Molecular coating cleans up noisy quantum light

Quantum technologies require perfection: one photon at a time, each time, all with the same energy. Even tiny deviations in the quantity or energy of photons can disrupt devices, threatening the performance of quantum computers, which can ever make quantum Internet.

Although this level of accuracy is difficult to achieve, engineers of the North -West University have developed a new strategy that makes quantum light sources that distribute individual photons, more consistent, accurate and reliable.

In a new study, the team covered atomically a thin semiconductor (tungsten disetenide) using a leaf organic molecule called PTCDA. The coating was transformed by the behavior of a tungsten discrete – the transformation of noisy signals into pure bursts of single photons. Not only did the coating increase the spectral cleanliness of photons by 87%, but also shifted the color of photons with a controlled way and reduced the activation of photons – all without changing the main semiconductor properties.

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A simple, scalable method can pave the way for reliable, effective quantum technologies for safe communications and ultra-drug sensors.

“When there are defects, such as missing atoms, in tungsten dyslenide, the material can radiate separate photons,” said Mark North -Wall Mark S. Khersam, the corresponding author of the study. “But these points of single -photon radiation are elegantly sensitive to any pollutants from the atmosphere. Even oxygen in the air can interact with these As for the emitters And change their ability to produce the same single photons. Any variability of the number or energy of emitted photons limits the productivity of quantum technologies.

“Having added a very uniform molecular layer, we protect single -photon emitters from undesirable pollutants.”

Khersam is the chairman of the Department of Materials Science and Engineering, as well as a professor of material science and engineering Walter P. Murphy at the School of a Technical Engineer in the North -West. He is also the director of the Scientific and Engineering Center of Materials and a member of the Executive Committee of the Institute for Research and Construction Information.

Like a trading machine for particles, quantum light sources emit one – and only one – photon at a time. If the source radiates several photons at the same time or photons of various energies, the consequences can be serious. In quantum communications, for example, additional photons limit cybersecurity. In quantum sounding, photons of various energies can reduce accuracy.

Since these seemingly futuristic technologies are approaching reality, the researchers struggled to develop photon sources, which are bright and pure, each time giving one identical photon on demand.

In the new study by Hersam and his team focused on a two -dimensional semiconductor tungsten dyslenide, which may have atomic -scale defects that distinguish individual photons. Since the tungsten disette is atomic thin, its defects and emitters are directly on the surface, leaving them with the influence of undesirable interactions with atmospheric pollution. This susceptibility to variability from random atmospheric species limits the reliability of tungsten dyslenide for accurate operations necessary in quantum devices.

To overcome these problems, the Khersam team covered both sides of the tungsten distequet PTCDA (perilentetracarbon dianhydrid), an organic molecule, which is often found in pigments and dyes. The team besieged molecules in Vacuum camera One molecular layer at a time, which guaranteed that the coating remained uniform. The molecular coating protected the surface The tungsten plunged And his quantum radiating defects, without changing its main electronic structure.

“This is a molecular ideal coating that is a uniform environment for single-photon sites,” Khersam said. “In other words, the coating protects sensitive quantum emitters from damage by atmospheric pollution.”

Buying the material from environmental disorders, the coating significantly improved the spectral cleanliness of photons. The coating also led to the transition of photons to lower energy, which is beneficial in quantum communication devices. The result is a more controlled, reproducible and more high -quality single -photograph output, which is crucial for Quantum technologiesField

“While the coating really interacts with quantum radiation defects, it shifts the energy of the photon uniformly,” said Khersam. “In contrast, when you have a random pollutant interacting with a quantum emitter, it unpredictably changes energy. Diversity is the key to reproducibility in quantum devices. ”

Then the Hersam group plans to explore other semiconductor materials and explore additional molecular coatings for further control over the objects of single -photon radiation. The team also plans to use an electric current to control quantum emissions, which will facilitate a network of quantum computers in Like the InternetField

“The big idea is that we want to move from individual quantum computers to quantum networks and, ultimately, the quantum Internet,” Khersam said. “Quantum communication will occur using Single photonsThe field our technology will help to create single-photon sources that are stable, customizable and scalable-associated components to create this vision. ”