Destructive interference of laser harmonics in mixtures of various emitters in plasma plumes

We analyzed the interference of two high-order harmonic generation processes in mixtures of different materials. These studies were carried out using mixtures of silver and gold nanoparticle suspensions, as well as mixtures of boron and carbon. These samples were ablated using picosecond pulses and probed by femtosecond pulses. While the harmonic cutoffs remained approximately the same for the mixtures and the separate ingredients, the conversion efficiency in the case of plasma plumes containing the mixtures of the above materials noticeably decreased around all spectral ranges of harmonic generation. These studies show that destructive interference in these media dominates over constructive interference.