Researchers Unlock Tunable Chirality in Radiation Light
New methods for manipulating electron beams enable selective handedness in light emitted from silicon grating structures.
Updated on Oct. 23, 2026 in Physics
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Researchers in Singapore and China have demonstrated that Smith-Purcell radiation inherently possesses chirality, a property that was previously obscured by symmetrical cancellations. This discovery allows for the tunable emission of chiral light by manipulating electron beams and silicon grating geometries.
Why it matters
Understanding this inherent chirality enables the development of tunable light sources for high-precision applications like extreme ultraviolet lithography. By breaking the symmetry of these emitters, physicists can now harness specific handedness in radiation that was previously dismissed as balanced.
Experiments achieved a chirality value of 0.87 using 100 nanometre grating pitches, compared to 0.726 at 120 nanometres. The emitted light is tunable across a 450 to 900 nanometre wavelength range, with simulations indicating potential chirality values up to 0.98 via beam shifting.
The players
Singapore University of Technology and Design
An academic institution focused on research in engineering and design, serving as the site for the lead research team.
The details
Smith-Purcell radiation occurs when an electron beam passes near a periodic grating, causing the electrons to oscillate and emit light. Researchers found that rotating the grating relative to the beam or shifting the beam toward one edge breaks the spatial symmetry that previously caused left-handed and right-handed components to cancel each other out. These tests were conducted inside a scanning electron microscope, which images surfaces using a focused beam of electrons.
Timeline
1953: Physicists first identified the Smith-Purcell radiation phenomenon.
- 2026-10-23
Researchers demonstrated tunable chiral light emission.
The Tech Race
This finding builds on the fundamental 1953 discovery of Smith-Purcell radiation by correcting a long-standing oversight regarding the symmetry of the emission. The team is now moving to refine the technique, aiming for higher chirality values that could eventually challenge existing light-source standards in lithography.
While current results are limited to laboratory environments, these findings represent a shift in the potential utility of electron-beam radiation sources. Future iterations may impact the precision of extreme ultraviolet lithography, a critical manufacturing process for advanced semiconductors.
The takeaway
The study clarifies that chiral light can be extracted from standard grating structures by simple mechanical adjustments. Future research will track whether these structures can maintain efficiency at the higher electron energies required for X-ray generation.
Further reading
Explore more developments in Physics and the fundamental principles driving modern light-source research.
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