Proc. SPIE, doi:10.1117/12.2253983

• “Beam shaping by spatial light modulator and 4f system to square and top-flat for interference laser processing.”
• Kazuhito Osawa, Masataka Yoshida, Yoshiki Nakata, Noriaki Miyanaga, Aiko Narazaki, Tatsuya Shoji, Yasuyuki Tsuboi

• Proc. SPIE
• DOI: 10.1117/12.2253983

We demonstrated beam shaping to top-flat and square by phase-only Spatial Light Modulator (SLM) and spatial frequency filtering. Spatial phase distribution of a femtosecond laser beam was modulated by a phase grating pattern reflecting a transfer function for beam shaping. By filtering the higher spatial frequency component at Fourier plane in 4f system, the spatial amplitude distribution of the zero-order beam was shaped to top-flat and square. This result enables us to fabricate large area and uniform devices by using multi-shot processing.