Satoshi HASEGAWA^* and Yoshio HAYASAKI

Department of Optical Science and Technology, Faculty of Engineering, The University of Tokushima, 2-1 Minamijosanjima-cho, Tokushima 770-8506, Japan

(Received February 2, 2007; Accepted April 27, 2007)

Parallel femtosecond laser processing with a computer-generated hologram displayed on a spatial light modulator (SLM) is demonstrated. Use of the SLM enables performance of an arbitrary and variable patterning in laser processing. The hologram uses multiplexed phase Fresnel lenses (MPFLs) with features of independent tunability, three-dimensional (3D) parallelism of the diffraction peaks, optimization of the hologram with low computational costs, and low contribution of zero-order light to the processing. To make uniform the reconstructed diffraction peaks, an MPFL is optimized by changing the center phase and size of each phase Fresnel lens while taking account of the intensity distribution of the irradiated laser pulse and the spatial frequency response of an SLM. Using the holographic technique, two-dimensional parallel processing with a single-pulse irradiation of glass is demonstrated and the processing performance is analyzed.

Key words: femtosecond laser processing, computer-generated hologram, spatial light modulator, phase Fresnel lens

^*E-mail address: hasegawa_s@opt.tokushima-u.ac.jp