Engineers create a flat lens that doesn't need focusing

One lens to rule them all: smartphones with multiple cameras and blurry photos could become a thing of the past as engineers create a flat lens that doesn’t need focusing

  • The lens is covered in tiny patterns and is only a thousandth of an inch thick
  • Its use would have the potential to reduce camera weight, complexity and costs
  • The tech could also find applications in biomedical imaging and remote sensing

Smartphones with multiple cameras and blurry photos could become a thing of the past as engineers have created a flat lens that doesn’t need focusing.

The technology — which uses a single lens covered in tiny patterns that is just one-thousandth of an inch thick — was developed by experts from the University of Utah.

Not only could the lens lead to better and more compact cameras, but it could also find applications in biomedical imaging and remote sensing.

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Smartphones with multiple cameras and blurry photos could become a thing of the past as engineers have created a flat lens that doesn’t need focusing, pictured

‘Our flat lenses can drastically reduce the weight, complexity and cost of cameras and other imaging systems, while increasing their functionality,’ said research team leader and engineer Rajesh Menon, of the University of Utah.

‘Such optics could enable thinner smartphone cameras, improved and smaller cameras for biomedical imaging such as endoscopy, and more compact cameras for automobiles.’

He hopes it will drastically reduce the complexity and cost of cameras — while increasing functionality.

The novel lens design offers considerable benefits for smartphones — which currently require multiple lenses to form high-quality, in-focus images — and can maintain focus for objects that are almost 20 feet (6 metres) apart.

The flat lens design uses nano-structures patterned on a level 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,’ said Dr Menon.

LIDAR (light detection and ranging) is a remote sensing technology that measures distances by shooting a laser at a target and analysing the light reflected back.

The researchers say that the design approach they used could be expanded to create optical components with any number of properties, such as extreme bandwidth, easier manufacturability or lower costs.

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, then each object must be focused separately.


The novel lens design offers considerable benefits for smartphones — which currently require multiple lenses to form high-quality, in-focus images — and can maintain focus for objects that are almost 20 feet (6 metres) apart

‘The new lens eliminates the need for focusing and allows any camera to keep all the objects in focus simultaneously,’ said Dr Menon. This could rid the world of blurry photos, pictured

‘The new lens eliminates the need for focusing and allows any camera to keep all the objects in focus simultaneously,’ said Dr Menon.

‘Conventional cameras also use multiple lenses to keep different colours of light in focus simultaneously.’

‘Since our design is very general, we can also use it to create a single flat lens that focuses all colours of light, drastically simplifying cameras even further.’

To focus light, traditional lenses transform parallel light waves into spherical waves that converge on a focal spot.

The researchers realised that waves with other shapes could produce a similar effect, vastly increasing the number of possible lens designs.

‘In stark contrast to what is taught in optics textbooks, our research has shown there is more than one way light transmission is affected by an ideal lens — a concept known as pupil function,’ said Dr Menon.

‘This opened essentially infinite possibilities for the lens pupil function, and we searched through these possibilities for one that achieved an extreme depth of focus.’

After coming up with the best lens design, the team used a technique called nano-fabrication to make their prototype.

Experiments showed that it performed as well as expected — achieving a depth of focus several orders of magnitude greater than that of an equivalent conventional lens.

The researchers demonstrated the new lens using infrared light and relatively low numerical aperture — a scale that characterises the range of angles over which the lens can accept or emit light.

They plan to extend the lens to larger numerical apertures and to use it with the full visible light spectrum.

Work to ensure the lenses could be mass manufactured is also needed before they could be commercialised.

‘This research is a good example of how abandoning traditional notions can enable devices previously considered impossible. It serves as a good reminder to question dictates from the past,’ said Dr Menon.

The full findings of the study were published in the journal Optica.

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