Reviewed by Lexie CornerMay 23 2024
TMOS researchers created and demonstrated an innovative device for measuring photon pairs using an ultra-thin metasurface. The findings were published in the journal Optica.
An increasing number of upcoming quantum applications rely on optical technology. Photons transport information at the speed of light over large distances, making them ideal candidates for rapid and secure communications and quantum computing. Many of these applications demand identical (indistinguishable) photons. When photons are not identical, mistakes in data occur, making quantum technology less dependable.
Quantum photon sources are periodically taken offline to be examined and modified with an interferometer. This necessitates comparing photons numerous times using different configurations, which takes time and necessitates a large device capable of accommodating the various physical arrangements.
Real-time study of photon indistinguishability, which could be performed within a device while it is in operation, has the potential to increase quantum technology accuracy.
The novel device, developed by TMOS researchers at the Australian National University, performs all essential measurements in a single pass.
This metasurface-enabled multiport interferometer can determine if a photon pair’s properties are identical in a single shot. It doesn’t need multiple measurements using phase or time delays because the multiport structure allows the device to run measurements concurrently. This enables real-time and accurate characterization.
Jihua Zhang, Study Co-Lead Author and Researchers, Australian National University
One significant benefit is that this multiport interferometer is single-element, which not only minimizes size but also makes it ultrastable when compared to earlier multiport interferometers in a free-space optical configuration.
The application of meta-optics reduces the device's size, weight, and power while lowering production costs. Flat optics, also known as meta-optics, is critical to miniaturizing optical systems, eventually leading to the miniaturization of everyday devices.
We created a static, dielectric metasurface grating without any reconfigurable elements. The grating was designed using multi-factor topology optimization, which is essentially adjusting the surface pattern so that it interacts with light in a specific way. After successful simulations, fabrication, and a one-off calibration, we were able to successfully characterize the similarity of the photons’ spatial mode, polarization, and spectra.
Jinyong Ma, Study Co-Lead Author and Postdoctoral Researcher, Australian National University
Chief Investigator Andrey Sukhorukov, who leads the research from the Australian National University, added, “The success of our experimental trials suggests that the work could be further developed to also measure the indistinguishability of other photon properties, such as orbital angular momentum. It could underpin ultracompact and power-efficient optical elements that would be especially suited for portable and satellite-based free space quantum photonic technologies.”
Journal Reference:
Zhang, J., et al. (2024) Single-shot characterization of photon indistinguishability with dielectric metasurfaces. Optica. doi:10.1364/OPTICA.516064.