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Researchers have built an ultrafast camera capable of peering into an unseen world, which can even see light moving in slow motion.
Just over a year ago, Lihong Wang of Caltech revealed a camera capable of taking 10trn pictures per second. Now, he and his fellow researchers have published a study to Science Advances to describe a new camera that goes a step beyond by being able to snap 1trn photos per second of transparent objects.
This new technology, dubbed phase-sensitive compressed ultrafast photography (pCUP), is not only is capable of taking video of transparent objects, but also of ephemeral states such as light travelling in slow motion.
The new system combines the ultrafast photography from Wang’s earlier camera with an old technology referred to as phase-contrast microscopy. This was originally invented almost 100 years ago to allow better imaging of objects that are mostly transparent, such as cells, which are mostly water.
The technology works by taking advantage of the way that light waves slow down and speed up as they enter different materials. For example, a beam of light passing through a piece of glass will slow down upon entering the glass and speed up once it exits the other side.
A shockwave created by a laser striking water propagates in slow motion, as captured by a new ultrafast camera. Image: Caltech
What it saw
With the use of some optical tricks, it is possible to distinguish light that passed through the glass from light that did not. As a result, the glass, though transparent, becomes much easier to see.
“What we’ve done is to adapt standard phase-contrast microscopy so that it provides very fast imaging, which allows us to image ultrafast phenomena in transparent materials,” Wang said.
A pulse of laser light travels through a crystal in slow motion, as captured by the new ultrafast camera. Image: Caltech
The fast imaging part of the camera consists of something called lossless encoding compressed ultrafast technology (LLE-CUP). Unlike other ultrafast cameras that take a series of images in succession, the LLE-CUP system takes a single shot, capturing all the motion that occurs during that time.
In this new study, Wang and his fellow researchers demonstrated pCUP by imaging the spread of a shockwave through water and of a laser pulse travelling through a crystalline material. While still in early development, it may have a range of uses across academic fields.
“As signals travel through neurons, there is a minute dilation of nerve fibres that we hope to see. If we have a network of neurons, maybe we can see their communication in real time,” Wang said.
