Efficient and compact source of tuneable ultrafast deep ultraviolet laser pulses at 50 kHz repetition rate

Deep ultraviolet (DUV) laser pulses with tuneable wavelength and very short duration are a key enabling technology for next-generation technology and ultrafast science. Their generation has been the subject of extensive experimental effort, but no technique demonstrated thus far has been able to meet all requirements in one light source. Here we demonstrate a bright, efficient, and compact source of tuneable deep ultraviolet ultrafast laser pulses based on resonant dispersive wave emission in hollow capillary fibre. In a total footprint of only 120 x 75 cm, including the ytterbium-based drive laser, we generate pulses between 208 nm and 363 nm at 50 kHz repetition rate with a total efficiency of up to 3.6%. Down-scaling of the DUV generation reduces the required energy sufficiently to enable the generation of two-colour few-femtosecond DUV pulses.