Open AccessSynthesis of sub-diffraction quasi-non-diffracting beams by angular spectrum compression
Author(s) -
Shuo Zhang,
Hao Chen,
Zhixiang Wu,
Kun Zhang,
Yuyan Li,
Gang Chen,
Zhihai Zhang,
Zhongquan Wen,
Luru Dai,
and Lingfang Wang
Publication year - 2017
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.25.027104
Subject(s) - optics , diffraction , angular spectrum method , wavelength , lens (geology) , physics , diffraction grating , beam (structure) , diffraction efficiency , transverse plane , radius , grating , materials science , computer science , computer security , structural engineering , engineering
Quasi-non-diffracting beams are attractive for various applications, including optical manipulation, super-resolution microscopes, and materials processing. However, it is a great challenge to design and generate super-long quasi-non-diffracting beams with sub-diffraction and sub-wavelength size. In this paper, a method based on the idea of compressing a normalized angular spectrum is developed, which makes it possible and provides a practical tool for the design of a quasi-non-diffracting beam with super-oscillatory sub-wavelength transverse size. It also presents a clear physical picture of the formation of super-oscillatory quasi-non-diffracting beams. Based on concepts of a local grating and super-oscillation, a lens was designed and fabricated for a working wavelength of λ = 632.8 nm. The validity of the idea of normalized angular spectrum compression was confirmed by both numerical investigations and experimental studies. An optical hollow needle with a length of more than 100λ was experimentally demonstrated, in which an optical hollow needle was observed with a sub-diffraction and sub-wavelength transverse size within a non-diffracting propagation distance of 94λ. Longer non-diffracting propagation distance is expected for a lens with larger radius and shorter effective wavelength.