Light greatly influences human life in various angles. In physics, light transports information. For example, a light cable which converts electric signals into light is used for long-distance communication. Transportation of information using light, however, often causes a security problem. A team at Korea University (KU), led by Professor Park Hong-kyu (Department of Physics), recently presented research with a solution to the problem, the results of which were published in the renowned international journal of nanotechnology, Nano Letters.

On February 15, KU announced that Professor Park and his research team developed a single-photon source by using a compound of tungsten and selenium and deforming it locally, in collaboration with a research team at University of Illinois, led by Professor Nam Sung-woo (Department of Mechanical Science Engineering, University of Illinois). A single-photon source is critical in securing communications using light photons or particles. This is because when a single photon is transferred, it is impossible to duplicate information and it becomes clear whether there is a wiretapper. Previously, communication using light was implemented by using laser pulses, which provides a similar effect. The problem was that laser pulses are less secure, even though they allow communication similar to that using the actual photon.

The results of this research have improved the understanding of new physical phenomena and quantum information technology. Specifically, the ability to control the photon emitted from a single-photon source is the critical technology required to utilize advanced Quantum Cryptography Communication, which ensures secure communication. It can contribute to future information security techniques, which can lead to ripple effects in the fields of the military as well as the economy.

“Since the single-photon source that we developed functions at minus 270 Celsius, it was hard to maintain the temperature while carrying out experiments. Particularly, measuring whether the photons are released, one at a time, requires intense caution, so the experiment set-up had to be extremely exquisite,” stated Professor Park. The experiment was highly sensitive to vibration and noise. Furthermore, the research team had to make use of a novel sample that had never been used before because they developed a new production process. The experiment process was not simple to carry out.

“The aim is to develop a single-photon source that can be commercialized upright,” mentioned Professor Park. To achieve this, the team’s mission will be to develop the single photon source so that it will operate at ambient temperature, and with electricity which is easily accessible. The team also strives to find a single-photon source that is usable in the range of infrared rays, to permit long-distance communication.

The development of a single-photon source that can control the photons’ optical property emitted from the source has opened a new page of quantum information and communication technology. It will impact people in various ways while bringing enormous progress to the military department and in turn bringing profits to the nation. The research will change the status of the field of quantum information technology to Korean scientists, from a field comparable to a Page Not Found .

error to an accessible field; it may have laid a steppingstone for various additional studies and progresses.