A nonlinear metasurface has produced widely tunable, continuous-wave terahertz emission at room temperature, pointing to a compact route into a spectral range that has long resisted efficient sources.
The advance comes from careful metasurface engineering that strengthens nonlinear emission, avoiding the need for bulkier or more restrictive terahertz-generation setups.
Nature Photonics highlighted the result as a way to bridge the terahertz gap, where practical sources have remained difficult despite years of work across photonics and materials research.
If scalable, the approach could widen access to tunable terahertz devices for spectroscopy, imaging and communications by shrinking source size while preserving continuous-wave operation.