A method is presented for reconstruction of the optical absorption coefficient from transmission near-infrared data with a cw source. As it is distinct from other available schemes such as optimization or Newton's iterative method, this method resolves the inverse problem by solving a boundary value problem for a Volterra-type integral-differential equation. It is demonstrated in numerical studies that this technique has a better than average stability with respect to the discrepancy between the initial guess and the actual unknown absorption coefficient. The method is particularly useful for reconstruction from a large data set obtained from a CCD camera. Several numerical reconstruction examples are presented.
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http://dx.doi.org/10.1364/josaa.23.002388 | DOI Listing |
Anal Chem
January 2025
Key Laboratory of Nondestructive Test (Ministry of Education), Nanchang Hangkong University, Nanchang 330063, China.
Off-axis integrated cavity output spectroscopy (OA-ICOS) allows the laser to be reflected multiple times inside the cavity, increasing the effective absorption path length and thus improving sensitivity. However, OA-ICOS systems are affected by various types of noise, and traditional filtering methods offer low processing efficiency and perform limited feature extraction. Deep learning models enable us to extract important features from large-scale, complex spectral data and analyze them efficiently and accurately.
View Article and Find Full Text PDFBiomaterials
January 2025
Lab of Molecular Imaging and Translational Medicine (MITM), Engineering Research Center of Molecular and Neuro Imaging, Ministry of Education, School of Life Science and Technology, Xidian University & International Joint Research Center for Advanced Medical Imaging and Intelligent Diagnosis and Treatment, Xi'an, Shaanxi, 710126, China. Electronic address:
The secondary near-infrared region (NIR-II) fluorescence imaging-guided photothermal therapy (PTT) offers a noninvasive and light-controllable treatment option for deep-seated cancers. However, the development of NIR-II photothermal agents (NIR-II PTAs) that possess the desired properties of high molar absorption coefficient (ε), fluorescence quantum yield (QY), and photothermal conversion efficiency (PCE) remain a challenge due to the contradiction between radiative and nonradiative processes. Herein, we propose a novel side-chain heteroatom substitution engineering strategy to simultaneously enhance ε, QY, and PCE by modifying the molecular planarity.
View Article and Find Full Text PDFNanomedicine (Lond)
January 2025
Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, China.
Photodynamic therapy (PDT) involves the activation of photosensitizers (PSs) by visible laser light at the target site to catalyze the production of reactive oxygen species, resulting in tumor cell death and blood vessel closure. The efficacy of PDT depends on the PSs, the amount of oxygen, and the intensity of the excitation laser. PSs have been extensively researched, and great efforts have been made to develop an ideal photosensitizer.
View Article and Find Full Text PDFHigh-resolution optical diagnostics in the short wavelength infrared (SWIR II) region have gained significant attention in medical research, showing great potential for tissue spectroscopy and visualization due to the region's low water absorption and scattering coefficients. However, high-beam-quality sources covering an entire spectral range are limited. This paper presents the development of a femtosecond Cr:ZnSe laser with a 2.
View Article and Find Full Text PDFThe intrinsic spontaneous and piezoelectric polarizations of GaN lead to the formation of triangular wells and barriers, resulting in the manifestation of chaotic transport models in GaN quantum well intersubband transition (ISBT) infrared detectors and giving rise to various adverse effects. The APSYS software was utilized to construct a novel GaN quantum well ISBT infrared detector in this study. By endeavoring to modify the quantum well structure, our objective was to precisely adjust the energy level of the first excited state (E1) to align with the apex of the triangular barrier.
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