Technology

New Super-Fast Film Camera Captures the Movement of Light

super-fast-cameras

High-speed cameras that can capture 100 000 images per second have just become slow compared to new technology that can capture images at five trillion images per second.

The research was done at Lund University in Sweden and the new camera can capture events as short as 0.2 trillionths of a second, which is much faster than has previously been possible. This makes it possible for the new super-fast film camera to capture incredibly rapid processes in physics, chemistry, biomedicine and biology that have not yet been captured on film.

To demonstrate the technology, the research team have effectively filmed how light, which is essentially a collection of photons, travels a distance equivalent to the thickness of a sheet of paper. Although this process only takes a picosecond, on film the process has been slowed down by a trillion times.

The new super-fast film camera (Image Credit: Kennet Ruona)
The new super-fast film camera (Image Credit: Kennet Ruona)

Current high-speed cameras capture images in a sequence one at a time. The new technology is based on an innovative algorithm that captures several coded images in one picture instead. The images are then sorted into a video sequence afterwards.

The method involves exposing the subject, for example a chemical reaction, to light in the form of laser pulses. Each light pulse is then given a unique code and each pulse reflected from the object is merged into the single photograph. These are afterwards separated using an encryption key.

It is envisaged that the film camera will initially be used by scientists who want to gain a better understanding of many of the processes that occur in nature extremely rapidly. Many of these processes take place on a picosecond and femtosecond scale, which is unbelievably fast. By way of comparison, the number of femtoseconds in one second is significantly larger than the number of seconds in a person’s lifetime.

Elias Kristensson explained that although not all processes in nature are this fast, there are a number of extremely fast ones, for example, plasma flashes, explosions, brain activity in animals, turbulent combustion and chemical reactions. Such extremely short processes can now be filmed using the new technology. In the long term, the technology could also be used by industry and in other applications.

For the researchers, it is not important that they set a new speed record, but the greatest benefit of this technology is that they will now be able to film how a specific substance changes in a process.

Kristensson added that currently the only way to visualize such rapid events is to take still images of the process. An attempt must then be made to repeat identical experiments to provide numerous still images, which can be compiled into a movie afterwards. He noted that the problem with this approach is that it is highly unlikely that a process will be identical when the experiment is repeated.

Elias Kristensson and Andreas Ehn normally conduct research on combustion. This area is known to be complicated and difficult to study. The eventual purpose of this basic research is to produce next generation gas turbines, car engines and boilers that are more fuel-efficient and cleaner. Combustion is controlled by a number of ultra-fast processes occurring at the molecular level and these can now be captured on film.

The researchers will for example study the lifetime of quantum states in combustion environments and in biological tissue, the chemistry of plasma discharges, as well as how chemical reactions are initiated. There will be more film material available in the autumn.

The full study was published in the journal Light: Science & Applications.