Generation of multiple VUV dispersive waves using a tapered gas-filled hollow-core anti-resonant fiber

Hollow-core anti-resonant (HC-AR) fibers are perhaps the best platform for ultrafast nonlinear optics based on light-gas interactions because they offer broadband guidance and low-loss guidance. The main advantage of using gases inside HC fibers is that both the dispersion and nonlinearity can be tuned by simply changing the pressure of the gas [1]. The emission of efficient dispersive wave (DW) in the deep-UV has been already observed in a uniform Ar-filled hollow-core fiber with tunability from 200 to 320 nm by changing the gas pressure and pulse energy [2]. In the quest of optimizing the nonlinear process to further blue-shift the generated DWs towards vacuum ultra-violet (VUV), here we numerically demonstrate for the first time (to the best of our knowledge) how the use of a tapered Ar-filled HC-AR fiber leads to multiple DWs in the extreme wavelength region from 143 to 280 nm.