Nonparaxial imaging using terahertz structured light

It is shown that structured nonparaxial terahertz (THz) light in the form of Gaussian, Bessel and Airy beams can be generated using exclusively silicon diffractive optics elements fabricated by femtosecond laser ablation technology. The accelerating nature of the structured light is demonstrated via THz imaging of objects partially obscured by a metallic obstacle. Lensless nonparaxial beam generation and application in THz imaging of single objects and stacked graphene layers are presented and discussed. Benchmarking revealed that the use of structured THz light in imaging consistently outperforms the conventional one in terms of resolution and contrast.