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Polarization dependent spike formation on black silicon via ultrafast laser structuring

EVANGELOS SKOULAS1,2, ALEXANDROS MIMIDIS1,2, IOANNA DEMERIDOU1,3, GEORGE D. TSIBIDIS1,* , EMMANUEL STRATAKIS1,3,*

Affiliation

  1. Instituteof Electronic Structure and Laser (IESL), Foundation for Research and Technology (FORTH), N. Plastira 100, Vassilika Vouton,70013, Heraklion, Crete, Greece
  2. Materials Science and Technology Department, University of Crete, 71003 Heraklion, Greece
  3. Department of Physics, University of Crete, 71003 Heraklion-Crete, Greece

Abstract

A comparative experimental and theoretical investigation ispresented that centres on the effects of structuring black siliconsurfaceswith linearly, circularlyand azimuthallypolarized laser pulsesunder SF6ambientatmosphere.It is shown thatthe asymmetric elliptical micro-cone formationsinduced by linearlypolarized beamsresult in variable light absorptiondue to theirspatial asymmetry. By contrast, the useof azimuthallypolarized beamsleadsto an omni-directionality ofthe elliptical cone orientationwhich is dependent on thelocalelectric field during laser scanning. The locally variant electric field state that is azimuthally polarized leads to a selective conical orientationfor the induced structures. The omni-directional conical distribution induced by azimuthal polarization producessimilar,angle-independent absorption inthe visible spectrumwith thesymmetrical conical structures that could onlybe realizedwith circularly polarizedbeams..

Keywords

Femtosecond pulses, Polarization states, Spike formation, Laser-based patterning, Black silicon.

Submitted at: June 23, 2020
Accepted at: Oct. 22, 2020

Citation

EVANGELOS SKOULAS, ALEXANDROS MIMIDIS, IOANNA DEMERIDOU, GEORGE D. TSIBIDIS, EMMANUEL STRATAKIS, Polarization dependent spike formation on black silicon via ultrafast laser structuring, Journal of Optoelectronics and Advanced Materials Vol. 22, Iss. 9-10, pp. 501-509 (2020)