“…In all those studies, harmonics were observed at propagation directions not coincident with the driving pulses. Moreover the investigations reported in [3,4], performed in the strong interaction regime with multiple intense beams, showed that the harmonic radiation was spectrally dispersed, namely different harmonics propagated at different directions. In this work we report on a novel regime of HHG by multiple intense beams, where the harmonics are produced by three synchronized, intense and ultrashort laser pulses arranged in a non-planar geometry.…”