Liquid sheets and heterostructures for FEL and laser applications

Liquid sheet jets have rapidly grown in popularity for FEL and high-power laser applications as they generate liquid targets that are optically flat, vacuum stable, constantly refreshing, and are able to reach sub-micron optical path lengths required for transmission measurements across the photon spectrum. This presentation will be an overview of microfluidic liquid flatjet technologies developed at SLAC/LCLS for use at FELs and will also include updates on new liquid manipulation techniques currently under development. We recently demonstrated the generation of a new class of sheet jet comprised of two stacked liquids (a “liquid heterostructure”) by colliding two jets of one liquid onto opposite sides of a third jet of another liquid. The resulting structure is a layered sheet jet where a thin sheet of one liquid is completely enveloped by a larger sheet of a different liquid. If the component liquids are miscible, the thin component layers result in fast diffusive mixing on sub-millisecond time scales. If the component liquids are immiscible, the resulting structure contains well-defined, large-area liquid-liquid interfaces with a minimized bulk liquid background.