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Absorption (electromagnetic radiation)

About: Absorption (electromagnetic radiation) is a research topic. Over the lifetime, 76674 publications have been published within this topic receiving 1381221 citations.


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Journal ArticleDOI
TL;DR: These experiments demonstrated that only a portion of the fatty acids that are esterified with the /3 position of the dietary triglycerides undergo hydrolysis during the processes of digestion and absorption, and it is possible to elucidate the composition of the lipids that are absorbed, the way they arise by enzymatic Hydrolysis, and how they are subsequently resynthesized into the triglycerides that are found in the lymph.

301 citations

Journal ArticleDOI
TL;DR: It is demonstrated experimentally that two-dimensional arrays of sharp convex grooves in gold ensure efficient (>87%) broadband (450-850 nm) absorption of unpolarized light, reaching an average level of 96%.
Abstract: Plasmonic effects can turn reflective metals into strong absorbers, although this is usually realized within narrow wavelength ranges near resonances. Using arrays of ultra-sharp convex grooves, Sondergaard et al. show that nonresonant absorption can lead to effective broadband light absorption.

301 citations

Journal ArticleDOI
TL;DR: In this article, a method to compensate for the effect of acoustic absorption on the measured time domain signals is described, where the reconstruction is regularized by filtering the absorption and dispersion terms in the spatial frequency domain using a Tukey window.
Abstract: The reconstruction of photoacoustic images typically neglects the effect of acoustic absorption on the measured time domain signals. Here, a method to compensate for acoustic absorption in photoacoustic tomography is described. The approach is based on time-reversal image reconstruction and an absorbing equation of state which separately accounts for acoustic absorption and dispersion following a frequency power law. Absorption compensation in the inverse problem is achieved by reversing the absorption proportionality coefficient in sign but leaving the equivalent dispersion parameter unchanged. The reconstruction is regularized by filtering the absorption and dispersion terms in the spatial frequency domain using a Tukey window. This maintains the correct frequency dependence of these parameters within the filter pass band. The method is valid in one, two and three dimensions, and for arbitrary power law absorption parameters. The approach is verified through several numerical experiments. The reconstruction of a carbon fibre phantom and the vasculature in the abdomen of a mouse are also presented. When absorption compensation is included, a general improvement in the image magnitude and resolution is seen, particularly for deeper features.

301 citations

Journal ArticleDOI
TL;DR: In this paper, a theory of the colloid band based upon the free electron model of the alkali metal and Mie's theory of absorption of light by conducting spheres is presented, which makes assertions concerning the integrated absorption, maximum absorption, band width, and band position which are compared with experiment.
Abstract: The thermal transformation of $F$ centers into colloid has been observed in NaCl. The transformation occurs with constant integrated absorption cross section. The shape of the band depends upon the temperature at which the colloid is formed. A theory of the colloid band based upon the free electron model of the alkali metal and Mie's theory of the absorption of light by conducting spheres is presented. The theory makes assertions concerning the integrated absorption, maximum absorption, band width, and band position which are compared with experiment.

300 citations

Journal ArticleDOI
TL;DR: In this paper, an elementary empirical model for the distribution of electronic states of an amorphous semiconductor is presented, and the functional form of the optical absorption spectrum is determined, focusing on the joint density of states function, which dominates the absorption spectrum over the range of photon energies.
Abstract: An elementary empirical model for the distribution of electronic states of an amorphous semiconductor is presented. Using this model, we determine the functional form of the optical absorption spectrum, focusing our analysis on the joint density of states function, which dominates the absorption spectrum over the range of photon energies we consider. Applying our optical absorption results, we then determine how the empirical measures commonly used to characterize the absorption edge of an amorphous semiconductor, such as the Tauc gap and the absorption tail breadth, are related to the parameters that characterize the underlying distribution of electronic states. We, thus, provide the experimentalist with a quantitative means of interpreting the physical significance of their optical absorption data.

300 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2022185
20213,106
20202,866
20192,953
20182,876
20172,679