Johannesburg, November 2025
Quantum Light Gets a High-Dimensional Upgrade, Promising Secure Communication and Faster Computing
Table of Contents
- Quantum Light Gets a High-Dimensional Upgrade, Promising Secure Communication and Faster Computing
- Beyond Bits: The Rise of Qudits
- Securing Communication, Speeding Up Computation
- Imaging, Sensing, and Materials Discovery
- Two Decades of Evolution
- A Turning Point for Quantum Technology
- A Global Effort, Rooted in Collaboration
Scientists are harnessing the power of structured light to transmit information in ways previously thought impossible, potentially revolutionizing fields from cryptography to materials science.
- Researchers are moving beyond traditional qubits to “qudits,” which can carry significantly more information.
- This advance boosts security in quantum communication by packing more data into each photon.
- Quantum structured light is also accelerating progress in imaging, sensing, and the simulation of complex materials.
- The field has seen dramatic progress in the last two decades, with the development of compact, on-chip sources of quantum light.
A new review published in Nature Photonics details how an international research team, including scientists from the UAB, is reshaping information transmission, measurement, and processing through the manipulation of light. The key? Merging quantum information science with carefully engineered patterns of light in space and time, resulting in photons capable of carrying far more information than ever before. Quantum structured light offers a pathway to more secure and efficient data transfer.
Beyond Bits: The Rise of Qudits
The research centers on controlling multiple properties of light simultaneously – including polarization, spatial modes, and frequency – to create what are known as high-dimensional quantum states. This is a significant departure from standard qubits, the fundamental units of quantum information, which exist in a two-dimensional state (a superposition of two possibilities). Instead, researchers are utilizing “qudits,” which possess more than two dimensions, dramatically expanding the capabilities of quantum systems and opening new avenues for scientific and technological breakthroughs.
Securing Communication, Speeding Up Computation
The implications are far-reaching. In quantum communication, these high-dimensional photons enhance security by increasing the amount of information encoded in each particle of light. They also enable multiple communication channels to operate concurrently, improving resilience to errors and background noise. For quantum computing, structured light promises to simplify circuit designs, accelerate processing speeds, and facilitate the creation of complex quantum states essential for advanced simulations.
Imaging, Sensing, and Materials Discovery
The benefits extend beyond communication and computation. Quantum structured light is also driving advancements in imaging and measurement techniques. Researchers highlight the recent development of the holographic quantum microscope, which allows for the imaging of delicate biological samples with unprecedented detail, alongside the creation of highly sensitive sensors that leverage quantum correlations. Furthermore, structured light can simulate complex quantum systems, aiding scientists in modeling molecular interactions and potentially accelerating the discovery of novel materials.
Two Decades of Evolution
According to Professor Andrew Forbes, from the University of the Witwatersrand, at Johannesburg, the field has undergone a remarkable transformation over the past 20 years. “The tailoring of quantum states, where quantum light is engineered for a particular purpose, has gathered pace of late, finally starting to show its full potential. Twenty years ago the toolkit for this was virtually empty. Today we have on-chip sources of quantum structured light that are compact and efficient, able to create and control quantum states.”
Despite this progress, challenges remain. “Although we have made amazing progress, there are still challenging issues,” Forbes added. “The distance reach with structured light, both classical and quantum, remains very low, but this is also an opportunity, stimulating the search for more abstract degrees of freedom to exploit.”
A Turning Point for Quantum Technology
Researcher Adam Vallés, from the Optics Group of the UAB Department of Physics, believes the field has reached a pivotal moment. “We are at a turning point: quantum structured light is no longer just a scientific curiosity, but a tool with real potential to transform communication, computing and image processing.” Vallés emphasized the UAB’s significant contributions to this progress, citing advancements such as the stimulated teleportation of quantum information encoded in high dimensions, the design of laser cavities for generating complex states, and the development of robust quantum key distribution systems capable of overcoming communication obstacles.
A Global Effort, Rooted in Collaboration
The review article, featured on the cover of the November 2025 issue of Nature Photonics, is the result of a long-standing partnership between Vallés and the structured light research group led by Forbes at the Faculty of Physics of the University of the Witwatersrand in Johannesburg, South Africa. The work received support from the Catalonia Quantum Academy (CQA), a collaborative initiative coordinated by the Institut de Ciències Fotòniques (ICFO) and promoted by the Government of Catalonia, dedicated to strengthening education and talent development in quantum sciences and technologies throughout the region.
