We describe an algorithm to extract the complex refractive index of a material from broadband reflectance and transmittance measurements taken by spectrophotometers. The algorithm combines Kramers-Kronig analysis with an inversion of Fresnel's equations to provide a direct method of solving for the refractive index which is accurate, even for weakly absorbing materials, and easily applicable to radiative heat transfer calculations. The algorithm is validated by extracting the complex refractive index of polydimethylsiloxane between 0.25 μm and 100 μm and comparing against existing literature. We also discuss the importance of broadband optical properties to passive radiative cooling and details of the uncertainty analysis of the algorithm.
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http://dx.doi.org/10.1117/1.jpe.11.032105 | DOI Listing |
Light Sci Appl
January 2025
Institute for Photon Science and Technology, The University of Tokyo, Tokyo, Japan.
Light manipulation and control are essential in various contemporary technologies, and as these technologies evolve, the demand for miniaturized optical components increases. Planar-lens technologies, such as metasurfaces and diffractive optical elements, have gained attention in recent years for their potential to dramatically reduce the thickness of traditional refractive optical systems. However, their fabrication, particularly for visible wavelengths, involves complex and costly processes, such as high-resolution lithography and dry-etching, which has limited their availability.
View Article and Find Full Text PDFJ Mol Graph Model
January 2025
Department of Refraction, Baoji Aier Eye Hospital, Bao'ji, 721000, China. Electronic address:
In human eye, structural proteins, known as crystallins, play a crucial role in maintaining the eye's refractive index. These crystallins constitute majority of the total soluble proteins found in the eye lens. Among them, α-crystallins (α-CR) is one of the major components.
View Article and Find Full Text PDFBMJ Open
December 2024
Department of Ophthalmology & Clinical Centre of Optometry, Peking University People's Hospital, Beijing, China.
Objectives: To examine the ocular biometric parameters and predict the annual growth rate of the physiological axial length (AL) in Chinese preschool children aged 4-6 years old.
Methods: This retrospective cross-sectional study included 1090 kindergarten students (1090 right eyes) between the ages of 4 and 6 years from Pinggu and Chaoyang District, Beijing. Dioptre values were ascertained following cycloplegic autorefraction.
Asia Pac J Ophthalmol (Phila)
January 2025
Department of Ophthalmology, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Republic of Korea. Electronic address:
Myopia is rapidly escalating globally, especially in East and Southeast Asia, where its prevalence among younger populations reaches alarming levels of 80-90 %. This surge contributes to a myopia epidemic linked to several ocular complications, including glaucoma. As myopic individuals age, the risk of developing glaucoma increases, and an additional concern arises from the growing frequency of refractive surgeries among younger individuals, making precise optic nerve assessments critical before surgery.
View Article and Find Full Text PDFBiochim Biophys Acta Biomembr
January 2025
Department of Molecular Pathobiology, New York University, New York, NY, USA. Electronic address:
Inorganic polyphosphate (polyP) is a polymer that consists of a series of orthophosphates connected by high-energy phosphoanhydride bonds, like those found in ATP. In mammalian mitochondria, polyP has been linked to the activation of the mitochondrial permeability transition pore (mPTP). However, the details of this process are not completely understood.
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