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An innovative planar spoof plasmonic neural network (SPNN) platform capable of directly detecting and processing terahertz (THz) electromagnetic signals has been unveiled by researchers at City University of Hong Kong (CityUHK) and Southeast University in Nanjing.

Scientists have created a compact spectral singlet lens that turns standard cameras into hyperspectral ones, reducing system size and complexity. This breakthrough could expand hyperspectral imaging into portable applications, with future improvements underway.

The information we gather shapes our understanding and perspectives of the world. For centuries, optics has sought to interpret the multidimensional data around us through the “toolbox” of light. In the 17th century, Sir Isaac Newton introduced the lens imaging formula and conducted his famous color spectrum experiment, laying foundational insights in the field.

Since then, lenses and spectrometers have been extensively studied as essential optical components for capturing information. Cascading these two components can allow us to acquire more information – both spatial and spectral data. However, such a configuration leads to tradeoffs among device footprint, spectral resolution, and imaging quality, impeding portability and miniaturization of hyperspectral cameras.

In a groundbreaking study published in Nature, scientists from JILA—a partnership between the National Institute of Standards and Technology and the University of Colorado Boulder—have managed to measure time dilation at an unprecedentedly small scale. This breakthrough involved detecting time differences between two clocks spaced only a millimeter apart, a distance as small as the width of a pencil tip. The experiment marks a major step forward in the precision of atomic clocks and sheds new light on the effects of gravity on time as outlined in Albert Einstein’s theory of general relativity.

Clocks that Measure the Effects of Gravity at the Millimeter Scale

Time dilation, a phenomenon where time moves more slowly in strong gravitational fields or at high speeds, was first predicted by Einstein’s relativity theory. JILA researchers, led by physicist Jun Ye, used highly precise atomic clocks in this experiment to measure these differences in gravitational time dilation over millimeter distances. By tracking frequency shifts among a sample of 100,000 ultra-cold strontium atoms held in a lattice, the team achieved a remarkable level of control, detecting how the gravitational pull from Earth slightly altered the passage of time over even this small distance.

Researchers have created a composite image showing dark matter’s role in linking galaxies, using data from 23,000 galaxy pairs located 4.5 billion light-years away. This discovery, through weak gravitational lensing, offers direct evidence of the dark matter web predicted for decades, moving from theoretical assumptions to measurable proof. The finding helps confirm dark matter’s critical role in keeping galaxies intact, at a time when some scientists are questioning its existence. Though still largely invisible, this breakthrough brings us closer to truly understanding the unseen forces binding the universe together.

The idea of dark matter originated out of sheer necessity. Given the amount of matter we can observe, the universe shouldn’t be able to exist and function the way it does—this visible matter simply can’t produce the gravitational forces required to hold galaxies together. Dark matter offers scientists a solution to this problem. They suggest the universe must contain a type of matter that we are unable to detect, one that doesn’t absorb, reflect, or emit light—hence, a truly “dark” form of matter.

To maintain the accuracy of our scientific models, dark matter would need to make up more than a quarter of the universe’s total matter. However, what exactly constitutes dark matter remains a mystery, and attempting to find evidence for something invisible is a difficult endeavor. Until now, scientists have primarily relied on observing its gravitational influence as indirect proof of dark matter’s existence. But researchers from the University of Waterloo in Ontario, Canada, have gone a step further—they’ve produced a composite image that confirms galaxies are linked by dark matter.

UCLAs new unidirectional imaging technology enables image formation in a single direction, preventing image capture in the reverse direction.

This novel technology, which operates effectively under partially coherent light, offers significant advancements in optical communication and visual information processing by providing selective, high-quality imaging.

Unidirectional Imaging

In space exploration, long-distance optical links now enable the transmission of images, videos, and data from space probes to Earth using light.

However, for these signals to travel the entire distance undisturbed, hypersensitive receivers and noise-free amplifiers are essential. Researchers at Chalmers University of Technology in Sweden have now developed a system featuring a silent amplifier and an ultra-sensitive receiver, opening up possibilities for faster and more reliable space communication.

Space communication systems are increasingly relying on optical laser beams instead of traditional radio waves, as light experiences less signal loss over vast distances. However, even light-based signals weaken as they travel, meaning that optical systems need highly sensitive receivers to detect these faint signals by the time they reach Earth. Researchers at Chalmers have developed an innovative approach to optical space communication that could unlock new opportunities—and discoveries—in space.

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.