Tuneable ultrafast ultraviolet pulses from Yb-based laser systems

Abstract

Wavelength-tuneable ultrafast laser pulses in the vacuum ultraviolet (VUV, 100-200 nm) are an important tool for next-generation ultrafast science and technology, as nearly all materials and chemical compounds exhibit strong electronic absorption resonances in this spectral region. Resonant dispersive wave (RDW) emission in gas-filled hollow-core fibres is a promising avenue to overcoming the limitations of both existing (excimer-based) laser sources and conventional nonlinear frequency-conversion methods. Microjoule-scale VUV pulses with few-femtosecond duration and near-perfect beam quality can be efficiently generated by driving RDW emission in simple gas-filled hollow capillaries. However, this has so far required a high-energy titanium-doped sapphire laser as the primary laser source. This limits the pulse repetition rate (and hence average power) and forms an important barrier to applications outside of specialised laboratories. Here, we demonstrate tuneable VUV generation using a high-power ytterbium-based laser, obtaining broadband pulses tuneable between 145 nm and 300 nm central wavelength.