Efficient broadband sum frequency based on controlled phase-modulated input fields: theory for 351-nm ultrabroadband or ultrashort-pulse generation

Abstract

A new method of efficient sum-frequency generation for broadband input fields is proposed and analyzed. It involves the mixing of controlled phase-modulated waves for phase matching over a broad bandwidth. Regardless of the form of the modulation, phase matching can be maintained over the whole pulse duration, provided that the ratio of the chirp parameters of the incident waves is correctly chosen, thereby driving highly efficient sum-frequency generation. The case of 1.05-μm frequency tripling with KDP crystals is analyzed in detail and is shown to be applicable to the efficient generation of either broadband nanosecond pulses or ultrashort and intense pulses at 351 nm.