Scientists at the University of California, Santa Barbara have made significant strides in engineering quantum defects for more efficient single-photon generation, paving the way for a robust quantum internet.
Just as the internet revolutionised communication, a quantum internet promises to revolutionise information processing and security. But for this to become reality, a crucial component is the ability to transmit quantum information over long distances, a feat best achieved with photons.
Photons, the fundamental particles of light, are remarkably stable and minimally affected by their environment. This makes them ideal carriers of quantum information, which relies on delicate entanglement states. While fibre-optic cables have long been optimised for low-loss photon transmission, this works best within a narrow range of wavelengths known as the "telecom wavelength band."
Historically, identifying quantum defects, which emit photons within this critical band, has been a challenge. Researchers have struggled to understand why the efficiency of single-photon emission decreases drastically as the emission wavelength moves from visible to infrared wavelengths, crucial for the telecom band.
The team at UC Santa Barbara, led by Professor Chris Van de Walle, addressed this challenge by developing theoretical models to explain the impact of atomic vibrations on the photon emission process. These models revealed that the vibrations within materials can drain energy from the emitters, reducing their efficiency.
The research, published in the journal *APL Photonics*, demonstrates the crucial role of atomic vibrations in determining the efficiency of single-photon generation. This understanding provides the key to engineering brighter and more efficient quantum emitters.
âChoosing the host material carefully, and conducting atomic-level engineering of the vibrational properties are two promising ways to overcome low efficiency,â explained Mark Turiansky, a lead researcher on the project.
Another approach involves coupling the emitters to a photonic cavity, an area where the team benefited from the expertise of Professor Galan Moody and his graduate student Kamyar Parto.
The research offers a significant step towards unlocking the potential of a quantum internet. By harnessing the power of quantum defects, researchers are closer than ever to creating efficient quantum emitters that can power the future of communication and information processing.
