The four-level diffractive triplicator has been optimized to yield the maxi
mum efficiency for such kind of a device. First, the optimization procedure
is carried out in the scalar domain, where an analytical approach is used
to obtain the values of the grating parameters. Then, a full-wave method is
adopted for the analysis of the grating in the resonance domain of the dif
fractive optics and an algorithm based on genetic evolution is used for the
maximization of its efficiency. Numerical results are presented for effici
encies and grating parameters as functions of the grating period, which are
shown to tend to those pertinent to the scalar limit when the grating peri
od is very large compared to the wavelength of the incident light.