We present a continuous-wave fiber cavity ringdown (FCRD) pressure-sensing method based on frequency-shifted interferometry (FSI). Compared with traditional CRD or FCRD techniques, this FSI-FCRD scheme deduces pressure by measuring the decay rate of continuous light exiting the fiber ringdown cavity (RDC) in the spatial domain (i.e., the CRD distance), without the requirement for optical pulsation and fast electronics. By using a section of fiber with the buffer layer stripped in the fiber RDC as the sensor head, pressures were measured within the range from 0 to 10.4 MPa. The sensitivity of 0.02356/(km∙MPa) was obtained with a measurement error of 0.1%, and the corresponding pressure resolution was 0.05 MPa. It was found that the measurement sensitivity can be improved by enlarging the interaction length of the sensor head. The results show the proposed sensor has the advantages of simple structure, low cost, high sensitivity, and high stability in pressure detection.
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http://dx.doi.org/10.3390/s18041207 | DOI Listing |
Science
January 2025
Department of Electrical, Computer and Energy Engineering, University of Colorado Boulder, Boulder, CO, USA.
Optical frequency combs have enabled unique advantages in broadband, high-resolution spectroscopy and precision interferometry. However, quantum mechanics ultimately limits the metrological precision achievable with laser frequency combs. Quantum squeezing has led to significant measurement improvements with continuous wave lasers, but experiments demonstrating metrological advantage with squeezed combs are less developed.
View Article and Find Full Text PDFThe control of temporal noise of the pump could add an additional degree of freedom to manipulate the spectrum of continuous-wave (CW) pumped SC generation. In this paper, we experimentally tailor the CW-pumped supercontinuum (SC) generation in a cascaded Raman random fiber laser (CRRFL) based on a 1 µm pump with tunable temporal dynamics. The pump is based on a spectrally filtered ytterbium-doped random fiber laser (YRFL) seed laser, which can be amplified to a 10 W level with the tunable temporal noise.
View Article and Find Full Text PDFZhongguo Zhen Jiu
January 2025
College of TCM, Chongqing Medical University, Chongqing Key Laboratory of TCM for Prevention and Treatment of Metabolic Diseases, Chongqing 410007, China.
Objective: To assess the impacts of electroacupuncture (EA) on the gait, oxidative stress, inflammatory reaction, and protein degradation in the rats of denervated skeletal muscle atrophy, and explore the potential mechanism of EA for alleviating denervated skeletal muscle atrophy.
Methods: Forty male SD rats, 8 weeks old, were randomly assigned to a sham-surgery group, a model group, an EA group, and a p38 MAPK inhibitor group, with 10 rats in each group. The right sciatic nerve was transected to establish a rat model of denervated skeletal muscle atrophy in the model group, the EA group and the p38 MAPK inhibitor group.
Light Sci Appl
January 2025
State Key Laboratory of Luminescent Materials and Devices, and Guangdong Provincial Key Laboratory of Fiber Laser Materials and Applied Techniques, School of Materials Science and Engineering, South China University of Technology, 510640, Guangzhou, China.
Visible light microlasers are essential building blocks for integrated photonics. However, achieving low-threshold (μW), continuous-wave (CW) visible light lasing at room temperature (RT) has been a challenge because of the formidable requirement of population inversion at short wavelengths. Rare-earth (RE)-activated microcavities, featuring high-quality factor (Q) and small mode volume of whispering gallery modes, offer a great opportunity for achieving infrared-to-visible upconversion (UC) lasing.
View Article and Find Full Text PDFIn this Letter, we present an all-fiber bismuth (Bi)-doped germanosilicate fiber laser that is continuously tunable within the range of 1425-1475 nm, enabled by a tunable optical filter. A maximum output power of 86.4 mW was achieved at 1450 nm with a slope efficiency of 13.
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