Holographic femtosecond laser processing with wavelength dispersion compensation

In multifocal processing with femtosecond pulses using a computer-generated hologram, a wavelength dispersion from the hologram is important issue to be solved. We propose a novel optical system to compensate the wavelength dispersion. The proposed system is composed of a pair of spatial light modulators displaying two types of hologram, one for diffracting an incoming pulse and the other for compensating an angular separation of the diffraction pulse. The system drastically reduced the focal spot distortion due to the wavelength dispersion in the reconstruction.