type of vibratory gyroscope. The gyroscope should be analyzed and simulated early in the design stage in order to offer reliable basis for design and to shorten the period of development. Thus the vibratory characteristics of the gyroscope is simulated with the finite element method of coupled field. The optimum exciting frequency and the factors which influence the gyroscope sensitivity are determined. The method for adjusting the frequency deviation between driving and detecting modes is also proposed.
文摘We present the fabrication and testing of a silicon carbide （SiC） balanced mass doublended tuning fork that survives harsh environments without compromising the device strain sensitivity and resolution bandwidth. The device features a material stack that survives corrosive environments and enables high-temperature operation. To perform hightemperature testing, a specialized setup was constructed that allows the tuning fork to be characterized using traditional silicon electronics. The tuning fork has been operated at 600°C in the presence of dry steam for short durations. This tuning fork has also been tested to 64 000 G using a hard-launch, soft-catch shock implemented with a light gas gun. However, the device still has a strain sensitivity of 66 Hz/μe and strain resolution of 0. 045 μe in a 10 kHz bandwidth. As such, this balanced-mass double-ended tuning fork can be used to create a variety of different sensors including strain gauges, accelerometers, gyroscopes, and pressure transducers. Given the adaptable fabrication process flow, this device could be useful to micro-electro-mechanical systems （MEMS） designers creating sensors for a variety of different applications.
基金This project is supported by National Natural Science Foundation of China(No.50275108).
文摘To enhance the coherence and reliability of the double-ended tuning fork(DETF)resonator,a measurement system of resonator vibration is presented to check its dynamic characteristics.Laser Doppler techniques are utilized and the relation between DETF vibration velocity and output current of photodetector is obtained.Resonator vibration equation is also analyzed and its driving power only depends on the direct current bias voltage and the amplitude of alternative voltage.Furthermore,a special resonator driving control circuit based on measurement is designed.The amplitude and frequency of circuit is controlled by a computer so that highly stable and strong driving signal can be output.Experiments on driving and measuring double-ended tuning fork have been done,The frequency of driving signal is 8 kHz and the peak-to-peak value of driving voltage is 140 V.Experimental results indicate resonator can be drived stably by driving control circuit and dynamic characteristics of DETF may be measured in real time.
基金supported in part by the National Key Research and Development Program of China (Grant No.2020YFB2008800)the Nanchang Institute for Microtechnology of Tianjin University。
文摘This paper is focused on electrode design for piezoelectric tuning fork resonators.The relationship between the performance and electrode pattern of aluminum nitride piezoelectric tuning fork resonators vibrating in the in-plane flexural mode is investigated based on a set of resonators with different electrode lengths,widths,and ratios.Experimental and simulation results show that the electrode design impacts greatly the multimode effect induced from torsional modes but has little influence on other loss mechanisms.Optimizing the electrode design suppresses the torsional mode successfully,thereby increasing the ratio of impedance at parallel and series resonant frequencies(R_(p)/R_(s))by more than 80%and achieving a quality factor(Q)of 7753,an effective electromechanical coupling coefficient(kt_(eff)^(2))of 0.066%,and an impedance at series resonant frequency(R_(m))of 23.6 kΩ.The proposed approach shows great potential for high-performance piezoelectric resonators,which are likely to be fundamental building blocks for sensors with high sensitivity and low noise and power consumption.
基金supported by the 11th Five-Year Plan Military Pre-study Foundation under Grand No. G17010801TX11030203
文摘This paper proposes an improved design of micromachined tuning fork gyroscope （M-TFG） to decouple the cross talk between driving and sensing directions better and to increase resolution. By employing dual-folds spring suspension, the drive mode and the sense mode are mechanically decoupled. Through careful layout design of the location of the dual-folds spring suspension and the drive combs, the mechanical coupling effect is further decreased by isolating the unwanted excitation from detection. The quality factor investigation demonstrates that high quality factor can be attained by using this structure, which can bring in accurate resolution. As a result, this design has the potential to accomplish low bias drift and accurate resolution for initial level applications.
文摘We have built an atomic force microscope using a quartz tuning fork as sensor. The excitation method we adopted, the electrical excitation, introduces stray capacitance into the signal-processing circuit. In this report, we demonstrated a simple but effective method to compensate for this parasitic capacitance by adding a compensator circuit consisting of an inverting amplifier and a capacitor. The capacitor is connected in series with the inverting amplifier and the compensator is connected in parallel with the quartz tuning fork. The resonance curve of the system measured after adding the homemade compensator resembles that of a pure RLC circuit, meaning that the stray capacitance is successfully eliminated. Furthermore, we tried to use our equipment to measure PDMS sample and got clean data. This system can be further combined with confocal microscope and diamond with NV defect to build scanning NV magnetometry.
基金National Natural Science Foundation of China(Grant Nos.62335006,62022032,62275065,and 61875047)Key Laboratory of Opto-Electronic Information Acquisition and Manipulation(Anhui University),Ministry of Education(Grant No.OEIAM202202)Fundamental Research Funds for the Central Universities(Grant No.HIT.OCEF.2023011).
文摘A highly sensitive light-induced thermoelectric spectroscopy(LITES)sensor based on a multi-pass cell(MPC)with dense spot pattern and a novel quartz tuning fork(QTF)with low resonance frequency is reported in this manuscript.An erbi-um-doped fiber amplifier(EDFA)was employed to amplify the output optical power so that the signal level was further enhanced.The optical path length(OPL)and the ratio of optical path length to volume(RLV)of the MPC is 37.7 m and 13.8 cm^(-2),respectively.A commercial QTF and a self-designed trapezoidal-tip QTF with low frequency of 9461.83 Hz were used as the detectors of the sensor,respectively.The target gas selected to test the performance of the system was acetylene(C2H2).When the optical power was constant at 1000 mW,the minimum detection limit(MDL)of the C2H2-LITES sensor can be achieved 48.3 ppb when using the commercial QTF and 24.6 ppb when using the trapezoid-al-tip QTF.An improvement of the detection performance by a factor of 1.96 was achieved after replacing the commer-cial QTF with the trapezoidal-tip QTF.
基金Project (No. 11551074) supported by the Science Research Fund of Heilongjiang Provincial Education Department,China
文摘This paper presents the design,fabrication,and characterization of a quartz tuning fork temperature sensor based on a new ZY-cut quartz crystal bulk acoustic wave resonator vibrating in a flexural mode.Design and performance analysis of the quartz tuning fork temperature sensor were conducted and the thermal sensing characteristics were examined by measuring the resonance frequency shift of this sensor caused by an external temperature.Finite element method is used to analyze the vibratory modes and optimize the structure of the sensor.The sensor prototype was successfully fabricated and calibrated in operation from 0 to 100 ℃ with the thermo-sensitivity of 70×10-6/℃.Experimental results show that the sensor has high thermo-sensitivity,good stability,and good reproducibility.This work presents a high-precision low-power temperature sensor using the comprehensive thermal characterization of the ZY-cut quartz tuning fork resonator.
基金supported by the National Natural Science Foundation of China(Nos.62335006,62022032,and 62275065)the Key Laboratory of Opto-Electronic Information Acquisition and Manipulation(Anhui University)+1 种基金Ministry of Education(No.OEIAM202202)the Fundamental Research Funds for the Central Universities(No.HIT.OCEF.2023011).
文摘A highly sensitive carbon dioxide(CO_(2))sensor based on light-induced thermoelastic spectroscopy(LITES)utilizing a selfdesigned low-frequency quartz tuning fork(QTF)and a fiber-coupled multipass cell(MPC)is reported in this paper.The QTF with a low resonant frequency of 8675 Hz and a high Q factor of 11,675.64 was used to improve its energy accumulation time and the sensor’s signal level.The MPC with the fiber-coupled structure and optical length of 40 m was adopted to significantly increase the gas absorbance and reduce the optical alignment difficulty as well as improve the robustness of the sensor system.A distributed feedback(DFB),near-infrared diode laser with an emission wavelength of 1.57μm was used as an excitation source.The experimental results showed that this CO_(2)-LITES sensor had an excellent linear response to CO_(2) concentrations.The minimum detection limitation(MDL)of this CO_(2)-LITES sensor was obtained to be 445.91 ppm,and it could be improved to 47.70 ppm(parts per million)when the integration time of the system reached 500 s.Further improvement methods for the detection performance of such sensors were also discussed.
基金supported by the National Natural Science Foundation of China(Nos.62335006,62275065,62022032,and 62405078)the Open Subject of Hebei Key Laboratory of Advanced Laser Technology and Equipment(No.HBKLALTE2025001)+2 种基金the Heilongjiang Postdoctoral Fund(Nos.LBH-Z23144 and LBH-Z24155)the Natural Science Foundation of Heilongjiang Province(No.LH2024F031)the China Postdoctoral Science Foundation(No.2024M764172)。
文摘In this Letter,a quartz-enhanced photoacoustic spectroscopy(QEPAS)gas sensor based on a single off-beam acoustic micro-resonator(AmR)and dual quartz tuning forks(QTFs)was demonstrated for the first time,to our knowledge.The sensor offers advantages of a compact sensing structure and high acoustic energy utilization efficiency.The key parameters of the designed off-beam AmR were optimized based on standing wave enhancement characteristics.Water vapor(H2O)in the environment was chosen as the target gas to investigate the sensor performance.Under identical experimental conditions,the reported sensor achieved 15.02 times improvement in detection sensitivity compared to the bare QTF-based sensor system,as well as a 1.53 times enhancement over the traditional off-beam QEPAS technique.
文摘A fully automated atomic force microscope(AFM)is presented.The mechanical motion of the AFM stage was controlled by three steppers.The fine motion of the AFM was controlled by an MCL one-axis piezo plate.A32.768kHz crystal tuning fork(TF)was used as the transducer with a probe attached.An acoustic sensor was used to measure the interactions between the probe and the sample.An SR850lock-in amplifier was used to monitor the TF signals.An additional lock-in amplifier was used to monitor the acoustic signal.A field programmable gate array(FPGA)board was used to collect the data in automatic mode.The main controller was coded with LabVIEW,which was in charge of Z-axis scan,signal processing and data visualization.A manual mode and an automatic mode were implemented in the controller.Users can switch the two modes at any time during the operation.This AFM system showed several advantages during the test operations.It is simple,flexible and easy to use.
基金National Natural Science Foundation of China(Grant No.62335006,62022032,62275065,and 61875047)Key Laboratory of Opto-Electronic Information Acquisition and Manipulation(Anhui University),Ministry of Education(Grant No.OEIAM202202)Fundamental Research Funds for the Central Universities(Grant No.HIT.OCEF.2023011).
文摘In this paper,a novel highly sensitive methane(CH_(4))and acetylene(C_(2)H_(2))dual-gas light-induced thermoelectric spectroscopy(LITES)sensor based on Lissajous space-division multiplexed(LSDM)technology and trapezoidal-head quartz tuning fork(QTF)detector was reported for the first time.A theoretical LSDM model was established on the basis of three-mirror astigmatic multi-pass cell(MPC)and it was used to design a pair of Lissajous spot patterns with optical path length to volume ratios(OPL/Vs)of 13.5 cm^(-2) and 13.3 cm^(-2),respectively.Two self-designed trapezoidal-head QTFs with low resonant frequencies of less than 10 kHz and quality factor of~12000 were adopted to enhance the detection ability.Two kinds of fiber amplifier,erbium doped fiber amplifier(EDFA)and Raman fiber amplifier(RFA),were combined to amplify the output power of two diode lasers to improve the excitation strength.After optimization,minimum detection limit(MDL)of 268.8 ppb and 91.4 ppb for real-simultaneous CH_(4) and C_(2)H_(2) sensing were obtained,respectively.When the integration time of the system were 150 s and 100 s,the MDLs could be improved to 54.8 ppb and 26.1 ppb,accordingly.Further improvement methods for such sensor were discussed.
基金supports from the National Natural Science Foundation of China(Grant No.62335006,62275065,62022032,62405078,and 62505066)Open Subject of Hebei Key Laboratory of Advanced Laser Technology and Equipment(HBKL-ALTE2025001)+2 种基金Heilongjiang Postdoctoral Fund(Grant No.LBH-Z23144 and LBH-Z24155)Natural Science Foundation of Heilongjiang Province(Grant No.LH2024F031)China Postdoctoral Science Foundation(Grant No.2024M764172).
文摘Gas sensing technology is widely applied in various fields,including environmental monitoring,industrial process control,medical diagnostics,safety warnings,and more.As a detection element,the quartz tuning fork(QTF)offers advantages such as high-quality factor(Q-factor),strong noise immunity,compact size,and low cost.Notably,its resonant characteristics significantly enhance system signal strength.Two spectroscopic techniques based on QTF detection,Quartz-enhanced photoacoustic spectroscopy(QEPAS)and light-induced thermoelastic spectroscopy(LITES),are currently research hotspots in the field of spectral sensing.This paper provides a comprehensive and detailed review and highlights pivotal innovations in these two QTF-based spectroscopic techniques.For QEPAS,these encompass high-power excitation methods,novel excitation sources,advanced QTF detection elements,and acoustic wave amplification strategies.Regarding LITES,the researches on optical cavity-enhanced approaches,modified QTF improvement mechanisms,integration with heterodyne demodulation technique,and combination with QEPAS were analyzed.These advances have enabled quartz-enhanced laser spectroscopy to achieve detection limits ranging from parts-per-billion(ppb)to parts-per-trillion(ppt)levels for trace gases such as methane(CH₄),acetylene(C₂H₂),carbon monoxide(CO),and so on.Additionally,prospects for future technological developments are also discussed in the concluding section.
基金supported by the National Natural Science Foundation of China(Grant Nos.62335006,62022032,62275065,62405078,and 61875047)the Key Laboratory of Opto-Electronic Information Acquisition and Manipulation(Anhui University),the Ministry of Education(Grant No.OEIAM202202)the Fundamental Research Funds for the Central Universities(Grant No.HIT.OCEF.2023011).
文摘In this paper,a series of calibration-free temperature measurement methods based on light-induced thermoelastic spectroscopy(LITES)are proposed for the first time.These techniques utilize the steady-state and transient response characteristics of the quartz tuning fork(QTF),namely,the calibration-free LITES(CF-LITES)and calibration-free heterodyne LITES(CF-H-LITES)methods.Four methods,first harmonic(1f)difference signal to normalize the second harmonic(2f)fundamental signal(method Ⅰ,2f_(fund)/1f_(diff)),1f overtone signal to normalize the 2f fundamental signal(method Ⅱ,2f_(fund)/1f_(over)),1f heterodyne difference signal to normalize the 2f heterodyne fundamental signal(method Ⅲ,2f-H_(fund)/1f-H_(diff)),and 1f heterodyne overtone signal to normalize the 2f heterodyne fundamental signal(method Ⅳ,2f-H_(fund)/1f-H_(over)),for simultaneously detecting 1f and 2f within the frequency response range of the QTF are proposed to achieve calibration-free measurement.A self-designed T-shaped QTF with low fundamental and overtone frequencies was used to increase the energy accumulation time,thereby enhancing the sensor signal level.A 3-stage tube furnace was adopted to verify the performance of these 4 methods.Experimental results showed that the errors for the 4 methods were less than 4%,with a standard deviation below 11℃.Furthermore,the calibration-free method,which employs normalization of the 2f signal with the 1f signal,effectively mitigates the impact of laser beam jitter and power fluctuations on detection performance.A superior performance can be obtained by adopting the CF-H-LITES technique based on method Ⅳ.It not only has excellent detection performance but also reduces the measurement period to 4 s,which is about 5 times faster.This development shows substantial promise for expanding the application of the CF-LITES and CF-H-LITES techniques in harsh environments.
基金supported by the National Natural Science Foundation of China(Nos.62335006,62275065,62022032,62405078,and 624B2050)the Key Laboratory of OptoElectronic Information Acquisition and Manipulation(Anhui University),Ministry of Education(No.OEIAM202202)+3 种基金the Fundamental Research Funds for the Central Universities(No.HIT.OCEF.2023011)the Heilongjiang Postdoctoral Fund(No.LBH-Z23144)the Natural Science Foundation of Heilongjiang Province(No.LH2024F031)the China Postdoctoral Science Foundation(No.2024M764172)。
文摘In this paper,a non-resonant quartz-enhanced photoacoustic spectroscopy(NR-QEPAS)sensor is reported for the first time,to the best of our knowledge.The non-resonant photoacoustic cell(PAC)serves as the region where the photoacoustic effect occurs.NR-QEPAS offers several advantages,including flexible quartz tuning fork(QTF)positioning,frequencymatching-free operation,and simplified optical alignment.A self-designed T-head QTF was utilized as an acoustic wave transducer.The sound pressure characteristics of the non-resonant PAC were simulated using the finite element method.A near-infrared distributed feedback(DFB)diode laser with a wavelength of 1650.96 nm was selected as the excitation source.Methane(CH_(4))was chosen as the target gas to validate the designed sensor's performance.The experimental results showed that the designed non-resonant PAC worked in the plane wave state,and the sound pressure in the cavity was nearly uniform.The minimum detection limit(MDL)of the designed NR-QEPAS sensor for CH_(4)detection could be 1.09 ppm(1 ppm=10-6)when the average time was 760 s.
基金This work was supported by the National Natural Science Foundation of China(Nos.62022032,61875047,and 61505041)Natural Science Foundation of Heilongjiang Province of China(No.YQ2019F006)+1 种基金Fundamental Research Funds for the Central UniversitiesFinancial Grant from the Heilongjiang Province Postdoctoral Foundation(No.LBH-Q18052).
文摘sensor based on light-induced thermoelastic spectroscopy(LITES)with a fiber-coupled multipass cell was demonstrated for carbon monoxide(CO)detection.The fiber-coupled structure has the merits of reducing optical interference and difficulty in optical alignment and increasing system robustness.A 1.57 nm continuous wave distributed feedback diode laser was used as the excitation source.A minimum detection limit of 9 ppm was obtained,and the calculated normalized noise equivalent absorption coefficient was 1.15×10^(-7)cm^(-1)•W•Hz^(-1/2).The reported CO-LITES sensor showed excellent linear concentration response and system stability.
