We demonstrate what is to our knowledge the first realization of an optical parametric amplifier in orientation-patterned GaAs amplifying the emission of a quantum-cascade laser (QCL) with a distributed-feedback (DFB) structure. We report a gain as high as 53 dB at 4.5 mum, in good agreement with theoretical calculations. The narrow spectral linewidth and the good beam quality of this source are imposed by the DFB-QCL, while high-peak-power emission is achieved through the parametric amplification. These characteristics are of valuable interest for long-range spectroscopy.
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http://dx.doi.org/10.1364/OL.35.000505 | DOI Listing |
Background: Visuospatial problems are one of the possible signs of Alzheimer's Disease (AD). Notably, various studies on eye movement in static image searches reveal that individuals with dementia fixate on fewer Areas of Interest (AoIs) for a significantly shorter duration than normal controls (CTLs). Building on prior works on speech and eye movement, in this study we examined word timestamps to infer each subject's focus of attention while describing the Cookie Theft picture.
View Article and Find Full Text PDFJ Dent
January 2025
Clinic of General-, Special Care- and Geriatric Dentistry, Center for Dental Medicine, University of Zurich, Zurich, Switzerland. Electronic address:
Objectives: The study aimed to assess the prevalence and nature of emotional expressions in care-dependent older adults using an automated face coding (AFC) software. By examining the seven fundamental emotions, the study sought to understand how these emotions manifest and their potential implications for dental care in this population.
Methods: Fifty care-dependent older adults' (mean-age: 78.
Ophthalmic Physiol Opt
January 2025
Department of Optometry and Vision Science, Hadassah Academic College, Jerusalem, Israel.
Purpose: Reliable assessment is critical for diagnosing and managing meibomian gland dysfunction. Multi-functional diagnostic devices, such as meibographers, streamline clinical workflows by integrating multiple ocular assessments. Ensuring reproducibility across examiners is vital for accurate diagnosis and monitoring of treatment.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Chemical Engineering, University of Mohaghegh Ardabili, Ardabil, Iran.
In this paper, we propose and theoretically investigate a novel multimode refractive index (MMRI) plasmonic optical sensor for detecting various brain cancer cells, leveraging the unique capabilities of split ring resonators (SRRs). The sensor, simulated using the finite-difference time-domain (FDTD) method, exhibits dual resonance modes in its reflection spectrum within the 1500 nm to 3500 nm wavelength range, marking a significant advancement in multimode plasmonic biosensing. Through detailed parametric analysis, we optimize critical dimensional parameters to achieve superior performance.
View Article and Find Full Text PDFJ Biomed Opt
December 2024
University of Kentucky, Department of Biomedical Engineering, Lexington, Kentucky, United States.
Significance: Cellular metabolism is highly dynamic and strongly influenced by its local vascular microenvironment, gaining a systems-level view of cell metabolism is essential in understanding many critical biomedical problems in a broad range of disciplines. However, very few existing metabolic tools can quantify the major metabolic and vascular parameters together in biological tissues with easy access.
Aim: We aim to fill the technical gap by demonstrating a point-of-care, easy-to-use, easy-to-access, rapid, systematic optical spectroscopy platform for metabolic and vascular characterizations on biological models to enable scientific discoveries to translate more efficiently to clinical interventions.
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