2021-07-11

KAIST new laser system: can produce highly interactive quantum particles at room temperature

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KAIST new laser system: can produce highly interactive quantum particles at room temperature

Their findings are published in “Nature Photonics”. The findings may lead to a single microcavity laser system, which needs to be lower when the energy loss increases The threshold energy.

This system was developed by KAIST physicist Yong-Hoon Cho and his colleagues. It involves processing a single hexagonal microstructure through a loss-modulated silicon nitride substrate. Luminous cavity. The system is designed to produce polarized phonon lasers at room temperature, which is exciting because it usually requires low temperatures.

Researchers discovered another unique and counter-intuitive feature of this design. Under normal circumstances, energy will be lost during laser operation. But in this system, as the energy loss increases, the energy required to induce the laser decreases. This phenomenon can be used to develop high-efficiency, low-threshold lasers for future quantum optical devices.

“This system applies the concept of quantum physics and is called parity-time reversal symmetry,” Professor Cho said. “This is an important platform where energy loss can be used as gain. It can It is used to reduce the laser threshold energy of classical optical devices and sensors, as well as quantum devices and control the direction of light.”

The key to this platform is design and materials. The hexagonal microcavity structure divides the light particles into two different modes: one passes through the upward triangle of the hexagon, and the other passes through the downward triangle. The light particles of the two modes have the same energy and path but do not interact with each other.

However, light particles do interact with other particles called excitons, which are provided by a hexagonal microcavity made of semiconductors. This interaction leads to the production of new quantum particles called polarized phonons, which then interact to produce polarized phonon lasers. By controlling the degree of loss between the microcavity and the semiconductor substrate, an interesting phenomenon occurs, that is, as the energy loss increases, the threshold energy becomes smaller.