Researchers have created the world’s smallest and most sensitive microwave detector, beating the previous record by fourteen fold, an advance which may help in making ultra-sensitive cameras and accessories for emerging quantum computers.
The detector, which is smaller than a human blood cell, has a simple design of superconducting aluminum and a single golden nanowire.
“For us size matters. The smaller the better. With smaller detectors, we get more signal and cheaper price in mass production,” said Mikko Mottonen from Aalto University in Finland.
This design guarantees both efficient absorption of incoming photons and very sensitive readout. The whole detector is smaller than a single human blood cell, the researchers said.
The new detector works at a hundredth of a degree above absolute zero temperature. Thermal disturbances at such low temperatures are so weak that researchers could detect energy packets of only a single zeptojoule, they said.
That is the energy needed to lift a red blood cell by just a single nanometre, they added.
The device uses an external energy source to amplify its readings, allowing scientists to recognize the most minuscule of thermal energy changes.
Microwaves are currently used in mobile phone communications and satellite televisions, thanks to their ability to pass through walls.
More sensitive microwave detectors may lead to great improvements of the present communication systems and measurement techniques, researchers said.
Besides communication systems, the new detector could be used as a measurement device in the emerging superconducting quantum computer, they said.
“Existing superconducting technology can produce single microwave photons,” said Joonas Govenius from Aalto University.
“However, detection of such travelling photons efficiently is a major outstanding challenge. Our results provide a leap towards solving this problem using thermal detection,” Govenius said.
A microwave detector may also be useful for thermodynamics of small systems, researchers said.
“Quantum thermodynamics may give yet another boost to technology since it deals with individual energy levels or particles, and is in this sense more precise than classical thermodynamics,” said Mottonen.
The findings were published in the journal Physical Review Letters.