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Measurement of refrative index based on fiber Mach-Zehnder interference
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作者 谷瑾瑜 王冠军 +2 位作者 安永泉 刘星麟 张美芹 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2016年第2期106-109,共4页
In order to detect the refractive index of liquid with high precision,based on modular interference,Mach-Zehnder optical fiber refractive rate sensor was studied.Sensor structure is composed of ordinary single-mode fi... In order to detect the refractive index of liquid with high precision,based on modular interference,Mach-Zehnder optical fiber refractive rate sensor was studied.Sensor structure is composed of ordinary single-mode fiber and multimode fiber,according to the singlemode multimode singlemode sequence to fuse together,and the fused optical fiber is used to process the taper.As a result,the diameter of the sensing head is about 10μm.Experimental results show that,as liquid refractive index increases range from 1.33 to 1.35,the loss peak of the transmission spectrum will shift to long wave direction. 展开更多
关键词 optical fiber fusion optical fiber tapering Mach-Zehnder interference refractive index measurement optical fiber sensor
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Measurement of Refractive Index Ranging from 1.42847 to 2.48272 at 1064 nm Using a Quasi-Common-Path Laser Feedback System 被引量:1
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作者 徐玲 谈宜东 +1 位作者 张书练 孙利群 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第9期21-24,共4页
Wavelength 1064 nm is one of the most widely used laser wavelengths in industries and science. The high-precision measurement of the refractive index of optical materials at 1064 nm is significant for improving the op... Wavelength 1064 nm is one of the most widely used laser wavelengths in industries and science. The high-precision measurement of the refractive index of optical materials at 1064 nm is significant for improving the optical design. We study the direct measurement of refractive index at 1064nm of lasers, including cMcium fluoride (CaF2), fused silica and zinc selenide (ZnSe), whose refractive indices cover a large range from 1.42847 to 2.48272. The measurement system is built based on the quasi-common-path Nd:YAG laser feedback interferometry. The thickness can be measured simultaneously with the refractive index. The results demonstrate that the system has absolute uncertainties of ~10-5 and ~10-4 mm in refractive index and thickness measurement, respectively. 展开更多
关键词 In measurement of Refractive Index Ranging from 1.42847 to 2.48272 at 1064 nm Using a Quasi-Common-Path Laser Feedback System AOM
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The Approach of Compensation of Air Refractive Index in Thermal Expansion Coefficients Measurement Based on Laser Feedback Interferometry 被引量:2
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作者 郑发松 丁迎春 +2 位作者 谈宜东 林静 张书练 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第7期17-20,共4页
We present the thermal expansion coefficient (TEC) measurement technology of compensating for the effect of variations in the refractive index based on a Nd: YA G laser feedback system, the beam frequency is shifte... We present the thermal expansion coefficient (TEC) measurement technology of compensating for the effect of variations in the refractive index based on a Nd: YA G laser feedback system, the beam frequency is shifted by a pair of aeousto-optic modulators and then the heterodyne phase measurement technique is used. The sample measured is placed in a muffle furnace with two coaxial holes opened on the opposite furnace walls. The measurement beams hit perpendicularly and coaxially on each surface of the sample. The reference beams hit on the reference mirror and the high-refiectivity mirror, respectively. By the heterodyne configuration and computing, the influences of the vibration, distortion of the sample supporter and the effect of variations in the refractive index are measured and largely minimized. For validation, the TECs of aluminum samples are determined in the temperature range of 29-748K, confirming not only the precision within 5 × 10-7 K-1 and the accuracy within 0.4% from 298K to 448K but also the high sensitivity non-contact measurement of the lower reflectivity surface induced by the sample oxidization from 448 K to 748 K. 展开更多
关键词 In TEC The Approach of Compensation of Air Refractive Index in Thermal Expansion Coefficients measurement Based on Laser Feedback Interferometry
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Hybrid Long-Period Fiber Grating with Multimode Fiber Core for Refractive Index Measurement
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作者 邵敏 乔学光 +1 位作者 任学良 杨德兴 《Chinese Physics Letters》 SCIE CAS CSCD 2017年第11期41-44,共4页
A refractive index (RI) sensor based on hybrid long-period fiber grating (LPFG) with multimode fiber core (MMFC) is proposed and demonstrated. The surrounding RI can be determined by monitoring the separation be... A refractive index (RI) sensor based on hybrid long-period fiber grating (LPFG) with multimode fiber core (MMFC) is proposed and demonstrated. The surrounding RI can be determined by monitoring the separation between the resonant wavelengths of the LPFG and MMFC since the resonant wavelengths of the LPFG and MMFC will shift in opposite directions when the surrounding RI changes. Experimental results show that the sensor possesses an enhanced sensitivity of 526.92nm/RIU in the RI range of 1.387-1.394 RIU. The response to the temperature is also discussed. 展开更多
关键词 Hybrid Long-Period Fiber Grating with Multimode Fiber Core for Refractive Index measurement RIU
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Cascaded tilted fiber Bragg grating for enhanced refractive index sensing 被引量:2
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作者 Biqiang Jiang Zhixuan Bi +4 位作者 Shouheng Wang Tell Xi Kaiming Zhou Lin Zhang Jianlin Zhao 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第11期257-261,共5页
We proposed and experimentally demonstrated a cascaded tilted fiber Bragg grating(TFBG)for enhanced refractive index sensing.The TFBG is UV-inscribed in series in ordinary single-mode fiber(SMF)and reduced-diameter SM... We proposed and experimentally demonstrated a cascaded tilted fiber Bragg grating(TFBG)for enhanced refractive index sensing.The TFBG is UV-inscribed in series in ordinary single-mode fiber(SMF)and reduced-diameter SMF with the same tilt angle,and then excites two sets of superposed spectral combs of cladding modes.The cascaded TFBG with total length of 18 mm has a much wider wavelength range over 100 nm and narrower wavelength separation than that of a TFBG only in the SMF,enabling an enlarged range and a higher accuracy of refractive index measurement.The fabricated TFBG with the merits of enhanced sensing capability and temperature self-calibration presents great potentials in the biochemical sensing applications. 展开更多
关键词 tilted fiber Bragg grating fiber optics sensors refractive index measurement
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Experiments on self-excited oscillation in a thin-walled collapsible tube 被引量:1
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作者 Hai-Jun Wu Lai-Bing Jia Xie-Zhen Yin 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2015年第6期817-826,共10页
Self-excited oscillation in a collapsible tube is an important phenomenon in physiology. An experimental approach on self-excited oscillation in a thin-walled collapsi- ble tube is developed by using a high transmitta... Self-excited oscillation in a collapsible tube is an important phenomenon in physiology. An experimental approach on self-excited oscillation in a thin-walled collapsi- ble tube is developed by using a high transmittance and low Young's modulus silicone rubber tube. The elastic tube is manufactured by the method of centrifugal casting in our laboratory. An optical method for recording the evolution of the cross-sectional areas at a certain position along the longitudinal direction of the tube is developed based on the technology of refractive index matching. With the transparent tube, the tube law is measured under the static no-flow condition. The cross section at the middle position of the tube transfers from a quasi-circular configuration to an ellipse, and then to a dumbell-shape as the chamber pressure is increased. During the self-excited oscillation, two periodic self-excited oscillating states and one transitional oscillating state are identified. They all belong to the LU mode. These different oscillating states are related to the initial cross-sectional shape of the tube caused by the difference of the downstream transmural pressure. 展开更多
关键词 Collapsible tube Refractive index matching ·Cross-sectional area measurement· Self-excited oscillatingstates LU mode
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Random Raman Fiber Laser as a Liquid Refractive Index Sensor
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作者 Bing HAN Yuxi MA +1 位作者 Han WU Yong ZHAO 《Photonic Sensors》 SCIE EI CSCD 2024年第1期13-22,共10页
In this paper,a new concept of forward-pumped random Raman fiber laser(RRFL)-based liquid refractive index sensing is proposed for the first time.For liquid refractive index sensing,the flat fiber end immersed in the ... In this paper,a new concept of forward-pumped random Raman fiber laser(RRFL)-based liquid refractive index sensing is proposed for the first time.For liquid refractive index sensing,the flat fiber end immersed in the liquid can act as the point reflector for generating random fiber lasing and also as the sensing head.Due to the high sensitivity of the output power of the RRFL to the reflectivity provided by the point reflector in the ultralow reflectivity regime,the proposed RRFL is capable of achieving liquid refractive index sensing by measuring the random lasing output power.We theoretically investigate the effects of the operating pump power and fiber length on the refractive index sensitivity for the proposed RRFL.As a proof-of-concept demonstration,we experimentally realize high-sensitivity half-open short-cavity RRFL-based liquid refractive index sensing with the maximum sensitivity and the sensing resolution of-39.88W/RIU and 2.5075×10^(-5) RIU,respectively.We also experimentally verify that the refractive index sensitivity can be enhanced with the shorter fiber length of the RRFL.This work extends the application of the random fiber laser as a new platform for highly-sensitive refractive index sensing in chemical,biomedical,and environmental monitoring applications,etc. 展开更多
关键词 Fiber optic sensors refractive index measurements fiber lasers Rayleigh scattering stimulated Raman scattering
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Measurement of optical penetration depth and refractive index of human tissue 被引量:14
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作者 谢树森 李晖 李步洪 《Chinese Optics Letters》 SCIE EI CAS CSCD 2003年第1期44-46,共3页
Experimental techniques for measurement of optical penetration depth and refractive index of human tissue are presented, respectively. Optical penetration depth can be obtained from the measurement of the relative flu... Experimental techniques for measurement of optical penetration depth and refractive index of human tissue are presented, respectively. Optical penetration depth can be obtained from the measurement of the relative fluencc-depth distribution inside the target tissue. The depth of normal and carcinomatous human lung tissues irradiated with the wavelengths of 406.7, 632.8 and 674.4 nm in vitro are respectively determined. In addition, a novel simple method based on total internal reflection for measuring the refractive index of biotissue in vivo is developed, and the refractive indices of skin from people of different age, sex and skin color are measured. Their refractive indices are almost same and the average is 1.533. 展开更多
关键词 of in AS IS measurement of optical penetration depth and refractive index of human tissue
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Simultaneous measurement of refractive index and temperature using a microring resonator 被引量:1
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作者 林奈 姜澜 +2 位作者 王素梅 袁雷 陈强华 《Chinese Optics Letters》 SCIE EI CAS CSCD 2012年第5期66-69,共4页
An approach to the simultaneous optical ring resonators is proposed measurement of refractive-index (RI) and theoretically demonstrated. With and temperature changes using a liquid-core silica ring resonator as an e... An approach to the simultaneous optical ring resonators is proposed measurement of refractive-index (RI) and theoretically demonstrated. With and temperature changes using a liquid-core silica ring resonator as an example, two different-order whispering gallery modes (WGMs) might differ in not only RI but also temperature sensitivities. Thus, a second-order sensing matrix should be defined based on these WGMs to determine RI and temperature changes simultaneously. The analysis shows that the RI and temperature detection limits can be achieved on the order of 10.7 RI unit and 10-3 K at a wavelength of approximately 780 nm. 展开更多
关键词 In RI Simultaneous measurement of refractive index and temperature using a microring resonator
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Simultaneous refractive index and temperature measurements by using dual interference in an all-fiber Mach–Zehnder interferometer
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作者 闫旭 傅海威 +1 位作者 李辉栋 乔学光 《Chinese Optics Letters》 SCIE EI CAS CSCD 2016年第3期23-27,共5页
A Fourier analysis applied to the Mach-Zehnder interferometer (MZI) transmission spectrum for simultaneous refractive index (RI) and temperature measurements is proposed and experimentally demonstrated in this Let... A Fourier analysis applied to the Mach-Zehnder interferometer (MZI) transmission spectrum for simultaneous refractive index (RI) and temperature measurements is proposed and experimentally demonstrated in this Letter. In the fast Fourier transform (FFT) spectrum of the MZI transmission spectrum, several frequency components are generally observed, which means that the transmission spectrum of the MZI is formed by the superposition of some dual-mode interference (DMI) spectra, and each frequency component represents different core-cladding interferences. We can select some dominant frequency components in the FFT spectrum of the MZI transmission spectrum to take the inverse FFT (IFFT). Then, the corresponding DMI patterns can be obtained. Due to the shift of the wavelength of these DMI spectra with changes in the environmental parameters, we can use the coefficient matrix of these DMI spectra for multi-parameter sensing. In this Letter, two DMI patterns are separated from the resultant transmission spectrum of the MZI. As the RI and temperature change, the shifts of the two DMI patterns with respect to the RI and temperature will be observed. The sensitivities of the RI and temperature are -137.1806 nm/RIU (RI unit) and 0.0860 nm/℃, and -22.9955 nm/RIU and 0.0610 nm/℃ for the two DMIs. Accordingly, it can be used to simultaneously measure RI and temperature changes. The approach can eliminate the influence of multiple interferences and improve the accuracy of the sensor. 展开更多
关键词 RIU MZI DMI Simultaneous refractive index and temperature measurements by using dual interference in an all-fiber Mach Zehnder interferometer
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Refractive index measurement of dielectric samples using highly focused radially polarized light(Invited Paper)
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作者 Guadalupe López-Morales Victor-Manuel Rico-Botero +1 位作者 Rafael Espinosa-Luna Qiwen Zhan 《Chinese Optics Letters》 SCIE EI CAS CSCD 2017年第3期12-15,共4页
In this Letter, a refractive index measurement of a dielectric sample using highly focused radially polarized light is reported. Through imaging analysis of the optical field at the pupil plane of a high numerical ape... In this Letter, a refractive index measurement of a dielectric sample using highly focused radially polarized light is reported. Through imaging analysis of the optical field at the pupil plane of a high numerical aperture (NA) objective lens reflected by the sample under study, the Brewster angle is found. Employing a high NA objective lens allows the measurement of multiple angles of incidence from 0° to 64° in a single shot. The refractive index of the sample is estimated using the measured Brewster angle. The experimental results are compared with the theoretical images computed with the Fresnel theory, and a good agreement is obtained. 展开更多
关键词 high Refractive index measurement of dielectric samples using highly focused radially polarized light
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Continuous-wave terahertz diffraction tomography for measuring three-dimensional refractive index maps 被引量:2
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作者 Dayong Wang Xiaoyu Jin +3 位作者 Jie Zhao Yunxin Wang Lu Rong John J.Healy 《Chinese Optics Letters》 SCIE EI CAS CSCD 2021年第12期150-155,共6页
Three-dimensional(3D)refractive index(RI)distribution is important to reveal the object’s inner structure.We implemented terahertz(THz)diffraction tomography with a continuous-wave single-frequency THz source for mea... Three-dimensional(3D)refractive index(RI)distribution is important to reveal the object’s inner structure.We implemented terahertz(THz)diffraction tomography with a continuous-wave single-frequency THz source for measuring 3D RI maps.The off-axis holographic interference configuration was employed to obtain the quantitative scattered field of the object under each rotation angle.The 3D reconstruction algorithm adopted the filtered backpropagation method,which can theoretically calculate the exact scattering potential from the measured scattered field.Based on the Rytov approximation,the 3D RI distribution of polystyrene foam spheres was achieved with high fidelity,which verified the feasibility of the proposed method. 展开更多
关键词 diffraction tomography three-dimensional terahertz imaging three-dimensional reconstruction algorithm refractive index measurement
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Simultaneous quality improvement of the roughness and refractive index of SiC thin films
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作者 Gh.Sareminia H.Simchi +1 位作者 A.Ostovari L.Lavasanpour 《Journal of Semiconductors》 EI CAS CSCD 2012年第6期6-9,共4页
We deposite silicon carbide thin layers on cleaned Si(100) substrates using the plasma enhanced chemical vapor deposition method,and show that the RFTIR spectrum is periodic in the near and medium infrared ranges. I... We deposite silicon carbide thin layers on cleaned Si(100) substrates using the plasma enhanced chemical vapor deposition method,and show that the RFTIR spectrum is periodic in the near and medium infrared ranges. It is shown that both the deposition rate and the uniformity of the thin films are decreased by increasing the substrate temperature,and that the refractive index is increased by increasing the substrate temperature.This shows that there is a trade-off between the quality improvement of the uniformity and refractive index. 展开更多
关键词 SiC PECVD RFTIR thickness measurement refractive index
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