Traditional cameras cannot be truly flat due to their optics: lenses that require a certain shape and size in order to function. At the California Institute of Technology, engineers have developed a new camera design that replaces the lenses with an ultra-thin optical phased array (OPA). The OPA does digitally what lenses do using large curved pieces of glass: it manipulates incoming light to capture an image.
The OPA’s large array of light receivers can individually add finely controlled phase shifts to the light it receives, allowing the camera to look in different directions and control focus.
“Here, like most other things in life, timing is everything. With our new system, you can selectively look in a desired direction and at a very small part of the picture in front of you at any given time, by controlling the timing with femto-second—quadrillionth of a second—precision,” says Ali Hajimiri, Bren Professor of Electrical Engineering and Medical Engineering in the Division of Engineering and Applied Science at Caltech.
“We’ve created a single thin layer of integrated silicon photonics that emulates the lens and sensor of a digital camera, reducing the thickness and cost of digital cameras. It can mimic a regular lens, but can switch from a fish-eye to a telephoto lens instantaneously—with just a simple adjustment in the way the array receives light,” Hajimiri says.
This first 2D lensless camera, following up on a one-dimensional version they created last year, has an array composed of just 64 light receivers in an 8 by 8 grid. The resulting image has low resolution, but this system represents a proof of concept for a fundamental rethinking of camera technology. Next, the team will work on scaling up the camera by designing chips that enable much larger receivers with higher resolution and sensitivity.
To learn more about this ongoing project, click here.