high speed imaging spectroscopy

A gas target is like a funnel: the steeper its walls, the stronger the flow. But in this funnel, it is not water that flows, but ultraviolet light, born when a powerful laser pulse passes through a cloud of argon. The efficiency of this conversion is usually minuscule, about 0.001%: out of a thousand laser photons, only one turns into useful ultraviolet.

A laser beam strikes a thin target hidden inside layers of another material. Within billionths of a second, the material is compressed to a density of 25 grams per cubic centimeter, as if a piece of lead became more than twice as heavy without moving an inch.

Starlight passing through the atmosphere and telescope optics shimmers like sunlight dancing on water. Hidden in that ripple are planets — faint sparks next to a blinding glare. To see them, you have to freeze the ripple: make the light as smooth as glass.

A protein in a cell is not a frozen sculpture but a restless mechanism. Its parts are constantly vibrating, and these movements determine how it grabs molecules, transmits signals, or builds the cellular scaffold. But filming the life of a single protein was hampered by two nuisances at once. First, the movements last millionths of a second — ordinary cameras simply cannot catch them.

A single-pixel camera works like an artist creating a picture through a stencil with many holes. In each frame, only a portion of the light, modulated by a mask, a spatial light modulator, reaches the single sensor, and then the computer reconstructs the full image by assembling this mosaic with computational algorithms.

A protein in a cell is not a frozen sculpture. It is constantly in motion: bending, breathing, jittering. This motion, its dynamics, determines how the protein works. But peering directly into the dance is hard, and computer simulations often demand enormous computing power. A new approach, named DynaMode, views protein motion as a musical piece.

A smartphone camera captures everything indiscriminately, but the eye immediately picks out what matters. The retina doesn't just pass the image to the brain: it highlights contours on the spot, suppresses noise, and adjusts to brightness.

The scene is lit by spotlights, but the most interesting action happens in the shadows — where molecules invisible to the eye are hiding. The new camera picks up the heat of these "invisible" objects and turns it into ordinary light.

A drop of water in your palm holds roughly $$10^{21}$$ molecules, each made of three atoms surrounded by a swarm of electrons. To understand how matter behaves, physicists solve equations for these electrons. The trouble is that the number of equations grows like an avalanche: for N electrons, you need to store $$N^2$$ numbers.

An X-ray machine with gratings takes not one but three pictures at once: a regular image, a map of beam deflections invisible to the eye, and an image of tiny structures that scatter light. Together, they help spot, for example, emphysema or pulmonary fibrosis. But there's a catch: to separate these three layers, you need a clever mathematical trick.

A conventional lidar is like an artist who paints a landscape but sees only gray shadows. It measures distances to each point accurately, but can't tell whether it's looking at rock, wood, or plastic. To learn the composition, you need a spectrometer — a separate device that works slowly and can't keep up with a fast scanner. The new system takes a different approach.

An X-ray beam is a stream of tiny packets of energy, photons. Ordinary detectors count them but don't distinguish shades: two photons with close energies look the same to them. The new device works like a sensitive thermometer: it catches each photon and measures how much it warms a thin film. From the warming, you can tell exactly how much energy the photon brought.

A laser strikes the crystal, and it responds with flashes of light, like a bell ringing after a blow. But if the bell is warm, its sound wavers and fades. Same here: the crystal's atoms constantly jitter from heat, and this jitter disrupts the electrons' smooth flight, making the light dim and blurry.

Any cook knows: whether dough sticks to a pan depends on what happens at the interface between two media. For molten metals, that interface long remained invisible — temperatures above 200 °C made it impossible to resolve individual atoms.

A film as thin as a spider's web, made of five metals, took the hit from a laser. Inside, the pressure soared to 55 gigapascals — imagine a hundred elephants balanced on your thumbnail. The alloy withstood it, compressing for a fraction of a nanosecond without breaking. One gigapascal is a thousand megapascals.

A regular camera captures the world as a series of frames: twenty-four, sixty, or even a hundred images per second. That's enough for filming a falling drop, but inside a living cell, events unfold a thousand times faster. Protein molecules carry cargo, membranes bubble, ions slip through channels — all in fractions of a millisecond.

A laser melts metal powder layer by layer, and inside the boiling pool, vapor bubbles appear and collapse within milliseconds. Seeing this kitchen in action was previously impossible: the X-ray tomograph that takes 3D images is too slow. The sample has to rotate, and by the time it does, the melt has already changed a hundred times.

Two laser beams, like two pencils, draw an invisible scale on the wall. One tip moves slightly faster than the other, and by the way their strokes alternately coincide and diverge, you can calculate the distance to the wall with an accuracy down to the thickness of a spider's thread. In the new work, physicists made these two beams work continuously, without pauses.

An X-ray image usually brings to mind a bulky machine in a hospital. But such a picture can be taken by a device the size of a palm, assembled from hobbyist electronics. The authors took a Raspberry Pi mini-computer, a 12.3-megapixel camera, and a screen that glows under X-rays.

Light passing through a lens bends slightly. For an optical computer, this is like a warped mirror for an artist: the image is there, but the details blur. An Ising machine using light beams tackles problems like packing luggage or planning a courier's route.

The laser in question is not a thin beam but a whole running track for light. Inside the optical fiber, two ultrashort pulses race: one clockwise, the other counterclockwise. Each pulse is a single flash lasting billionths of a second.

An X-ray machine at the dentist's office takes a single flat image of a tooth. But if you need to see the insides of a microchip from all sides, you have to take the sample to a synchrotron — an accelerator the size of a football field.

In the dark, a tiny spark flashes. A gamma ray born inside a patient's body strikes a crystal and knocks out a shower of light. The detector's job is to figure out exactly where that happened. The more precise the answer, the sharper the image on the tomograph screen. The new detector resembles a honeycomb, but not a flat one — the cells narrow toward the bottom.

A conventional thermal camera is like a thermometer that slowly heats up and cools down. It shows where heat is well, but it can't keep up with fast motion. The new sensor works differently: it counts individual quanta of heat, like a droplet counter during rain.

A typical 3D printer squeezes out plastic like a pastry chef piping cream from a bag. Here, instead of plastic, it's light. A laser beam draws in liquid resin, making it solidify at precise points. This creates parts too small to see without a microscope. Until now, such printers were slow: the beam crawled across the surface like a pen on paper.

Cells breathe. They need oxygen, and they take it from the blood flowing through the tiniest vessels. If blood flow is weak or oxygen is scarce, cells start to suffocate. Doctors need to see this as early as possible. But how do you look inside living tissue without cutting it open? The new device does it in two ways at once.

Vanadium oxide is a material that can act as an insulator, not conducting electricity, or as a conductor, like a metal. The switch takes trillionths of a second, and that's what makes it a candidate for ultrafast electronic devices. But exactly how it happens has long been a mystery.

Some superluminous supernovae show a bright oxygen imprint in their light and expand rapidly, while others do not. It seemed like different phenomena. But supernova PTF12dam broke the rules: as its brightness grew, its oxygen signature changed, shifting from one type to another.

A fridge magnet holds on thanks to tiny internal arrows: each one like a miniature compass. If you hit the metal with an ultrashort flash of light, these arrows start to jitter chaotically, and magnetism melts away in a millionth of a billionth of a second. Previously, such 'melting' was too fast to observe.

Shine a flashlight through rough glass, and the wall lights up with a speckled pattern of bright and dark dots. Once dismissed as useless noise, this pattern now serves as the key to reconstructing 3D images. In the new system, light from an object passes through a specially designed plate with known irregularities.