Broadband frequency tripling based on segmented partially deuterated KDP crystals

We report a novel frequency tripler for efficient conversion of broadband high- power laser pulses at 1 mu m. The deuteration level can be used as a degree of freedom to alter the phase- matching wavelength of a partially deuterated KDP crystal. It is shown that a segmented partially deuterated KDP crystal with discrete values of deuteration is capable of enhancing the acceptance bandwidth of frequency tripling. A five- segment design is presented, which is applicable to the efficient frequency tripling of uncompressed chirped pulses with a bandwidth of similar to 4 nm, and hence suitable for a Nd: glass petawatt laser system. The tolerances on the design parameters are also evaluated.