Binary square axicon with chiral focusing properties for optical trapping

Balasubramani Vinoth*, Anand Vijayakumar, Mani Ratnam Rai, Joseph Rosen, Chau Jern Cheng, Oleg V. Minin, Igor V. Minin

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


We introduce a novel phase-only diffractive optical element called chiral binary square axicon (CBSA). The CBSA is designed by linearly rotating the square half-period zones of the binary square axicon with respect to one another. A quadratic phase mask (QPM) is combined with the CBSA using modulo-2πphase addition technique to bring the far-field intensity pattern of CBSA at the focal plane of the QPM and to introduce quasiachromatic effects. The periodically rotated zones of CBSA produce a whirlpool phase profile and twisted intensity patterns at the focal plane of QPM. The degree of twisting seen in the intensity patterns is dependent upon the angular step size of rotation of the zones. The intensity pattern was found to rotate around the optical axis along the direction of propagation. The phase patterns of CBSA with different angles of zone rotation are displayed on a phase-only spatial light modulator, and the experimental results were found to match with the simulation results. To evaluate the optical trapping capabilities of CBSA, an optical trapping experiment was carried out and the optical fields generated by CBSA were used for trapping and rotating yeast cells.

Original languageEnglish
Article number041204
JournalOptical Engineering
Issue number4
Publication statusPublished - 2020 Apr 1


  • diffractive optical elements
  • optical trapping
  • spatial light modulators

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • General Engineering


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