Cascaded Nondegenerate Four-Wave Mixing Technique for High-Power Single-Cycle Pulse Synthesis in the Visible and Ultraviolet Ranges

We present a new technique to synthesize high-power single-cycle pulses in the visible and ultraviolet ranges by coherent superposition of a multiband octave-spanning spectrum obtained by highly-nondegenerate cascaded four-wave mixing of femtosecond pulses in bulk isotropic nonresonant media. The generation of coherent spectra spanning over two octaves in bandwidth is experimentally demonstrated using a thin fused silica slide. Full characterization of the intervening multicolored fields using frequency-resolved optical gating, where multiple cascaded orders have been measured simultaneously for the first time, supports the possibility of direct synthesis of near-single-cycle 2.2 fs visible-UV pulses without recurring to complex amplitude or phase control, which should enable many applications in science and technology.Comment: 13 pages, 4 figures. Submitted to Physical Review

How emergence conditions of technological clusters affect their viability? Theoretical perspectives on cluster lifecycles

The widely studied concept of clusters has been usually treated as pre-established and successful structures. We argue that clusters are not pre-established but emerge through a double competition process of technological and regional nature. Moreover, faced to a changing environment they are not always successful. Their long-term evolution depends on their viability capacities. We show that viability is dependent on the emergence conditions, because different forms of emergence create clusters with different structures.cluster life cycle, emergence, viability, networks