World’s fastest single-shot camera confirms how flames form soot Premium

The innovation, led among others by Dr. Yogeshwar Nath Mishra, can capture 12.5 billion frames per second.

Scientists from Germany and the U.S. have built the world’s fastest single-shot laser camera – 1,000x faster than its predecessors at capturing extremely short-lived events. They used the camera to provide the most precise view yet of how a hydrocarbon flame produces soot, which can teach us about how this important climate pollutant is produced in kitchen stoves, car engines, and wildfires.

The device’s technique is called laser-sheet compressed ultrafast photography (LS-CUP). It “can resolve a plane of a three-dimensional object like a flame or spray or any turbid media and can “resolve physical or chemical processes” in space and time, Yogeshwar Nath Mishra, a coauthor of the work’s paper, published in Light: Science & Applications, told The Hindu by email.

Dr. Mishra is a researcher with the University of Gothenburg, Sweden, the NASA Jet Propulsion Laboratory in California, and at the Caltech Optical Imaging Laboratory. He hails from Azamgarh.

The researchers’ LS-CUP device can capture images at 12.5 billion frames per second (fps). To compare, the standard frame rate for films and TV shows is 24 fps. They used it to capture the “emission, soot temperature, primary nanoparticle size, soot aggregate size, and the number of monomers” of polycyclic aromatic hydrocarbons – molecules that go on to form soot.

They wrote in their paper that they found “strong experimental evidence in support of the theory and modelling of soot inception and growth mechanism in flames”. Such evidence is required to validate models used to predict how much soot forms in different industrial processes. Soot changes rainfall patterns and melts glaciers faster.

Their device can also be used to photograph shockwaves in nuclear reactors, combustion of fine sprays, and an enigmatic process called sonoluminescence (sometimes, when excited by sound, bubbles in a liquid implode and release light at a temperature of ~10,000 K), all of which involve processes that happen in a few nanoseconds.

LS-CUP has three components: “We have combined laser sheet imaging with compressed sensing on a standard streak camera system,” in Dr. Mishra’s words.