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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-27 9:31 |
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Conference: Bucharest University Faculty of Physics 2014 Meeting
Section: Optics, Spectroscopy, Plasma and Lasers
Title:
Fabrication of photonic crystal structures by femtosecond laser ablation on TiO2 films
Authors:
Iulia ANGHEL(1,2), F. JIPA(1,2), Andreea ANDREI(1), S. SIMION(1), R. DABU(1), M. ZAMFIRESCU(1)
Affiliation:
1) National Institute for Laser, Plasma and Radiation Physics, Atomistilor 409, 077125 Magurele, Romania.
2) University of Bucharest, Faculty of Physics, Atomistilor 405, 077125 Magurele, Romania
E-mail
iulia.anghel@inflpr.ro
Keywords:
Femtosecond laser ablation
Titanium dioxide
Photonic bandgap structure
Abstract:
A photonic structure on TiO2 thin films was designed to show photonic band gap (PBG) in the near-infrared range, at the telecommunication wavelengths. The periodical structure was produced by femtosecond laser ablation. The plane wave expansion method was used to compute the photonic band gap of the laser ablated structure. The impact of limited laser processing accuracy on the photonic band gap has been studied as variation of the radius of the holes. The structure was produced by tightly focused femtosecond laser beam in multi-pulses ablation regime, using a Ti:Sapphire CPA laser system with pulse duration of 200 fs and energy per pulse of tens of nJ for a focusing optics with numerical apperture NA = 0.5. The optimum irradiation conditions were found as folowing: number of pulse N = 15 and laser beam energy E = 58 nJ. The resulting periodic stucture has an estimated photonic bangap centered at 1.53 m with a bandwidth of about 42 nm.
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