Single-photon source paves the way for practical quantum encryption at room temperature

(ScienceDaily.com) “Science News” from Science Daily has provided a synopsis of recent research that is an important step toward practical applications of quantum technology, such as highly secure communication based on quantum key distribution. Inside Quantum Technology summarizes here:

Researchers from the University of Technology Sydney have developed a new high-purity single-photon source that can operate at room temperature. The source is an important step toward practical applications of quantum technology, such as highly secure communication based on quantum key distribution (QKD).
QKD systems require robust and bright sources that emit light as a string of single photons. However, most of today’s single-photon sources don’t perform well unless operated at cryogenic temperatures hundreds of degrees below zero, which limits their practicality.
Zeng and colleagues set out to create a better solution by using a solid immersion lens to focus the photons coming from the single-photon emitter, allowing more photons to be detected. These lenses are commercially available and easy to fabricate.
“We developed an on-demand way to generate photons with high purity in a scalable and portable system that operates at room temperature,” said Helen Zeng, a member of the research team from the University of Technology Sydney in Australia. “Our single-photon source could advance the development of practical QKD systems and can be integrated into a variety of real-world quantum photonic applications.”
In the Optica Publishing Group journal Optics Letters, Zeng and colleagues from Australia’s University of New South Wales and Macquarie University described their new single-photon source and show that it can produce over ten million single photons per second at room temperature. They also incorporated the single-photon source into a fully portable device that can perform QKD.
The new single-photon source uniquely combines a 2D material called hexagonal boron nitride with an optical component known as a hemispherical solid immersion lens, which increases the source’s efficiency by a factor of six.
Now that the researchers have established proof that their portable device can perform complex quantum cryptography, they plan to perform further testing of its robustness, stability, and efficiency during encryption. They also plan to use the new source to perform QKD in real-world conditions, rather than inside the lab. “We are now ready to transform these scientific advances in quantum 2D materials into technology ready products,” said Igor Aharonovich, who led the project.