PhD Physics Dissertation Defense: Generation of Periodic Beams with a Volume Holographic Axicon by Alvie Asuncion

ateneophysicsnews_alvie_asuncion_dissertation_defense_20170503

The Department of Physics of Ateneo de Manila University cordially invites you to a dissertation defense:

  • Dissertation title: GENERATION OF PERIODIC BEAMS WITH A VOLUME HOLOGRAPHIC AXICON
  • PhD Physics Candidate: Alvie Asuncion
  • Schedule and venue: May 4, 4 PM, F106

Dissertation panel

  • Dr. Raphael A. Guerrero (Physics), Dissertation Adviser
  • Dr. Paul Leonard Atchong C. Hilario (UPD), Dissertation Examiner
  • Dr. Marienette Vega (Physics), Dissertation Examiner
  • Dr. Mikaela Irene D. Fudolig (Physics), Dissertation Reader
  • Dr. Joel T. Maquiling (Physics), Dissertation Reader

Abstract

Superimposed Bessel beams (SBBs), which exhibit periodic behavior along the propagation axis, have been found useful in optical micromanipulation, atom trapping, laser drilling and other applications. The oscillating core diameter of such beams gained attention due to a pre-defined longitudinal pattern, which can be modified by varying certain experimental parameters. In this study, photorefractive volume holography is employed to generate SBBs with tunable periodicity. This is performed by using an axicon-telescope (a-t) system to generate quasi-Bessel beams (QBBs) with different transverse profiles corresponding to different cone angles. The generated QBBs are recorded as a thick hologram in a LiNbO3 photorefractive crystal. Stored holograms were considered as equivalent to a volume holographic axicon that effectively transforms the profile of Gaussian readout beams into QBBs. Retrieved QBBs from the crystal are focused by the original axicon to produce SBBs. Results show that both the QBB profile and the SBB period can be tuned by simply varying the a-t distance d. SBB oscillation periods that range from 4.3 cm to 6.1 cm were obtained. The method presented in this study allows tunability of SBB period through a simple rearrangement of optical elements.

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