- 标题
- 摘要
- 关键词
- 实验方案
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A Simple, High Sensitive Fiber Optic Microphone Based on Cellulose Triacetate Diaphragm
摘要： We present a high sensitive fiber-optic microphone (FOM) with a wide measuring range based on a cellulose triacetate diaphragm in this work. The average signal-to-noise ratio (SNR) of the proposed FOM is measured 50.86 dB in at the frequency range of 100 Hz–20 kHz. In the same spectrum range, the highest SNR for the 2-kHz frequency under 103.16 mPa acoustic pressure is measured at 72.20 dB with 2 Hz resolution bandwidth, which corresponds to a noise-limited minimum detectable acoustic pressure level of 17.91 μPa/(cid:2)Hz. The proposed sensor has advantages of high sensitivity, low cost, and easy fabrication. According to the assessments based on the obtained results, the FOM can be used for medical spectroscopy, imaging applications, and for long-distance listening and voice recognition in the military-public security.
关键词： Fabry–Perot,polymer diaphragm,fiber-optic microphone
更新于2025-09-04 15:30:14
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Strong coupling of a two-dimensional electron ensemble to a single-mode cavity resonator
摘要： We investigate the regime of strong coupling of an ensemble of two-dimensional electrons to a single-mode cavity resonator. In particular, we realize such a regime of light-matter interaction by coupling the cyclotron motion of a collection of electrons on the surface of liquid helium to the microwave field in a semiconfocal Fabry-Pérot resonator. For the corotating component of the microwave field, the strong coupling is pronouncedly manifested by the normal-mode splitting in the spectrum of coupled field-particle motion. We present a complete description of this phenomenon based on classical electrodynamics, as well as show that the full quantum treatment of this problem results in mean-value equations of motion that are equivalent to our classical result. For the counterrotating component of the microwave field, we observe a strong resonance when the microwave frequency is close to both the cyclotron and cavity frequencies. We show that this surprising effect, which is not expected to occur under the rotating-wave approximation, results from the mixing between two polarization components of the microwave field in our cavity.
关键词： microwave field,classical electrodynamics,cavity resonator,normal-mode splitting,two-dimensional electrons,rotating-wave approximation,Fabry-Pérot resonator,strong coupling,quantum treatment,cyclotron motion
更新于2025-09-04 15:30:14
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Real-time temperature sensor based on in-fiber Fabry-Perot interferometer embedded in a resin
摘要： A simple to fabricate, cost-effective, robust, and highly accurate fiber optic temperature sensor is proposed and experimentally demonstrated. The sensor head consists of an in-fiber Fabry-Perot interferometer (FFPI) embedded in a mold made of a polyester resin. FFPI, which in general present good strain sensitivity and low temperature sensitivity, was assembled by splicing a microsegment of capillary fiber (CF) of 14.66 μm between two single-mode fibers (SMFs). The reflected spectrum of the FFPI exhibited a single interference dip within a span of 80 nm. The dimensions of the resin mold can be modified by changing the ambient temperature, which in turn changes the length of the FFPI air-cavity. The dip of the reflected spectrum is shifted towards shorter (larger) wavelengths when external temperature is decreased (increased). The large free spectral range (FSR) allowed to monitor the temperature changes by either a wavelength or an intensity interrogation scheme. Using a laser and an optical power meter it was possible to demonstrate a real-time temperature sensor with a sensitivity of -60.79 nW/oC and a resolution of 0.5 oC, in the range of 10-30 oC. We believe that the practicality of this real-time sensor can be very attractive for environmental sensing application.
关键词： Fabry Perot interferometer,Fiber optic sensor,Strain sensor,Polymers
更新于2025-09-04 15:30:14
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Simultaneous measurements of temperature and pressure with a dual-cavity Fabry-Perot sensor
摘要： A fiber-optic dual-cavity Fabry-Perot interferometric sensor for the simultaneous measurement of temperature and pressure is proposed and experimentally demonstrated. The sensor cascades a fiber-optic intrinsic Fabry–Perot interferometer (IFPI) and an extrinsic Fabry–Perot interferometer (EFPI). The IFPI is used as the temperature sensor and the EFPI is used as the pressure sensor. The pressure sensor is based on a diaphragm-free structure, and can work stably at high temperature. Two optical path differences are interrogated simultaneously by using the fast Fourier transform-based white-light interferometry and the peak-to-peak method. Experimental results show that the proposed sensor exhibits a temperature sensitivity of 29.63 nm/°C within the temperature range of 40-1100 °C, and a pressure sensitivity of 1465.8 nm/MPa within the pressure range of 0-10 MPa at the room temperature.
关键词： pressure measurement,femtosecond laser micromachining,fiber optics sensors,Fabry-Perot interferometers,temperature measurement
更新于2025-09-04 15:30:14
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Investigation on the Thermo-Optic Coefficient of Silica Fiber Within a Wide Temperature Range
摘要： In this paper, the thermo-optic coef?cient of silica ?ber is analyzed and measured within a wide temperature range of 0–1200 °C for the ?rst time. To obtain the thermo-optic coef?cient, experiments were carried out by using ?ber optic extrinsic Fabry–Perot interferometers (EFPIs) embedded in silica ?ber. The optical cavity lengths of the EFPIs were measured with white-light interferometry. The experimental results show that the ?rst and second orders of the thermo-optic coef?cient are 1.090 × 10?5/°C and 1.611 × 10?9/°C2, respectively. The quadratic model for the temperature dependence of the basic optical parameter, the refractive index, is rigorous within a wide temperature range. Furthermore, this paper also provides a temperature calibration method for extrinsic Fabry–Perot interferometric temperature sensors. The temperatures measured by the sensors are in excellent agreement with those measured by the reference thermocouple. Hence, this calibration method is promising for temperature sensors with a wide working temperature range.
关键词： thermo-optic coef?cient,Fabry-Perot interferometers,silica ?ber
更新于2025-09-04 15:30:14
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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - Wideband High-Gain Circularly-Polarised Antenna based on Fabry-Perot Concept and a Conical Horn
摘要： A novel wideband high-gain circularly-polarised (CP) antenna is presented in this paper. A hybrid design based on Fabry-Perot cavity and a short conical horn is applied to a small CP slot-fed patch antenna for wideband and high-gain operation. Simulations and experiments are conducted to validate the design and a good agreement is obtained. The measurements of the antenna prototype show a 3-dB axial ratio bandwidth of 12% and a peak gain of 16.3 dBi.
关键词： conical horn,wideband,circular polarisation,high gain,Fabry-Perot resonator antenna
更新于2025-09-04 15:30:14
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High-Gain Fabry-Perot Antennas with Wideband Low Monostatic RCS Using Phase Gradient Metasurface
摘要： The design of two high-gain Fabry-Perot (F-P) antennas with wideband low monostatic radar cross section (RCS) is presented in this paper. Firstly, a phase gradient metasurface (PGM) without lossy layer is used to realize in-band RCS reduction and high aperture efficiency simultaneously. The simulated results show that its peak gain is 19.2 dBi and a high aperture efficiency of 58.6% is achieved. By utilizing the PGM structure, the monostatic RCS is reduced from 7GHz to 11GHz and the in-band co-polarization RCS is reduced by 13.1 dB. After that, a PGM with metamaterial absorber (MA) is designed to broaden the bandwidth of RCS reduction. A prototype antenna is fabricated and measured. The peak gain of 17.9 dBi is obtained and the monostatic RCS is reduced in a wider frequency band of 7GHz to 15GHz.
关键词： radar cross section reduction (RCSR),Fabry-Perot antenna,phase gradient metasurface (PGM),high gain,in-band RCSR
更新于2025-09-04 15:30:14
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Fabrication of FP-cavity-based monolithic full-color filter arrays using a template-confined micro-reflow process
摘要： Fabry-Perot (FP) resonators are of great interest for various applications due to their high stability, environmental friendliness and chemical inertia. However, it is still technically challenging to obtain compact monolithic MDM-based color filter array (CFA) because of the difficulty in achieving microscale-pixelated stepwise dielectric films with designed thickness. In this work, we proposed a template-confined thermal reflow approach to fabricate monolithic CFA based on silver-polymethyl methacrylate-silver (Ag-PMMA-Ag) sandwich configuration. Via template-confined thermal reflow of periodic PMMA nanogratings with different filling density, the thickness of PMMA dielectric layer in each pixel can be independently controlled, enabling the spectral tunability across the whole visible light region with high transmission efficiency and narrow linewidth. Compared to conventional multiple deposition technique, the approach we proposed is able to control the thickness of dielectric film via a single exposure step and can be potentially applied in high-throughput production by combining nanoimprint lithography.
关键词： micro-reflow,monolithic stepwise dielectric layer,PMMA,color filter array,Fabry-Perot resonator
更新于2025-09-04 15:30:14
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Quasi-Distributed Fabry-Perot Optical Fibre Sensor for Temperature Measurements
摘要： This paper presents a simulation and an experimental quasi-distributed Fabry–Perot optical fibre sensor for temperature measurements implemented on a serial array using a combined frequency division multiplexing and wavelength division multiplexing arrangement. Quasi-distributed fibre sensors have been of great interest in the industry for the monitoring of power transformers, jet engines, and furnaces. This paper is aimed at providing theoretical results for a quasi-distributed sensor system made of 25 local sensors imprinted on a serial array of the single mode fibre whereby the local sensors are of weak reflectivity. In addition, a sensor system of nine quasi-distributed local sensors is experimentally tested and a sensitivity of 10 pm/oC and a resolution of 0.125°C are obtained. Its higher resolution, higher spatial distribution, and ability to measure temperature at different points simultaneously make it a very attractive temperature sensor.
关键词： Fabry-Perot,resolution,weak reflectivity,sensitivity
更新于2025-09-04 15:30:14
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Performance comparison of Fabry-Perot and Mach-Zehnder interferometers for Doppler lidar based on double-edge technique
摘要： Compared with dual-channel Fabry-Perot interferometer (DFPI), dual-channel Mach-Zehnder interferometer (DMZI) is a new frequency discriminator for Doppler wind lidar based on double-edge detection. The double-edge frequency discrimination systems based on DFPI and DMZI in the wind lidar system are designed, respectively, and the detection principle is analyzed theoretically. Under certain simulation conditions, performances such as line-of-sight (LOS) wind velocity measurement sensitivities, signal-to-noise ratios (SNR) and LOS wind velocity measurement errors of both DFPI and DMZI systems are simulated and compared based on the U.S. standard atmospheric model. The simulation results show that for 1064nm aerosol system, the LOS wind velocity measurement sensitivity of the DMZI system is lower than that of DFPI system and the error is higher than that of DFPI system with the same dynamic wind velocity measurement range. Nevertheless, for 355nm atmospheric molecular system, DMZI system provides a factor of 1.33 times lower error in the LOS wind velocity than that of DFPI with an altitude of 30 km and the LOS wind velocity of 200m/s. Furthermore, in the LOS wind velocity range of -200m/s~+200m/s, the measurement error of DMZI system hardly increases with the increasing of wind speed. Therefore, the results of this study not only provide guidance for the selection of discriminators, but also provide theoretical support for the application of DMZI in the double-edge detection of atmospheric molecular lidar.
关键词： dual-channel Fabry-Perot interferometer,Doppler lidar,wind velocity measurement,dual-channel Mach-Zehnder interferometer,double-edge detection
更新于2025-09-04 15:30:14