We demonstrate that multiple exposures of a two-component holographic photopolymer can quadruple the refractive index contrast of the material beyond the single-exposure saturation limit. Quantitative phase microscopy of isolated structures written by laser direct-write lithography is used to characterize the process. This technique reveals that multiple exposures are made possible by diffusion of the chemical components consumed during writing into the previously exposed regions. The ultimate index contrast is shown to be limited by the solubility of fresh components into the multiply exposed region.
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http://dx.doi.org/10.1364/OL.43.001866 | DOI Listing |
Front Med (Lausanne)
December 2024
Chongqing Key Laboratory of Prevention and Treatment on Major Blinding Diseases, Chongqing Eye Institute, Chongqing Branch (Municipality Division) of National Clinical Research Center for Ocular Diseases, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
Background: This study aimed to comprehensively explore the thickness and topographic distributions of retinal vessel alterations of different myopic eyes by using swept-source OCT angiography (SS-OCTA).
Methods: One hundred myopes were included in this observational cross-sectional study. All participants underwent a series of ocular examinations of biometrical parameters, including spherical equivalent refraction (SER), axial length (AL), intraocular pressure (IOP), curvature radius (CR), and others.
Curr Res Food Sci
December 2024
Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, via G. Campi, 103, 41125 Modena, Italy.
Stable isotope analysis has become a valuable tool for studying food chain processes and verifying the authenticity and geographical origin of typical products. The analysis is particularly important for those foods with geographical indications, such as Aceto Balsamico Tradizionale di Modena labelled with the protected designation of origin mark (ABTM PDO) and Aceto Balsamico di Modena with the protected geographical indication (ABM PGI). Understanding how the aging process affects the isotopic composition of specific compounds in ABTM is important for distinguishing between traditional and non-traditional products, as well as for verifying their authenticity.
View Article and Find Full Text PDFHeliyon
December 2024
Department of Electrical and Electronic Engineering, Pabna University of Science and Technology, Pabna, 6600, Pabna, Bangladesh.
Methanol (CH₃OH) is a volatile, transparent, and toxic substance widely used in chemical substrates, antifreeze, and industrial applications. Ethanol (C₂H₅OH), in contrast, is commonly used in alcoholic beverages, as a fuel additive, and as an antiseptic. Differentiating between methanol and ethanol is critical due to the severe health risks associated with methanol ingestion, while ethanol is safe for consumption in moderation.
View Article and Find Full Text PDFNano Lett
January 2025
Second Physics Institute, University of Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany.
Conducting polymers have emerged as promising active materials for metasurfaces due to their electrically tunable states and large refractive index modulation. However, existing approaches are often limited to infrared operation or single-polymer systems, restricting their versatility. In this Letter, we present organic metasurfaces featuring dual conducting polymers, polyaniline (PANI) and poly(3,4-ethylenedioxythiophene) (PEDOT), to achieve contrasting dynamic optical responses at visible frequencies.
View Article and Find Full Text PDFBackground: Constituting ~0.5% of all NHS cataract operations, national provision of immediately sequential bilateral cataract surgery (ISBCS) is limited. Combining offering ISBCS within a novel one-stop see-and-treat (S&T) cataract pathway would offer patients the opportunity for two cataract operations in a single hospital visit.
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