Patterned two-photon illumination by spatiotemporal shaping of ultrashort pulses.

Multiphoton excitation by temporally focused pulses can be combined with spatial Fourier-transform pulse shaping techniques to enhance spatial control of the excitation volume. Here we propose and demonstrate an optical system for the generation of such spatiotemporally engineered light pulses using a combination of spatial control by a two-dimensional reconfigurable light modulator, with a dispersive optical setup for temporal focusing. We show that although the properties of a holographic beam significantly differ from those of plane-wave illumination used in previous temporal focusing realizations, this leads only to a slightly reduced axial resolution. We show that the system can provide scanningless, arbitrarily shaped, depth resolved excitation patterns that offer new perspectives for multiphoton photoactivation and optical lithography applications.