Many of us are dealing with lenses every day, for example, lenses in glasses or magnifying glasses that correct vision are lenses. Lens (English: lens) is a device that aggregates or disperses light. It is usually made of a piece of glass, but also made of transparent materials such as resin or crystal.
Conventional optical lenses adjust the phase of incident light by changing the thickness of glass or the like to achieve focusing. Such a lens is bulky, bulky, and can only focus light on a limited number of wavelengths.
With the continuous development of optical technology, traditional optical lenses are difficult to meet requirements such as large-scale integration, device miniaturization, and diversified functions. To this end, scientists and technicians have developed metalens.
The super lens is a two-dimensional planar lens structure in which optical antennas with special electromagnetic characteristics are arranged in a certain way by manual methods, which can flexibly adjust the amplitude, phase, polarization and other parameters of incident light. It has important applications in imaging, holographic optics, and achromatic lenses. The super lens not only breaks through the electromagnetic properties of traditional optical lenses, its two-dimensional planar structure is easier to process and integrate, and provides solutions for the miniaturization and integration of optical lenses.
Now, scientists at the University of California have developed a new, record-setting, ultra-thin ultra-lens (ultrathin metalens), which uses a series of small, interconnected waveguides, similar to a fishnet, with record-breaking efficiency. The light is focused in the wavelength range from visible light to infrared.
So the lens is called "fishnet achromatic super lens", English: Fishnet-Achromatic-Metalens, abbreviation: FAM. This super lens is flat and compact, and can be made small enough to meet the needs of increasingly miniaturized. This technological development will lead to revolutionary advances in changing solar energy, virtual reality technology, medical imaging, optical information processing, and other applications that rely on optics.
Boubacar Kanté, associate professor and principal researcher in electrical engineering and computer science at the University of California, Berkeley, said: "We have overcome what is considered a basic obstacle." "In short, this is the thinnest in the world , The most efficient and widest flat lens."
Although many methods have been proposed to realize flat lenses in the past decade, this new type of super lens is the first to achieve a combination of multiple performances.
The team demonstrated that its fishnet achromatic super lens can capture 70% of the incident light in the range from 640 nanometers (red-orange light) to 1200 nanometers (infrared light). The light entering the fishnet achromatic super lens in such a wide wavelength range will be focused on a single point on the other side of the lens.
Kanter said: "These results make us very excited, because many applications need to deal with multiple wavelengths in the broad spectrum at the same time." "For example, this is the case in solar applications, we need to focus all colors of light to efficient On solar cells or solar concentrators."
Kanter said that a good step in the next step is to develop processes that can achieve mass production.
The latest research results paper was published in today's "Nature Communication" magazine.
Reference: Octave bandwidth photonic fishnet-achromatic-metalens, Nature Communications (2020). DOI: 10.1038/s41467-020-17015-9