Adaptive optimization of a hologram in holographic femtosecond laser processing system

In holographic parallel laser processing, precise control of diffraction peaks is important for fabricating enormous numbers of nanometer-scale structures. Although an optimized hologram has high uniformity of the peaks in a computer reconstruction, in practice, the uniformity is decreased owing to the spatial properties of the optical system. A novel optimization method based on peak intensity measurement is proposed to improve the uniformity. The method automatically incorporates the properties of the optical system into the hologram. Improved holographic femtosecond laser processing with this adaptive optimization is demonstrated. (C) 2008 Optical Society of America