Dynamic control of spatial wavelength dispersion in holographic femtosecond laser processing

Dynamic control of spatial wavelength dispersion is effective due to a potentially large spectral bandwidth of femtosecond pulses, in particular, when using sub-100-fs pulses. We demonstrate spatial wavelength dispersion control, which drastically reduces focal spot distortion in the reconstruction of a hologram, using a pair of spatial light modulators. The improved diffraction spots had nearly diffraction-limited spot sizes, agreeing well with theoretical predictions. The dynamic control of dispersion is also demonstrated in order to restrain unnecessary processing given by the zeroth-order pulse.