American researchers have managed to develop a camera based on superconducting nanowires, capable of detecting individual photons with a definition 400 times greater than that currently available. Their method is scalable and should make it possible to create sensors with even higher definition, and sensitive enough to see inside the brain.
Single photon detectors are capable of capturing photos individual, but they are limited to a few pixels and often quite large. However, a new camera, much more powerful and compact, could pave the way for many advances in different fields. Researchers from the National Institute for Standards and Technology (Nist) in the United States have succeeded in creating a new photon camera with a definition 400 times greater than the best currently available.
The device is a nanowire-based single photon detector super conductors(SNSPD). This camera can detect different light frequencies, from ultra violet at the infrared, passing through the spectrum visible, and capture images in a matter of pico seconds. Each pixel is made of a nanowire cooled to a temperature of 0.8 degrees Kelvin(-272.35°C) in order to be superconductive . The nanowire is energized in such a way that it loses its super conductivity when hit by a photon.
A matrix of heating elements to collect the data
To individually connect a million cooled nanowires in this way would be impossible. The researchers then tried to integrate a data bus connected to all the detectors on a row or column, thus simplifying the wiring and limiting the number of wires that connect the device collecting the data to the detectors placed in a cryostat. However, this system has created manyinterference.
The researchers therefore had the idea of integrating heating elements which are triggered when the nanowire loses its superconductivity. They heat the data bus which is also superconductive . The bus loses its superconductivity at this point, which can be detected and transmitted. This system makes it possible to isolate the data bus from the detectors and avoid any interference.
A system sensitive enough to see inside the brain
The researchers thus succeeded in constructing a matrix of detectors of 800 rows by 500 columns, for a total definition of 400,000 pixels. Thanks to their data bus and heating element system, the system is scalable and should allow the creation of large-format superconducting cameras capable of detecting a wide range of the electromagnetic spectrum.
This type of high-precision camera could enable advances in the fields of quantum computing, space exploration and communications. However, the most promising area is brain imaging , offering a non-intrusive system using thelight. The camera would be able to detect the little light that passes through the head, making it possible to obtain images of the whole brain in real time.