The block OCTFilter describes the type and shape of the filter function
that are applied to the optimized laser field in each iteration.
The filter forces the laser field to obtain the given form in frequency space.
Each line of the block describes a filter; this way you can actually have more
than one filter function (e.g. a filter in time and two in frequency space).
The filters are applied in the given order, i.e., first the filter specified
by the first line is applied, then second line.
The syntax of each line is, then:
domain | function
Possible arguments for domain are:
(i) frequency_filter: Specifies a spectral filter.
(ii) time_filter: DISABLED IN THIS VERSION.
time | "exp(-80*( w + 0.1567 )^2 ) + exp(-80*( w - 0.1567 )^2 )"
Be careful that also the negative-frequency component is filtered since the resulting
field has to be real-valued.
The filter is applied in the frequency domain.