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Imagine that instead of viewing an image through a lens, you look through a kaleidoscope that focuses invisible light to obtain a new range of colors. The photon, the ephemeral messenger of light, usually appears alone, but here it appears in a duet, which is the basis of two-photon . This is an extraordinary phenomenon in which the , instead of perceiving traditional light, receives pulses of infrared lasers, the gateway to the invisible world.

However, the key to this is measuring the brightness of two-photon stimuli, which until now was only possible for . ICTER scientists have made a breakthrough and determined the luminance value for infrared using photometric units (cd/m2). Thanks to this approach, it is possible to link the luminance of two-photon stimuli to a new physical quantity related to perceived brightness: the two-photon retinal illumination.

Research—conducted by scientists from the International Centre for Eye Research (ICTER) with the participation of Ph.D. student Oliwia Kaczkoś, Ph.D. Eng. Katarzyna Komar and Prof. Maciej Wojtkowski—has shown that the luminance of a two-photon stimulus can reach almost 670 cd/m2 in the safe range of laser power for the eye.

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Radio frequency (RF) and microwave power measurements are widely used to support applications across space, defense, and communication. These precise measurements enable engineers to accurately characterize waveforms, components, circuits, and systems.

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Fine tuning an experimental setup improved a detector’s sensitivity to neutrinos and perhaps eventually dark matter—two difficult-to-measure forms of matter which hold great importance for understanding particle physics and experimental cosmology. The University-of-Michigan-led study is published in Physical Review D.

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The polarization of light finds practical application in physics and chemistry through the optical activity phenomenon, where polarimeters play a crucial role. This research builds on the improvised polarimeter designed by Kvittingen and Sjursnes, implemented with relevant modifications, to measure optical rotations of over-the-counter ascorbic acid samples. The study aims to assess the purity of two brands of ascorbic acid through polarimetry, comparing the calculated specific rotation with the literature values and supplementing the characterization with melting point determination. The constructed polarimeter, assembled using Lego bricks, provides an affordable alternative for educational purposes, addressing the challenges observed in the accessibility of commercial polarimeters for classroom demonstrations. The methodology encompasses pre-experiment steps involving polarimeter construction, the experiment utilizing polarimetry and complementary melting point determination, and post-experiment analysis to determine specific rotation from the measured optical rotations. Results indicate that Brand X exhibited specific rotations close to theoretical values, inferring high purity. Conversely, Brand Y shows significant deviations, suggesting potential impurities. These conclusions are supported by melting point data. The comprehensive approach combining polarimetry and melting point determination enhances the reliability of purity assessments, showcasing the effectiveness of the improvised polarimeter in practical applications.

R J M Felicidario and R M delos Santos 2024 J. Phys.: Conf. Ser. 2,871 012009.

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Physicists at the Max Planck Institute for Dynamics and Self-Organization (MPI-DS) have investigated to which extent a piece of music can evoke expectations about its progression. They were able to determine differences in how far compositions of different composers can be anticipated. In total, the scientists quantitatively analyzed more than 550 pieces from classical and jazz music.

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Nuclear fusion could be an ideal solution to mankind’s energy problem, guaranteeing a virtually limitless source of power without greenhouse gas emissions. But there are still huge technological challenges to overcome before getting there, and some of them have to do with materials.

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Science can be difficult to explain to the public. In fact, any subfield of science can be difficult to explain to another scientist who studies in a different area. Explaining a theoretical science concept to high school students requires a new way of thinking altogether.

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In a paper published in Chaos, researchers from Sergio Arboleda University in Bogotá, Colombia, and the Georgia Institute of Technology in Atlanta used an electrophysiological computer model of the heart’s electrical circuits to examine the effect of the applied voltage field in multiple fibrillation-defibrillation scenarios. They discovered far less energy is needed than is currently used in state-of-the-art defibrillation techniques.

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