We demonstrate an unfolding displacement measurement method to overcome the aliasing problem of wavelength-comb-swept laser (WCSL). Compared to the conventional wavelength-swept laser (WSL), the WCSL exhibits an extended coherence length, owing to the narrowing spectral linewidth of the etalon filter. However, the aliasing interference signal induces an unexpected back-bounced phenomenon during displacement measurement because of the discretely distributed comb-like periodic spectra of the etalon filter. By using the dual-reference interferometry method, the back-bounced displacement measurement can be successfully unfolded to extend the measurement range by two times. In addition, we demonstrate a longer-range surface profiling image over 18 mm within the 200 mm of measurement range using a line-field beam of a parallel-swept source-optical coherence tomography system.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1364/OE.26.005789 | DOI Listing |
Phys Rev Lett
December 2024
National University of Singapore, Department of Physics, Singapore 117551.
We uncover emergent universality arising in the equilibration dynamics of multimode continuous-variable systems. Specifically, we study the ensemble of pure states supported on a small subsystem of a few modes, generated by Gaussian measurements on the remaining modes of a globally pure bosonic Gaussian state. We find that beginning from highly entangled, complex global states, such as random Gaussian states and product squeezed states coupled via a deep array of linear optical elements, the induced ensemble attains a universal form, independent of the choice of measurement basis: it is composed of unsqueezed coherent states whose displacements are distributed normally and isotropically, with variance depending on only the particle-number density of the system.
View Article and Find Full Text PDFJ Vis Exp
January 2025
Mechanical, Aerospace, and Biomedical Engineering, University of Tennessee;
Cardiovascular disease (CVD) is the leading cause of death in the United States. Damage in the cardiovascular system can be due to environmental exposure, trauma, drug toxicity, or numerous other factors. As a result, cardiac tissue and vasculature undergo structural changes and display diminished function.
View Article and Find Full Text PDFDeep learning has become an attractive tool for addressing the limitations of traditional digital image correlation (DIC). However, extending learning-based DIC methods to three-dimensional (3D-DIC) measurements is challenging due to the limited displacement estimation range, which cannot handle the large displacements caused by stereo-matching disparities. Besides, most of the existing learning-based DIC architectures lack prior information to guide displacement estimation, resulting in insufficient accuracy.
View Article and Find Full Text PDFUtilizing the periodic pixel configuration of the CCD/CMOS imaging sensor as the reference grating and the image of the real grating formed by the lens as the specimen grating, the CCD Moiré method directly outputs amplified Moiré fringes, facilitating high-resolution, full-field deformation measurement. Due to the amplification effect of CCD Moiré, even minor relative rotations of the two gratings can significantly affect Moiré imaging and introduce measurable errors. This paper mainly addresses the imaging and measurement challenges of in-plane rotation in the CCD Moiré method.
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 PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!