Laser ablation of silicon using a Bessel-like beam generated by a subwavelength annular aperture structure

Yuh-Yan Yu; Chin-Kai Chang; Ming-Wei Lai; Long-Sun Huang; Chih-Kung Lee

doi:10.1364/AO.50.006384

Laser ablation of silicon using a Bessel-like beam generated by a subwavelength annular aperture structure

Appl Opt. 2011 Dec 1;50(34):6384-90. doi: 10.1364/AO.50.006384.

Authors

Yuh-Yan Yu¹, Chin-Kai Chang, Ming-Wei Lai, Long-Sun Huang, Chih-Kung Lee

Affiliation

¹ Institute of Applied Mechanics, National Taiwan University, Taipei 10617, Taiwan.

PMID: 22192990
DOI: 10.1364/AO.50.006384

Abstract

Using a femtosecond laser incident to an oxide-metal-oxide film engraved with a subwavelength annular aperture (SAA) structure, we generated a Bessel-like beam to ablate silicon. Experimental results show that the silicon can be ablated with a 0.05 J/cm(2) input ablation threshold at 120 fs pulse duration. We obtained a surface hole possessing a diameter less than 1 μm. Optical performance, including depth-of-focus and focal spot of the SAA structure, were simulated using finite-different time-domain calculations. We found that a far-field laser beam propagating through a SAA structure possesses a submicrometer focal spot and high focus intensity. Our method can be easily adopted for surface machining in microfabrication applications.