Truncated Gaussian-Bessel beams for short-pulse processing of small-aspect-ratio micro-channels in dielectrics

Xing Liu (1) , Qingfeng Li (2) , Aurélien Sikora (2) , Marc Sentis (2) , O. Uteza (2) , Razvan Stoian (3) , W Zhao (1) , G Cheng (1) , N. Sanner (2)

1 State Key Laboratory of Transient Optics and Photonics, Xian Institute of Optics and Precision Mechanics
2 LP3 - Laboratoire Lasers, Plasmas et Procédés photoniques
3 LHC - Laboratoire Hubert Curien

In order to control the length of micro-channels ablated at the surface of dielectrics, we use annular filtering apertures for tailoring the depth of focus of micrometric Gaussian-Bessel beams. We identify experimentally and numerically the appropriate beam truncation that promotes a smooth axial distribution of intensity with a small elongation, suitable for processing micro-channels of small aspect ratio. Single-shot channel fabrication is demonstrated on the front surface of a fused silica sample, with sub-micron diameter, high-quality opening, and depth of few micrometers, using 1 ps low-energy (< 0.45 µJ) pulse. Finally, we realize 10 × 10 matrices of densely packed channels with aspect ratio ~5 and a spatial period down to 1.5 μm, as a prospective demonstration of direct laser fabrication of 2D photonic-crystal structures.

Domaines: Science des matériaux [cond-mat.mtrl-sci]; Optique [physics.optics]; Physique des plasmas [physics.plasm-ph]

Xing Liu, Qingfeng Li, Aurélien Sikora, Marc Sentis, O. Uteza, et al.. Truncated Gaussian-Bessel beams for short-pulse processing of small-aspect-ratio micro-channels in dielectrics. Optics Express, 2019, 27 (5), pp.6996. ⟨10.1364/OE.27.006996⟩. ⟨hal-02138270⟩