Open AccessEffect of subwavelength annular aperture diameter on the nondiffracting region of generated Bessel beams
Author(s) -
Yuh-Yan Yu,
DingZheng Lin,
Long-Sun Huang,
ChihKung Lee
Publication year - 2009
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.17.002707
Subject(s) - optics , bessel beam , electron beam lithography , bessel function , materials science , finite difference time domain method , aperture (computer memory) , axicon , beam (structure) , diffraction , numerical aperture , depth of focus (tectonics) , lithography , physics , resist , wavelength , nanotechnology , paleontology , laser , tectonics , subduction , layer (electronics) , biology , laser beams , acoustics
A subwavelength annular aperture (SAA) made on metallic film and deposited on a glass substrate was fabricated by electron-beam lithography (EBL) and which was followed by a metal lift-off process to generate a long propagation range Bessel beam. We propose tuning the focal length and depth of focus (DOF) by changing the diameter of the SAA. We used finite-difference time domain (FDTD) simulations to verify our experimental data. We found that the position of the Bessel Beam focus spot (i.e. focal length) will be farther away from the SAA plane as the diameter of the SAA increases. In addition, the depth of focus (DOF) which is the length of the Bessel beam non-diffracting area, also increases as the diameter of the SAA expands.