Kyle Schurman
Dec 27, 2011

MIT trillion frames per second laser imaging camera impacts medical and industrial tech

Although it might look more like a movie trick, MIT researchers have come up with a method of capturing the movement of a pulse of laser light through the air.


Recording 30 frames per second of video is a standard performance level for consumer-level cameras. While that works well for shooting home movies of Sally’s soccer game, it won’t work in a commercial or medical application. The MIT camera can capture images at a rate of 600 million frames per second, which is at least 100 times faster than any specialty cameras currently on the market.


With the additional speed, the new MIT laser light camera could have applications in the medical world, where the ability to record laser light as it passes through tissues in the body could reveal any problems.


Laser light doesn’t last long, only about 50,000 trillionths of a second. Such speed makes it extremely difficult to capture the light in a photograph, and, technically, the laser light camera doesn’t capture the actual laser light in motion. Instead, it captures the reflection of the laser light as it bounces off objects.


The laser light camera works a bit like digital cameras used by consumers. In a standard digital camera, the light from the subject enters the lens of the camera, passing through to the digital image sensor. A processor then converts the light to digital signals, which can be saved as a file. The computer can read the digital signals and recreate the image on the screen.


Because electronic systems can only react within about 500 trillionths of a second, they’re not really fast enough to capture laser light. MIT researchers created a system that can use a shutter speed of about 2 trillionths of a second, which is fast enough for capturing the laser pulses. The laser light camera actually converts the light from the subject into electrons, which is a faster process than using an image sensor. A more traditional digital camera then records the light from the electrons.


To work with that speed, the laser light camera captures the reflection of multiple pulses, and then compares them to each other to create an image. The system will not work unless the laser light reflections are repeatable.


As of now, the MIT researchers have only used the laser light camera in a laboratory setting. The entire unit is about the size of an entertainment center, and it’s not mobile. Eventually, the researchers are hoping to have the entire system, including the camera and the laser light, equal to about the size of a laptop computer. The laser light camera’s resolution at this point is about 300,000 pixels (500 by 600 pixels) in size.


The laser light camera could have quite a few possible uses, if and when it is commercialized. In a medical setting, technicians could receive images similar to an ultrasound, only much more precise. The laser light would move through human tissue, and the camera would record the light as it bounces off the tissues.


Another option would allow photo technicians to completely change the way they create photographs. Using post-processing techniques, technicians could monitor the way that light interacts with objects in a scene, and then change that light after the photograph is recorded. Because the laser light camera would slow down the light, it would be easier to comprehend the way it moves in a scene.


Physicists and chemists might be able to use the system to record extremely fast chemical reactions, giving them a better understanding of how those reactions occur.


The number of applications built around laser light continues to grow. Having a way to further refine and manipulate laser light by the way the light is captured could further expand the way researchers will use laser light in products and applications.