In recent research published in Optics & Laser Technology and Infrared Physics & Technology, a research team led by Prof. Cheng Tingqing at the Hefei Institutes of Physical Science of the Chinese Academy of Sciences has introduced a novel low-thermal-effect gradient-doped crystal to tame thermal effects and improve the brightness of high-power end-pumped Nd: YAG lasers.
Traditional end-pumped solid-state lasers rely on uniformly doped crystals, which develop significant temperature gradients and thermal stresses under high pump power due to the axial absorption decay of pump power. These effects not only limit maximum pump power, but also degrade beam quality and conversion efficiency.
In this study, the researchers devised a numerical model for crystals whose neodymium concentration gradually increases along the rod, providing a theoretical basis for optimizing the concentration distribution and growth of novel gradient-doped crystals.
To improve photonic and electronic circuitry used in semiconductor chips and fiber optic systems, researchers at the McKelvey School of Engineering at Washington University in St. Louis tinkered with the rules of physics that govern the movement of light over time and space. They have introduced a new way to manipulate light transmission, opening possibilities for advanced optical devices.
Their method causes a “mirror-flip of the system,” said Lan Yang, the Edwin H. & Florence G. Skinner Professor of electrical and systems engineering and senior author of the research, now published in Science Advances.
Using parity-time (PT) symmetric photonic waveguides, they can manipulate the light waves to “reverse time” so the system behaves the same as before, Yang added.
Gravitational waves are constantly washing over Earth, but an astrophysicist aims to capture them in an entirely new way—by watching distant quasars appear to wiggle due to spacetime distortions.
Using data from the Gaia satellite, he’s searching for three-dimensional effects that previous techniques might have missed.
Exploring a new method to detect gravitational waves.
A scientist from Tokyo Metropolitan University has solved the longstanding problem of a “dissonance” in gravitational waves emitted by a black hole.
Using high precision computing and a new theoretical physics framework, it was discovered that it was caused by a resonance between a pair of distinctive “modes” i.e. different ways in which a black hole can “ring.” The phenomenon offers new insights into the nascent field of black hole spectroscopy.
The research is published in the journal Physical Review Letters.
We have long taken it for granted that gravity is one of the basic forces of nature – one of the invisible threads that keeps the universe stitched together. But suppose that this is not true. Suppose the law of gravity is simply an echo of something more fundamental: a byproduct of the universe operating under a computer-like code.
That is the premise of my latest research, published in the journal AIP Advances. It suggests that gravity is not a mysterious force that attracts objects towards one another, but the product of an informational law of nature that I call the second law of infodynamics.
It is a notion that seems like science fiction – but one that is based in physics and evidence that the universe appears to be operating suspiciously like a computer simulation.
Butterflies’ flight trajectories often appear random or chaotic, and compared with other hovering insects, their bodies follow seemingly mysterious, jagged, jerking motions.
These unique hovering patterns, however, can potentially provide critical design insights for developing micro-aerial vehicles (MAVs) with flapping wings. To help achieve these applications, researchers from Beihang University studied how butterflies use aerodynamic force generation to achieve hovering. They discuss their findings in Physics of Fluids.
“Hovering serves as an essential survival mechanism for critical behaviors, including flower visitation and predator evasion,” said author Yanlai Zhang. “Elucidating its aerodynamic mechanisms provides fundamental insights into the evolutionary adaptations of butterflies’ flight kinematics.”
Time crystals represent a new phase of matter proposed by Frank Wilczek, the Nobel laureate of Physics in 2004; they can break original time-translation symmetry and create new time oscillations spontaneously.
Recently, a joint research team from the National Time Service Center (NTSC) of the Chinese Academy of Sciences and Shanghai Jiao Tong University observed a time crystal in a spin maser system.
The results are published in Communications Physics.
Scientists have developed a dual-laser Brillouin optical correlation-domain reflectometry (BOCDR) system that uses two frequency-modulated lasers. By scanning the relative modulation phase between the pump and reference lasers, the setup measures strain and temperature all along an optical fiber. In a proof-of-concept test on a 13-meter silica fiber, the team recorded Brillouin gain spectra (BGS) at only about 200 MHz—over 50 times lower than the usual 11 GHz band.
The research was published in the Journal of Physics: Photonics on April 25, 2025.
“The dual-laser approach makes BOCDR equipment simpler, more cost-effective, and easier to deploy, giving engineers a practical tool for long-term structural health monitoring, factory process control, and many other sensing tasks,” said senior author Associate Professor Yosuke Mizuno of Yokohama National University.
Our Universe is vast, ancient, and mysterious. It’s no surprise that in our quest to explore and explain it, many misconceptions have arisen.
The first 1,000 people to use the link will get a 1 month free trial of Skillshare https://skl.sh/isaacarthur05231 Join this channel to get access to perks: / @isaacarthursfia. Visit our Website: http://www.isaacarthur.net. Join Nebula: https://go.nebula.tv/isaacarthur. Support us on Patreon: / isaacarthur. Support us on Subscribestar: https://www.subscribestar.com/isaac-a… Group: / 1,583,992,725,237,264 Reddit: / isaacarthur Twitter: / isaac_a_arthur on Twitter and RT our future content. SFIA Discord Server: / discord Listen or Download the audio of this episode from Soundcloud: Episode’s Audio-only version: / misconceptions-about-space-time-the-universe Episode’s Narration-only version: / misconceptions-about-space-time-the-univer… ▬ Common Misconceptions ▬▬▬▬▬▬▬▬▬▬ 0:00 Intro 2:34 Space is Huge 3:58 Space has no gravity 6:29 Space is not Dark 7:57 Space is Cold 12:14 Space is Empty 14:49 Explosive Decompression 16:31 No Noise in Space 17:48 Black Holes Suck 18:51 You can’t escape a Black Hole 22:37 Nothing goes faster than light 24:23 The Edge of The Universe is 13 Billion Light Years Away 27:23 The Universe has no Edge 29:31The Universe has no Center 30:13 We aren’t the Center of the Universe 32:48 Earth Orbits the Sun 35:34 The Sun is a fiery Yellow Dwarf 38:29 Time on Spaceships runs very slow 40:17 The Universe ends with the last stars Credits: Misconceptions About Space, Time & The Universe Science & Futurism with Isaac Arthur Episode 394, May 11, 2023 Written, Produced & Narrated by Isaac Arthur Editors: Briana Brownell David McFarlane Graphics: Jeremy Jozwik Music Courtesy of Epidemic Sound http://epidemicsound.com/creator. Facebook Group: / 1583992725237264 Reddit: / isaacarthur. Twitter: / isaac_a_arthur on Twitter and RT our future content. SFIA Discord Server: / discord.
Listen or Download the audio of this episode from Soundcloud: Episode’s Audio-only version: / misconceptions-about-space-time-the-universe. Episode’s Narration-only version: / misconceptions-about-space-time-the-univer…
▬ Common Misconceptions ▬▬▬▬▬▬▬▬▬▬ 0:00 Intro. 2:34 Space is Huge. 3:58 Space has no gravity. 6:29 Space is not Dark. 7:57 Space is Cold. 12:14 Space is Empty. 14:49 Explosive Decompression. 16:31 No Noise in Space. 17:48 Black Holes Suck. 18:51 You can’t escape a Black Hole. 22:37 Nothing goes faster than light. 24:23 The Edge of The Universe is 13 Billion Light Years Away. 27:23 The Universe has no Edge. 29:31The Universe has no Center. 30:13 We aren’t the Center of the Universe. 32:48 Earth Orbits the Sun. 35:34 The Sun is a fiery Yellow Dwarf. 38:29 Time on Spaceships runs very slow. 40:17 The Universe ends with the last stars.
Credits: Misconceptions About Space, Time & The Universe. Science & Futurism with Isaac Arthur. Episode 394, May 11, 2023 Written, Produced & Narrated by Isaac Arthur.
