A compact optics configuration for the generation of donut beams for trapping atoms at the micrometer scale using a multilevel spiral-phase Fresnel zone plate (FZP) and a semiconductor laser is proposed. A FZP is designed and a multilevel spiral phase is integrated into it. A spiral-phase FZP with a radius of 1 mm and with more than 1300 half-period zones is designed with multiple angular levels for integer and fractional topological charges, and the device is fabricated using electron-beam lithography direct writing. The performance of the device is evaluated, and the generation of symmetric and asymmetric donut beams is successfully demonstrated.
© 2012 Optical Society of America
Optical Design and Fabrication
Original Manuscript: May 15, 2012
Revised Manuscript: July 13, 2012
Manuscript Accepted: July 17, 2012
Published: August 24, 2012
A. Vijayakumar and Shanti Bhattacharya, "Design, fabrication, and evaluation of a multilevel spiral-phase Fresnel zone plate for optical trapping," Appl. Opt. 51, 6038-6044 (2012)