Home Technology A 400-nm-diameter LED promises a breakthrough in photonics

A 400-nm-diameter LED promises a breakthrough in photonics

A 400-nm-diameter LED promises a breakthrough in photonics

A record-small LED will make it possible to create a holographic microscope to be built into smartphones (photo: CC0 Public Domain)

Uchthey developed the smallest forcespipe LED in the world – with a diameter of only 400 nanometers – and managed to build on its basis the smallest holographic microscope that can be integrated in smartphone.

The LED, created as part of the SMART (Singapore-MIT Alliance for Research and Technology) project, emits in the near-infrared range (wavelength 1100 nm). The emitting area is 0.14 µm² at a diameter of 400 nm, which is smaller than a wavelength, according to a publication of the development in the scientific journal Nature.

The appearance of such a component could mean a breakthrough in photonics, and in particular in the optical technologies used to transmit data, images, lighting and displays. A long-standing problem in this field has been the lack of sufficiently compact emitters, which required the use of external light sources with low energy efficiency, and photonic chips were difficult to scale.

The authors of the invention decided to test a record small LED, making a holographic microscope without lenses on its basis. Such microscopes are smaller and cheaper than conventional ones, as they do not require a complex and precise system of lenses – it is replaced by a light source that illuminates the examined sample, and the light falls into a CMOS matrix. As a result, a digital hologram is created, which after computer processing is converted into a readable image.

The last step is usually accompanied by certain difficulties: it is necessary to know precisely the value of the aperture, the wavelength of the light source and the distance from the sample to the sensor. An artificial intelligence algorithm helps overcome this difficulty.

It turns out that the microscope built with the new LED has a fairly high resolution – about 20 microns. In comparison, a human skin cell is 20 to 40 microns in size, and a leukocyte is 30 microns.

Scientists say such a microscope could be built into a smartphone to examine, for example, human tissue or plant seeds. A holographic microscope can also be used for biological imaging, to create various biosensors and implantable components.


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