Ultra-low threshold deep ultraviolet generation in a hollow-core fiber.

Tunable ultrashort pulses in the ultraviolet spectral region are in great demand for a wide range of applications, including spectroscopy and pump-probe experiments. While laser sources capable of producing such pulses exist, they are typically very complex. Notably, resonant dispersive-wave (RDW) emission has emerged as a simple technique for generating such pulses.

Stack, seal, evacuate, draw: a method for drawing hollow-core fiber stacks under positive and negative pressure.

The two-stage stack and draw technique is an established method for fabricating microstructured fibers, including hollow-core fibers. A stack of glass elements of around a meter in length and centimeters in outer diameter forms the first stage preform, which is drawn into millimeter scale canes. The second stage preform is one of the canes, which is drawn, under active pressure, into microscopic fiber.