Researchers from the University of Ottowa have developed a concept that reduces the size of lenses by a huge margin and effectively eliminates the size of modern optics if combined with metal. The team did not tackle the lens elements themselves, but instead the space between them.
Researchers explain that the last few centuries of optical work have relied on perfecting and combining lenses to better control optical performance. Against this background, relatively new nanotechnology has enabled the development of metal lenses that have the capacity to shrink optics to a great extent.
But not addressed in metal evolution is the requirement for spacing between optical elements. No matter how small a lens may get, it still depends on space to produce images. This space will always be an obstacle to miniaturization unless it is addressed directly.
As described in the summary of the research paper, the researchers sharply address the issue of space by presenting the concept and experimentally demonstrating an optical “space plate.”
“… an optic that effectively propagates light over a distance that can be significantly longer than the plate thickness. Such optics would diminish future imaging systems and open up the possibility of ultra-thin monolithic cameras. More broadly, a space plate can be used to miniaturize important devices that implicitly manipulate the spatial profile of light, such as solar concentrators, collimators for light sources, integrated optical components, and spectrometers. ”
The team led by Dr. Orad Reshef – a senior postdoctoral fellow in the Robert Boyd Group – and Dr. Jeff Lundeen – Canadian chair of quantum photonics research and associate professor at the Department of Physics at the University of Ottawa – spoke with Phys and explained that the team would address how light propagates between optical elements and tackle aspects of the process that lens elements can do nothing about.
In an interview, Dr. Reshef that light is scattered naturally as it moves, and any optical device currently in use depends on the scattering to work. As an example, he points to the large gap between the eyepiece and the objective lens of a telescope or camera lens: both rely on distance and spread out to function properly.
But this hole and other holes in a lens design take up a lot of space, and his team developed what they call a “space plate” that is capable of taking the same scattering of light and compressing it into a “counterpart” to the lens and let entire imaging systems become dramatically smaller as a result.
“We were considering what would happen if you manipulated light based on the angle rather than the location of a light beam,” said Dr. Lundeen to Phys. Lenses work via the position of the beam. Angle is a whole new domain, and no one had shown that it could be used to do anything particularly useful. We identified a useful program that compresses space. And then we showed that we could actually design and experimentally demonstrate plates that do just that. ”
Dr. Reshef says this development would theoretically allow lens manufacturers to shrink down all sorts of large devices that were previously thought impossible to miniaturize.
“To design it, we need to come up with a new set of rules that are incompatible with what is used in lens design. Nobody knows what they are, it’s like the Wild West, ”he says. “It is surprising that optical elements such as lenses have existed for a millennium, and their design rules have been well understood for over 400 years, and yet we are still discovering such basic new optical elements for imaging.”
The space plate can work together with metal metals to significantly reduce the size of the optics to the point where the lens in e.g. Graphics appear to align with a camera sensor.
The researchers say they are currently working on developing the next generation of technology to increase the compression factor and improve overall performance.
“We already have some designs to increase the compression factor from five to over 100 times and to increase the overall transmission. To continue with this, we need to come up with a completely new design paradigm, ”says Dr. Lundeen.
While metal lenses have threatened to completely remove the camera bump in modern smartphones, the room plate in combination with the technology of the metal has the potential to eliminate modern lenses quite. It is a potentially revolutionary development in optical science, and the full research report can be read here.