May 6, 2024

A Quantum Breakthrough: How a Multifunctional Metalens is Transforming Photonics

By Changchun Institute of Optics, Fine Mechanics And Physics, CAS
August 12, 2023

Artistic illustration of a multifunctional metalens used for approximate shaping of quantum emission from 2D hexagonal boron nitride. Credit: Chi Li, Jaehyuck Jang, Trevon Badloe, Tieshan Yang, Joohoon Kim, Jaekyung Kim, Minh Nguyen, Stefan A. Maier, Junsuk Rho, Haoran Ren, Igor Aharonovich
Researchers have actually developed a multifunctional metalens efficient in structuring quantum emissions from single photon emitters. This innovation enables manipulation of quantum emissions and assures brand-new advances in quantum innovation, consisting of potential influence on cryptography and info security.
Quantum emission is critical to recognizing photonic quantum technologies. Solid-state single photon emitters (SPEs), such as hexagonal boron nitride (hBN) flaws, run at room temperature level. They are extremely preferable due to their effectiveness and brightness. The standard way to gather photons from SPEs depends on a high numerical aperture (NA) objective lens or micro-structured antennas. While photon collection efficiency can be high, these tools can not manipulate quantum emissions. Several bulky optical aspects, such as polarizers and stage plates, are needed to attain any preferred structuring of the given off quantum light.
Development of Multifunctional Metalens
In a new paper published recently in the journal eLight, an international group of researchers led by Drs. Chi Li and Haoran Ren from Monash University have established a brand-new multifunctional metalens for structuring quantum emissions from SPEs. The capability to arbitrarily transform an optical beam in different spatial forms is essential for quantum lights.

Changing Photonic Design with Metasurfaces
Just recently, the direct combination of nanoscale emitters into nanostructured resonators and metasurfaces has been created to gather and demonstrate fundamental customizing of the SPEs emission. These initial presentations made up the necessity for flat optics to advance the manipulation of quantum emission.
Engineering and Demonstration of New Metalens
The research team has addressed this problem by designing and crafting a multifunctional metalens. The new metalens was fabricated by Korean physicists Drs. Jaehyuck Jang and Trevon Badloe and Professor Junsuk Rho at Pohang University of Science and Technology. It can simultaneously tailor the directionality, polarisation, and orbital angular momentum (OAM) degrees of freedom. They utilized the metalens to demonstrate a multidimensional structuring of quantum emission from SPEs in hBN, running at space temperature.
Advancement in Shaping Quantum Emission
The team showed arbitrary shaping of the directionality of quantum emission. They likewise showed that different helical wavefronts might be added onto the metalens profile, leading to the generation of distinctive OAM modes in orthogonal polarisations of SPEs. The advancement experimental work was performed at the University of Technology Sydney and TMOS (an Australian Research Council Centre of Excellence) led by Professor Igor Aharonovich.
Prospective and Impact of the New Technology
The shown approximate wavefront shaping of quantum emission in several degrees of flexibility could let loose the complete capacity of solid-state SPEs to be used as high-dimensional quantum sources for sophisticated quantum photonic applications.
The teams new innovation uses a new platform to use ultrathin meta-optics for approximate wavefront shaping of quantum emission in several degrees of flexibility at space temperature. It may supply new insights into the field of quantum information science. The group believes that controling photon polarisations can have a significant effect on quantum cryptography and entanglement circulation with enhanced filtering. The polarization separation is important for the future use of hBN SPEs for polarisation knotted photon pair generation.
Future Extensions and Implications
Future extension of the metalens might make it possible for the generation of high-dimensional single-photon hybrid quantum states. Any future combination of structured SPE sources with a trustworthy transmission environment, such as optical fibers, might guarantee a quantum network with higher information capability, robustness to sound, and better security.
Referral: “Arbitrarily structured quantum emission with a multifunctional metalens” by Chi Li, Jaehyuck Jang, Trevon Badloe, Tieshan Yang, Joohoon Kim, Jaekyung Kim, Minh Nguyen, Stefan A. Maier, Junsuk Rho, Haoran Ren and Igor Aharonovich, 7 August 2023, eLight.DOI: 10.1186/ s43593-023-00052-4.

Quantum emission is pivotal to recognizing photonic quantum innovations. While photon collection performance can be high, these tools can not manipulate quantum emissions. They utilized the metalens to demonstrate a multidimensional structuring of quantum emission from SPEs in hBN, running at room temperature level.
The group showed approximate shaping of the directionality of quantum emission. The teams new technology offers a brand-new platform to utilize ultrathin meta-optics for arbitrary wavefront shaping of quantum emission in numerous degrees of freedom at space temperature level.