Japanese researchers build trillion-frame-per-second camera
01 May 2015
Researchers from Japan have developed a new high-speed camera that is three orders of magnitude faster than conventional high-speed cameras.
Called STAMP (Sequentially Timed All-optical Mapping Photography), the new camera technology holds promise for studying a diverse range of previously unexplored complex ultra-fast phenomena, according to Keiichi Nakagawa, a research fellow at the University of Tokyo, who worked to develop the camera with colleagues from various Japanese research institutions.
Conventional high-speed cameras are limited by the processing speed of their mechanical and electrical components. STAMP overcomes these limitations by using only fast, optical components.
Another optical imaging technique, called the pump-probe method, can create movies with an even higher frame rate than STAMP, but can only capture one frame at a time, limiting its use to processes that are exactly reproducible.
"Many physical and biological phenomena are difficult to reproduce," says Nakagawa. "This inspired me to work on an ultra-fast camera that could take multiple frames in a single shot."
STAMP relies on a property of light called dispersion. It splits an ultrashort pulse of light into a barrage of different coloured flashes that hit the imaged object in rapid-fire succession. Each separate colour flash can then be analysed to string together a moving picture of what the object looked like over the time it took the dispersed light pulse to travel through the device.
In the first iteration of STAMP, the number of frames that the camera could take in a single shot was limited to six. Currently, the team is constructing an improved STAMP system that can acquire 25 sequential images. Nakagawa believes the number of frames could eventually be increased to 100 with current technology.
Nakagawa cautions that because STAMP operates on the assumption that all the differently coloured daughter pulses interact with the imaged object in the same way, the camera should not be used to image samples whose optical properties change over the range of wavelengths STAMP uses.
But given STAMP's limitations, the technology has enormous potential, according to Nakagawa. His team has already used it with image electronic motion and lattice vibrations in a crystal of lithium niobate and to observe how a laser focused onto a glass plate creates a hot, rapidly expanding plume of plasma.
Nakagawa notes that the camera could be used to explore a wide range of ultra-fast phenomena for the first time, including the laser ignition of fusion, the phase transition of materials, and the dynamics of a Coulomb explosion, an event in which intense electromagnetic fields (for example from a narrow laser beam) can force a small amount of solid material to explode into a hot plasma of ionized atomic particles.