Coherent LiDAR is a highly sensitive sensing technology with immunity to ambient light interference and the ability to measure velocity. It emits a wavelength-swept light signal and calculates the beat frequency between reference and sample light to measure the distances of targets. Recent advancements in signal modulation techniques, particularly quadrature detection, have effectively improved the detectable range of coherent LiDAR. In this study, we employ a 4x4 coupler for quadrature detection and incorporate dual reference paths with varying optical delays through an optical switch. This approach achieves a fourfold range extension compared to the conventional setup, while utilizing the same laser source and data acquisition process.
We suggest the multi-functions of nanodiamond (ND) as a neuritogenesis promoter and super-resolution imaging probe. Owing to the photoblinking property of ND, bioimages were visualized in super-resolution using the direct stochastic optical reconstruction microscopy process, which resolved the ambiguity in the distinction of nearby particles. In this study, NDs were endocytosed by HT-22 hippocampal neuronal cells and promoted a spontaneous neuritogenesis without any differentiation factor, which was visualized by NDs as super-resolution imaging probes without toxicity. In conclusion, it is suggested that ND has excellent neuritogenic capability and potential as a super-resolution neural imaging probe with its outstanding biocompatibility.
White light interferometry (WLI) is the 3D imaging sensor based on interferometry to obtain depth information by acquiring constructive interference. It allows a deep scanning range in high resolution while there are still limitations that lead to a low imaging speed and vibration from the mechanical movement. In this study, we resolved the vibration problem by isolating the depth scanning part in the tunable-path-difference source (TPDS) with a fiber stretcher from the interferometric measurement part. We also applied line-field interferometry to improve scanning speed and to image not only flat surfaces but also curved objects in variable fields of view.
KEYWORDS: Interferometers, Signal to noise ratio, Light, Telescopic pixel displays, Imaging systems, 3D image processing, 3D acquisition, Tomography, Stereoscopy, Interferometry
A novel scheme of white light interferometer (WLI) surface imaging system is demonstrated using a tunable-path-difference source (TPDS). TPDS is applied by adopting Mach–Zehnder interferometry to resolve the vibration noise, which the mechanical scanning has caused in the reference path of conventional WLI. Compared with WLI using comb-spacing-swept source (CSWS), WLI with TPDS is superior in terms of signal-to-noise ratio and total exposure of optical intensity into the camera. Through the improved performance, WLI with TPDS can successfully acquire 3D images at the micron scale and multi-layered tomographic information with fine detail.
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