KRISS Develops Room-Temperature Single-Photon Source Operable with Plug-and-Play Power Connection [Reading Science]

Operates on 220V Power Without Cryogenic Cooling Equipment

Localization of Core Quantum Cryptography Components

Commercialization in Collaboration with Curad

The Korea Research Institute of Standards and Science (KRISS) has taken a significant step toward the localization of core components for quantum communication by developing a room-temperature single-photon source that operates without the need for ultra-low temperature equipment.

On June 18, KRISS announced that it had implemented a single-photon source based on gallium nitride (GaN) semiconductor technology as a compact device compatible with a 19-inch rack. This technology adopts a plug-and-play approach, allowing immediate use with a standard 220V power connection. As such, it significantly enhances the practical application of quantum light source technology outside of the laboratory.

The Korea Research Institute of Standards and Science (KRISS) developed the "room-temperature plug-and-play single-photon light source." The research team integrated key optical and electronic components, such as a high-magnification lens for detecting single photons, a stray light elimination filter, and an optical fiber coupling device, into a 19-inch rack-type equipment. This implementation enables the generation of single photons without the need for ultra-low temperature cooling devices or large optical experimental tables. Photo by KRISS

A single-photon source is a device that generates individual photons, the smallest unit of light, and serves as a key component in photon-based quantum technologies such as quantum communication, quantum sensing, and quantum measurement. In particular, quantum cryptography relies on encoding information in photons; any eavesdropping attempt alters the photon’s state, allowing immediate detection of intrusions.

However, conventional single-photon sources require extremely low temperatures of around minus 270 degrees Celsius, large-scale optical experimental setups, and highly specialized research personnel, making industrial deployment challenging.

Quantum Light Source Breaking Free from Cryogenic Labs

The research team achieved stable generation of single photons at room temperature by utilizing atomic-scale defects that naturally form inside the gallium nitride semiconductor.

The core technology is "Spatial Deterministic Mapping." Because these internal defects are extremely small and randomly distributed within the semiconductor, it is difficult to repeatedly use the exact same location. The researchers addressed this by recording the coordinates of locations where single photons are emitted, enabling the device to automatically relocate these sites even after being powered off and on.

Additionally, a collaborative team led by Professor Lee Ukjae at Kongju National University designed and fabricated a nanometer-scale circular Bragg grating structure on the semiconductor surface, increasing the efficiency of photon emission to the outside.

The device developed by the research team is built to the 19-inch rack standard, allowing easy integration with existing quantum key distribution (QKD) equipment and facilitating deployment in telecommunications networks and security facilities.

With the global competition for quantum technology leadership intensifying—particularly in the United States, China, and Europe—securing core equipment and components has become a pivotal element of national competitiveness. This achievement is regarded as a leading example of the localization of quantum parts, materials, and equipment by commercializing a single-photon source with domestic technology.

Developers of the room-temperature single-photon light source. From the front left, clockwise: Paeinho Bae, Principal Researcher at KRISS; Kiseok Hong, Principal Researcher at KRISS; Donghun Lee, CEO of Curad Co., Ltd.; Junho Park, Senior Researcher at KRISS; Seondo Lim, Head of Photometry Measurement Group at KRISS. Provided by KRISS

Looking ahead, the technology is expected to be applied to highly secure communication infrastructures such as financial networks, medical networks, and government-exclusive networks. KRISS is currently working on commercializing the product in collaboration with its spin-off company, Curad Co., Ltd.

Hong Kisuk, Principal Researcher at KRISS, commented, "A single-photon source is an essential component of photon-based quantum technologies, but until now it has been confined to cryogenic laboratories. This achievement is significant because it delivers a rack-mounted light source operable at room temperature, lowering the barrier for field applications."

Lee Donghun, CEO of Curad Co., Ltd., stated, "The competitiveness of the quantum industry hinges on the ability to develop and stably supply core components in-house. We aim to contribute to building a domestic supply chain for quantum light sources based on Korean technology."

Meanwhile, the research on improving photon extraction efficiency, which underpins this achievement, was jointly conducted by the KRISS Radiometry Group and the Department of Data and Information Physics at Kongju National University. The results were published in the international optics journal "Laser & Photonics Reviews."

This content was produced with the assistance of AI translation services.