Using a single lens that is about one-thousandth of an inch thick, researchers have created a camera that does not require focusing. The technology offers considerable benefits over traditional cameras such as the ones in most smartphones, which require multiple lenses to form high-quality, in-focus images.
These new flat lenses can drastically reduce the weight, complexity and cost of cameras and other imaging systems.
Such optics could enable thinner smartphone cameras, improved and smaller cameras for biomedical imaging such as endoscopy, and more compact cameras for automobiles.
In the journal Optica, the researchers describe their new flat lens and show that it can maintain focus for objects that are about 6 meters apart from each other. Flat lenses use nanostructures patterned on a flat surface rather than bulky glass or plastic to achieve the important optical properties that control the way light travels.
This new lens could have many interesting applications outside photography such as creating highly efficient illumination for LIDAR that is critical for many autonomous systems, including self-driving cars
Conventional cameras, whether used in smartphones or for microscopy, require focusing to ensure that the details of an object are sharp. If there are multiple objects at different distances from the camera, each object must be focused separately.
The new lens eliminates the need for focusing and allows any camera to keep all the objects in focus simultaneously.
Conventional cameras also use multiple lenses to keep different colors of light in focus simultaneously. Since the new design is very general, it can be used to create a single flat lens that focuses all colors of light, drastically simplifying cameras even further.
To focus light, traditional lenses transform parallel light waves into spherical waves that converge into a focal spot. In an important breakthrough, the researchers realized that waves with other shapes could produce a similar effect, vastly increasing the number of possible lens designs.
After choosing the best lens design for depth of focus, the researchers used nanofabrication techniques to make a prototype lens. Experiments confirmed that the new lens performed as expected and achieved a depth of focus several orders of magnitude larger than that of an equivalent conventional lens.
News Source: Eurekalert
