Speaker
Description
We demonstrate compact terahertz (THz) components that combine a photonic crystal waveguide with a plasmonic bull’s-eye coupler. The waveguide, formed by a pattern of laser-written holes that extend through the thickness of a GaP window, allows efficient THz generation through optical rectification of a co-propagating near-infrared pulse. A similar waveguiding structure allows sensitive guided-wave detection via electro-optic sampling. These THz components address key limitations of free-space THz systems, including phase mismatch, short interaction lengths, weak mode overlap, and alignment sensitivity.
The waveguide is engineered to tailor the effective refractive index of the THz mode, achieving velocity matching with a co-propagating near-infrared pulse. This design increases optical-to-THz conversion efficiency by extending the coherence length beyond that of bulk GaP. The plasmonic bull’s-eye antenna further enhances performance by concentrating incident THz fields into a small interaction volume and coupling them efficiently into the guided mode.
We demonstrate this concept with broadband and tunable THz generation and detection from 1.9 to 3.9 THz. Significant improvements are observed in comparison to results obtained with a bulk GaP crystal.
All structures are fabricated directly in bulk GaP using femtosecond laser writing, enabling precise three-dimensional patterning at the micrometer scale. This scalable and versatile fabrication approach allows rapid prototyping while ensuring consistent, reliable device performance. The resulting platform provides a compact, high-performance solution for both THz generation and detection, with strong relevance for next-generation high-speed wireless communication systems.
| Keyword-1 | Nonlinear optics |
|---|---|
| Keyword-2 | THz photonics |
| Keyword-3 | THz source and detector |