Intense supercontinuum generation in the near-ultraviolet range from a 400-nm femtosecond laser filament array in fused silica

An intense supercontinuum (SC) in the near-ultraviolet range is generated from filamentation by focusing a 400-nm laser into fused silica with a microlens array (MLA). The spectrum of the SC is shown to be sensitive to the distance between the MLA and fused silica. In our optimal conditions, the near-ultraviolet SC can cover a range of 350–600 nm, where a bandwidth of approximately 55 nm above the 1μ J/nm spectral energy density and 20 nm bandwidth with tens ofμJ/nm are achieved. In addition, the energy conversion efficiency of the 400 nm laser for SC generation is further analyzed. A maximum conversion efficiency of 66% is obtained when the entrance face of fused silica is set around the focus of the MLA.