Product Code: ICAL07_M103

Femtosecond Laser Micro-Structuring of Materials in the NIR and UV Regime
Authors:
D. Liu, The University of Liverpool; Liverpool Great Britain
J. Cheng, The University of Liverpool; Liverpool Great Britain
Walter Perrie, The University of Liverpool; Liverpool Great Britain
A. Baum, The University of Manchester; Manchester Great Britain
Martin Sharp, The University of Liverpool; Liverpool Great Britain
P. Scully, The University of Manchester; Manchester Great Britain
Stuart Edwardson, The University of Liverpool; Liverpool Great Britain
N. Semaltianos, The University of Liverpool; Liverpool Great Britain
Z. Kuang, The University of Liverpool; Liverpool Great Britain
P. French, The University of Liverpool; Liverpool Great Britain
Geoff Dearden, The University of Liverppol; Liverpool Great Britain
Ken G. Watkins, The University of Liverpool; Liverpool Great Britain
Lin Li, The University of Manchester; Manchester Great Britain
Presented at ICALEO 2007

Ultrafast laser micro-structuring of ceramic alumina, titanium and stainless steel are presented confirming that precision, melt free micro-structuring is indeed possible with intense femtosecond optical pulses. While metals are best machined at a fluence a few times ablation threshold, ceramic alumina, on the other hand shows excellent structuring with no evidence of melt at high fluence F ~ 21Jcm-2. In PMMA, at 387nm with pulselength ~ 200fs, we demonstrate refractive index modification within the bulk induced by two photon absorption to generate phase gratings. By using a holographic technique combined with 387nm femtosecond radiation and 0.5NA UV objective, sub-micron pitch periodic structures were ablated on stainless steel, titanium and silicon. With a lower (0.15NA) objective and focussing the periodic optical field distribution within bulk PMMA, micron pitch phase gratings can be generated.