Achromatic terahertz Airy beam generation with dielectric metasurfaces

Airy beams exhibit intriguing properties such as nonspreading, self-bending, and self-healing and have attracted considerable recent interest because of their many potential applications in photonics, such as to beam focusing, light-sheet microscopy, and biomedical imaging. However, previous approaches to generate Airy beams using photonic structures have suffered from severe chromatic problems arising from strong frequency dispersion of the scatterers. Here, we design and fabricate a metasurface composed of silicon posts for the frequency range 0.4-0.8 THz in transmission mode, and we experimentally demonstrate achromatic Airy beams exhibiting autofocusing properties. We further show numerically that a generated achromatic Airy-beam-based metalens exhibits self-healing properties that are immune to scattering by particles and that it also possesses a larger depth of focus than a traditional metalens. Our results pave the way to the realization of flat photonic devices for applications to noninvasive biomedical imaging and light-sheet microscopy, and we provide a numerical demonstration of a device protocol.

Automated summary

By designing and fabricating an achromatic Airy-beam metalens, achromatic Airy beams with autofocusing and self-healing properties are successfully demonstrated, with a larger depth of focus. This paves the way for flat photonic devices for noninvasive biomedical imaging and light-sheet microscopy applications, with a numerical demonstration of a device protocol provided.