Selenium nanofilm capable of detecting circular polarization &#40;Provided by KAIST&#41; / News1

KAIST (Korea Advanced Institute of Science and Technology) announced on Wednesday that a research team led by Professor Ji Hyun Yeom from the Department of Materials Science and Engineering has developed the world's first semiconductor material capable of detecting CIRCULARLY POLARIZED LIGHT (CPL) across a broad spectrum—from ultraviolet to short-wavelength infrared—by precisely controlling the chiral structure of selenium (Se) nanocrystals at the atomic level.

Chirality refers to the left-right asymmetry and is a crucial physical property, not only in molecular chemistry but also in fields such as optics, medicine, and biological systems. It is particularly critical in detecting CPL, which carries the SPIN ANGULAR MOMENTUM of light.

The team's new technology is a Film-type semiconductor material that can detect circularly polarized light (CPL) with high sensitivity at room temperature. This opens the door for real-world applications in quantum computing, Spintronics, and optical sensing, such as decoding encrypted optical data or controlling quantum bits (qubits).

Conventional CPL sensors have struggled with moisture and UV degradation, which has hindered their commercial viability. To overcome this, the KAIST team focused on selenium, an inorganic material with a naturally asymmetric crystal structure and HIGH STABILITY. However, in its natural form, selenium contains a mixture of left- and right-handed atomic orientations, making it difficult to isolate one direction for functional use.

To resolve this, the researchers developed a "Chirality Transition Technology" that transforms selenium into NANO-RODS with a controlled chiral lattice structure.

When assembled into a thin film, the selenium nanofilm successfully detected CPL over a wide wavelength range, and it accurately distinguished the direction of polarization without the need for additional polarizing filters.

Their experiments also confirmed that the device remains functional and stable for over 13 months in open air, with no degradation in performance.

Professor Yeom commented, "This study introduces a new approach to achieving and analyzing chirality in semiconductor optical materials. It has the potential to evolve into a core technology for a variety of applications, including quantum optics, secure optical communications, biomedical diagnostics, and high-end image sensing."

The research was published online in the international journal <em>Nature Communications</em>.

KAIST (Korea Advanced Institute of Science and Technology) announced on Wednesday that a …

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