Diffractive multi-beam surface micro-processing using 10 ps laser pulses

A high repetition rate picosecond laser system is combined with a spatial light modulator (SLM) for diffractive multiple beam processing. The effect of the zero order beam is eliminated by adding a Fresnel zone lens (FZL) to defocus the un-diffracted beam at the processing plane. Chromatic dispersion, which is evident with a large bandwidth femtosecond pulses leading to the problem of distorted hole shape is eliminated due to the much narrower spectral bandwidth, � 0.1 nm at 10 ps pulselength, resulting in highly uniform intensity spots, independent of diffraction angle. In addition, high-throughput processing is demonstrated by combining the high power laser output, 2.5 W at l � 1064 nm and fast repetition rate, f � 20 kHz with P > 1.2 W diffracted into 25 parallel beams. This has the effect of creating an ‘‘effective’’ repetition rate of 500 kHz without restrictive scan speeds.

[1]  Nobuo Nishida,et al.  Variable holographic femtosecond laser processing by use of a spatial light modulator , 2005 .

[2]  A. Tünnermann,et al.  Femtosecond, picosecond and nanosecond laser ablation of solids , 1996 .

[3]  C. Fotakis,et al.  Efficient femtosecond laser micromachining of bulk 3C-SiC , 2005 .

[4]  Stuart Edwardson,et al.  Fast parallel diffractive multi-beam femtosecond laser surface micro-structuring , 2009 .

[5]  Friedrich Dausinger,et al.  Machining of metals with ultrashort laser pulses: from fundamental investigations to industrial applications , 2005, International Symposium on High Power Laser Systems and Applications.

[6]  Shuhei Tanaka,et al.  Arbitrary micropatterning method in femtosecond laser microprocessing using diffractive optical elements. , 2004, Optics express.

[7]  Stuart Edwardson,et al.  High throughput diffractive multi-beam femtosecond laser processing using a spatial light modulator , 2008 .

[8]  Yoshio Hayasaki,et al.  Sparse-exposure technique in holographic two-photon polymerization. , 2008, Optics express.

[9]  Gerard Mourou,et al.  Laser‐induced breakdown by impact ionization in SiO2 with pulse widths from 7 ns to 150 fs , 1994 .

[10]  Johannes Courtial,et al.  Interactive approach to optical tweezers control. , 2006, Applied optics.

[11]  Bianca Schreder,et al.  Femtosecond laser-induced refractive index modification in multicomponent glasses , 2005 .

[12]  G. Mourou,et al.  Laser ablation and micromachining with ultrashort laser pulses , 1997 .

[13]  Yoshio Hayasaki,et al.  Holographic femtosecond laser processing using optimal-rotation-angle method with compensation of spatial frequency response of liquid crystal spatial light modulator. , 2007, Applied optics.

[14]  H. Tiziani,et al.  Multi-functional optical tweezers using computer-generated holograms , 2000 .

[15]  Joachim P Spatz,et al.  Symmetry dependence of holograms for optical trapping. , 2005, Optics letters.

[16]  N. G. Semaltianos,et al.  Single-pulse drilling study on Au, Al and Ti alloy by using a picosecond laser , 2009 .

[17]  Nobuo Nishida,et al.  Holographic femtosecond laser processing with multiplexed phase Fresnel lenses. , 2006, Optics letters.

[18]  Jean-François Guillemoles,et al.  Comparative investigation of solar cell thin film processing using nanosecond and femtosecond lasers , 2006 .