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An elegant modification doubles the range of low-noise ‘white lasers’ in a single fiber

Supercontinuum light sources—often called “white lasers” because they emit a broad, continuous rainbow of colors—are essential tools for everything from advanced medical imaging to environmental gas detection. However, researchers have historically faced a frustrating trade-off: A broad spectrum comes at the expense of high fluctuations, which has effectively limited their use.

Now, a research team at DTU Electro has found an elegant way to bypass this limitation.

In a newly published study in Optica, the team demonstrated how to double the usable wavelength range of an ultra-low-noise supercontinuum laser. Their system successfully spans from 0.86 to 2.90 micrometers, nearly doubling the spectral range previously achieved by comparable low-noise systems while maintaining an astonishingly stable noise level.

Researchers demonstrate first fully solution-processed solid-state polariton laser

Researchers have demonstrated a solid-state organic laser microcavity fabricated entirely by solution processing. The device operates in the strong light–matter coupling regime, where light and matter form hybrid states called polaritons. This makes the platform not only a new type of solution-processed laser but also a powerful way to study nonlinear polariton interactions. The paper is published in the journal Nature Communications.

Solid-state lasers are used in many modern technologies, from telecommunications and sensing to medical diagnostics and data storage. However, their fabrication often requires complex and energy-intensive manufacturing methods. This new work shows that organic laser devices can be made in a much simpler way by coating each layer from a liquid solution rather than depositing it in a vacuum.

“Our main result is that we can make a complete solid-state laser microcavity using only solution processing. This is important because it shows that simple and scalable fabrication can still produce the high optical quality needed for advanced laser physics,” says Associate Professor Konstantinos Daskalakis from the University of Turku in Finland.

Never-before-seen woven structure that forms naturally inside a crystal discovered

For the first time, scientists have observed a three-dimensional woven structure forming naturally inside a crystal, revealing a previously unknown way in which matter can organize itself.

Published in Light: Science & Applications, the study reports the observation of a three-dimensional woven fabric of interlaced nano-dipole ensembles that emerges spontaneously in a ferroelectric crystal as it cools through its phase transition. Unlike conventional ferroelectric crystals, in which ferroelectric domains consist of aligned electric dipoles, the dipoles in this material spontaneously weave over and under one another, creating an intricate three-dimensional network that resembles woven fabric—a type of organization never before observed in a solid crystal.

The researchers also found that they could change small parts of the woven network using a tightly focused green laser. The light locally untangles the woven pattern without affecting the rest of the crystal. Heating the crystal and cooling it again restores the woven structure, but with a new pattern.

New quantum microscopy trick quadruples microscope resolution

Three years after a team of Caltech scientists showed that pairs of entangled photons could double the resolution of a light microscope, the same lab has figured out a way to double down on that improvement. They have now achieved a fourfold resolution boost compared to a classical microscope, using a new optical design that sends one of the entangled photons through the microscope’s optics three times rather than just once.

The work, led by Lihong Wang, the Bren Professor of Medical Engineering and Electrical Engineering and the Andrew and Peggy Cherng Medical Engineering Leadership Chair at Caltech, builds on the lab’s 2023 demonstration of quantum microscopy by coincidence (QMC). The approach relies on one of those bizarre quantum-mechanical phenomena called entanglement, in which two particles are linked such that the state of one particle is intimately tied to the state of the other no matter how far apart they might be.

In QMC, entangled pairs of photons, called biphotons, are split so that one photon, called the signal photon, passes through the sample while its entangled partner, called the idler photon, travels a separate parallel path. In some ways, the pair behaves as a single particle that has twice the momentum of an individual photon.

Single-shot phase imaging technique can reconstruct transparent objects

A KAIST research team led by professor Mooseok Jang from the Department of Bio and Brain Engineering has developed a single-shot phase imaging technique that reconstructs a phase object—a transparent object such as glass, plastic film or a living cell, which produces almost no visible contrast under an ordinary camera but induces a subtle shift in light called a phase change—from a single measurement, even when the object is fully enclosed between two dynamic scattering layers.

The findings are published in the journal Optica.

Phase objects are difficult to see with conventional cameras because they show little brightness contrast with their surroundings. However, analyzing the minute phase shift can reveal an object’s morphology and optical thickness and can be used to determine its physical thickness or refractive index variation when the other quantity is known. For this reason, phase imaging is widely used to observe living cells without staining and to inspect transparent components in semiconductors and displays.

Brain Waves Once Dismissed As Noise May Help Build Our Reality

Your brain may rely on sweeping waves of electrical activity to turn what your eyes see into a clear picture of the world.

Known as neural traveling waves, these electrical patterns move through brain tissue rather than remaining fixed in one location. By changing how responsive different groups of neurons are at a given moment, they may influence your attention, perception, and behavior.

In a review published in Neuron, Salk Institute neuroscientists argue that these waves are not merely background activity. Instead, they may function as a computational engine that helps the visual cortex create an internal model of the surrounding world. Similar processes could also operate in other parts of the brain.

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