Enhanced Sub‐Terahertz Microscopy based on Broadband Airy Beam

Abstract Non‐diffraction electromagnetic beams such as Airy beams attract wide exploration in various disciplines owing to its fascinating features and great potential of applications. Although generation and applications of Airy beams are actively studied in the optical regime, applications of Airy beams in the THz or sub‐THz domain are rarely explored. This work proposes a new microscopic technique leveraging a sub‐THz broadband non‐diffraction Airy beam as the illumination beam to improve the image quality, which is named as enhanced sub‐THz microscopy (ESTM). The effectiveness of the ESTM is validated by a metallic sample, which shows that applying broadband measured information can render a better image quality than only using single‐frequency information. By blocking the sample using a scattering obstacle, it is demonstrated that the self‐reconstruction property of the Airy beam can efficiently suppress the distortion induced by the obstacle and good images can still be obtained. In addition, it is shown that the image quality applying a broadband Airy beam is superior to that of non‐diffraction quasi‐Bessel beams and other conventionally used illumination beams for microscopic technique.