We present a double-sideband suppressed-carrier (DSB-SC) technique achieved by an optical balanced detection approach for measuring small vibrations. The baseband signal is recovered by demodulating the DSB-SC signal with a self-mixing approach without local oscillator, which is usually required in coherent detection. The achievement of carrier suppression and vibration measurement is experimentally demonstrated, and the result closely agrees with the theoretical predictions.
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http://dx.doi.org/10.1364/AO.52.005773 | DOI Listing |
The rigid Fabry-Pérot (F-P) cavity has emerged as the preferred core sensing component for optical pressure, vibration, and acoustic sensing in harsh environments, owing to its high reliability and structural stability. However, due to the inadequate temperature resistance of the optical dielectric film, maintaining a high level of precision in the rigid F-P cavity at elevated temperatures proves to be challenging. Volume Bragg grating (VBG) is a three-dimensional optical element modified by a femtosecond laser within a transparent glass medium to create a periodic refractive index distribution.
View Article and Find Full Text PDFDistributed acoustic sensing (DAS) is a technology that uses optical fiber as a sensing unit to detect external vibration signals. Due to the high resolution and high sensitivity of DAS, it has great application potential in the detection of vibration events. However, high detection performance will bring limitations to DAS in multi-source detection.
View Article and Find Full Text PDFDue to its simplicity, low cost, safety, and high precision, the fiber displacement interferometer has emerged as a highly promising and feasible method for measuring shock-induced vibrations. However, the harsh environments associated with such shocks pose significant challenges, including the need for resistance to fluctuations in light intensity, immunity to disturbances in the transmission fiber, and the capacity to conduct large-range, high-speed bidirectional measurements. To our knowledge, no existing methods adequately address all these requirements.
View Article and Find Full Text PDFElectric-field oscillations are now experimentally accessible in the THz-to-PHz frequency range. Their measurement delivers the most comprehensive information content attainable by optical spectroscopy - if performed with high sensitivity. Yet, the trade-off between bandwidth and efficiency associated with the nonlinear mixing necessary for field sampling has so far strongly restricted sensitivity in applications such as field-resolved spectroscopy of molecular vibrations.
View Article and Find Full Text PDFHum Mov Sci
January 2025
Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Japan.
Lumbar motor control is an important factor for the prevention and improvement of low back pain and the enhancement of sports performance. Interventions for lumbar motor control are complex and difficult; however, training with whole-body vibrations has the potential to be simple and effective. Therefore, this study aimed to verify the effects of 4 weeks of trunk training with whole-body vibrations on each component of lumbar motor control.
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