Twistable Hexagonal Boron Nitride Layers Enable Tunable Quantum Light Sources

University of Technology Sydney researchers, led by Dr. Angus Gale and supervised by Prof. Igor Aharonovich, demonstrated that repeatedly picking up, twisting, and restacking atomically thin layers of hexagonal boron nitride (hBN) can alter the colour and wavelength of embedded quantum emitters. The experiment produced a shift in emission described as “much larger than expected,” surpassing the limited manipulation typical of other platforms such as diamond or silicon carbide. The study was published in *Advanced Materials*.

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Quantum emitters are nanoscale light sources capable of emitting single photons, a key resource for quantum computing, secure communication, and ultra-sensitive sensing. While detection of these emitters is routine, precise control over their optical output has remained a bottleneck. Conventional solid-state hosts offer only modest tuning, prompting the search for alternative materials with adjustable properties.

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The team exploited hBN’s naturally layered structure, separating the material into thin sheets, rotating one layer relative to another, and then restacking the pair. By varying the twist angle, they observed a pronounced shift in the emitted light’s colour and wavelength. The magnitude of the shift exceeded typical expectations for solid-state quantum-emitter platforms, indicating that the twistable architecture provides a powerful lever for optical control.

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The ability to fine-tune quantum emitters could accelerate practical quantum computers, secure communication networks, and high-precision sensors. Researchers cite applications in healthcare, cybersecurity, and navigation such as improved GPS.

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Dr. Gale emphasized that the method offers a new tool to bring quantum technologies closer to real-world use, highlighting the unusually large emission shift achieved. Prof. Aharonovich noted that twisting layered materials can generate entirely new physical behaviours, positioning the approach as a pathway toward scalable quantum devices.

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• “You can measure these quantum emitters and see that they exist, but it's hard to make them work in practice. This gives us a lever to get closer to that – a step towards the realisation of quantum technologies,” — Dr. Angus Gale, Lead Author, University of Technology Sydney

Quantum Potential Turns Into Reality

• “With a block of cheese, you can’t really get to the flavour in the middle. But with slices, you can peel away layers, put them back together and change how they interact,” — Dr. Angus Gale, Lead Author, University of Technology Sydney

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• “The benefit is that we used this twistable platform to shift the emission by a very significant amount,” — Dr. Angus Gale, Lead Author, University of Technology Sydney

Quantum Potential Turns Into Reality

• “You can take two layers that don’t do much on their own, put them together at a specific angle, and suddenly you have a completely different system,” — Prof. Igor Aharonovich, Supervising Author, University of Technology Sydney

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The researchers suggest that the twistable hBN platform could eventually contribute to quantum computing, quantum communication, and quantum sensing technologies across fields such as healthcare, cybersecurity, and navigation.

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