Shaping Ultrafast Optical Pulses with Liquid Crystal Spatial Light Modulators

Ultrashort pulses are routinely used to excite dynamic processes in quantum-mechanical
systems. The shape of the temporal intensity envelope plays a large role in the excitation
dynamics, and hence the outcome of the process. The ability to “coherently control” or
drive an experiment with a shaped optical field is one of the most intriguing applications
in the field of ultrafast phenomena today.

However, even if coherent control isn’t the goal, there are pragmatic reasons to consider
programmable pulse shape control when using femtosecond lasers. A pulse shaper
provides the ultimate control in terms of dispersion and amplitude compensation. The
pulse shaper can be used to ensure that the pulse delivered on target is precisely the
desired pulse, e.g., it can effectively pre-compensate for dispersive optics. This is
especially useful if the optical dispersion changes during the experiment as it can for
example, in multiphoton microscopy.