New nano-device for generating structured light for advanced applications developed

Researchers have developed a tiny, room-temperature device that creates a special type of structured light called radially polarized photons, which are highly useful for secure communication, advanced imaging, and precision optical tools. By carefully designing and positioning a quantum dot within a nanoantenna, they achieved high-quality light with over 93% polarization purity. This breakthrough helps improve the efficiency and practicality of devices that use structured light, paving the way for advancements in communication and optical technology.

A team led by Prof. Ronen Rapaport  from the Racah School of Physics at The Hebrew University of Jerusalem has developed a new device that produces radially polarized photons at room temperature. This advancement offers new possibilities for both classical and quantum communication technologies.

Radially polarized light has a unique electric field structure that makes it useful for a range of applications, including secure communication, advanced imaging, and precision optical tools. Producing this type of light reliably, especially in nano-photonic systems, has been a technical challenge.

The team addressed this challenge by combining a “giant” CdSe/CdS colloidal nanocrystal (about 20 nanometer in diameter) with a hybrid metal-dielectric nanoantenna. The quantum dot is precisely placed on a tiny metal nanocone at the center of the antenna, which allows the device to generate photons with a radial polarization purity of more than 93%. The system works efficiently at room temperature and is only 10 microns wide, compact enough for potential integration into on-chip technologies.

“The accurate positioning of the quantum dot plays a key role in achieving high-quality light output,” said Prof. Rapaport. “This study helps us better understand how to control light polarization in small-scale devices, which is important for future quantum applications.”

The research combines experimental data and simulations to provide insights into how nanostructures can enhance photon emission and polarization. These findings may help advance the design of nano-photonic devices for use in secure communication and other emerging technologies.