Abstract:

We present an experimental treatment for the super-continuum (SC) generated through a hollow-core fiber by a nanosecond pulse launched from a Q-switched microchip Nd³⁺:YAG/Cr⁴⁺:YAG laser. The SC spectrally spans over a half-octave in near IR (~1.0–1.5 µm) and is attainable yet at fairly moderate fiber length (tens of cm). The SC generation process is shown to originate from silica nodes of the fiber cladding (“secondary cores”), where the pump radiation is tightly focused, and to be triggered out by a four-wave mixing process, which is boosted up by the Raman response in the fiber.