A femtosecond pulse-shaping apparatus containing microlens arrays for use with pixellated spatial light modulators

We discuss a modified femtosecond pulse shaper that uses microlens arrays to convert the continuous band of frequencies normally obtained at the mask plane of a pulse shaper to a series of discrete spots. Two possible modified pulse-shaping geometries are described and the optimum geometry is chosen. Our experiments demonstrate that this modification can improve pulse-shaping quality when modulator arrays with large interpixel gaps are used for Fourier-plane filtering.