Fabrication of TiO2 thin film- based fresnel zone plates by nanosecond laser direct writing

Tahseen Jwad, Sunan Deng, Haider Butt, Stefan Dimov

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

Fresnel zone plates (FZPs) have been gaining a significant attention by industry due to their compact design and light weight. Different fabrication methods have been reported and used for their manufacture but they are relatively expensive. This research proposes a new low-cost one-step fabrication method that utilizes nanosecond laser selective oxidation of titanium coatings on glass substrates and thus to form titanium dioxide (TiO2) nanoscale films with different thicknesses by controlling the laser fluence and the scanning speed. In this way, phase-shifting FZPs were manufactured, where the TiO2 thinfilms acted as a phase shifter for the reflected light, while the gain in phase depended on the film thickness. A model was created to analyze the performance of such FZPs based on the scalar theory. Finally, phase-shifting FZPs were fabricated for different operating wavelengths by varying the film thickness and a measurement setup was built to compare experimental and theoretical results. A good agreement between these results was achieved, and an FZP efficiency of 5.5% to 20.9% was obtained when varying the wavelength and the oxide thicknesses of the zones.

Original languageEnglish
Article number011001
JournalJournal of Micro and Nano-Manufacturing
Volume6
Issue number1
Early online date14 Dec 2017
DOIs
Publication statusPublished - Mar 2018

Bibliographical note

Publisher Copyright:
© 2018 by ASME.

Keywords

  • Diffractive optical elements
  • Fresnel zone plate
  • Nano thin films Laser micromachinin
  • Nanosecond lasers
  • Titanium dioxide

ASJC Scopus subject areas

  • Mechanics of Materials
  • Process Chemistry and Technology
  • Industrial and Manufacturing Engineering

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