We present a series of sub-wavelength annular aperture (SAA) structures with annular width equal to the tip of a tapered hollow tube, which was fabricated using a heat-pulled method. The light beams emitted from the SAA-like structures created by the tapered hollow tube produced light beams characteristic of Bessel beams. We obtained a sub-micrometer focal spot with a depth-of-focus larger than 7 μm and identified the proper structure parameters needed to generate Bessel-like light beams. Our new design has potential application to areas such as optical lithography, optical trapping, and the fabrication of high aspect ratio structures.
© 2012 Optical Society of America
Diffraction and Gratings
Original Manuscript: September 5, 2012
Revised Manuscript: October 1, 2012
Manuscript Accepted: October 1, 2012
Published: October 30, 2012
Chun-Yen Chen, Yu-Hsun Lee, Chih-Jen Chien, Ming-Han Chung, Yuh-Yan Yu, Te-Hsun Chen, and Chih-Kung Lee, "Generating a sub-wavelength Bessel-like light beam using a tapered hollow tube," Opt. Lett. 37, 4537-4539 (2012)