Generation of micro-J pulses in the deep UV at MHz repetition rates

TL;DR

This paper demonstrates the generation of tunable deep-UV ultrashort pulses at MHz repetition rates using gas-filled hollow-core photonic crystal fibers, enabling new possibilities in UV science and technology.

Contribution

It introduces a novel method for producing high-repetition-rate, tunable deep-UV pulses via dispersive wave emission in gas-filled photonic fibers, achieving higher average powers than previous sources.

Findings

Achieved 205 nm pulses at 100 kHz with 1.05 μJ energy.

Generated 275 nm pulses at 1.92 MHz with 0.54 μJ energy.

Demonstrated tunability by changing gas species and pressure.

Abstract

Although ultraviolet (UV) light is important in many areas of science and technology, there are very few if any lasers capable of delivering wavelength-tunable ultrashort UV pulses at MHz repetition rates. Here we report the generation of deep-UV laser pulses at MHz repetition rates and \mu J-energies by means of dispersive wave (DW) emission from self-compressed solitons in gas-filled single-ring hollow-core photonic crystal fiber (SR-PCF). Pulses from an ytterbium fiber laser (~300 fs) are first compressed to ~25 fs in a SR-PCF-based nonlinear compression stage, and subsequently used to pump a second SR-PCF stage for broadband DW generation in the deep UV. The UV wavelength is tunable by selecting the gas species and the pressure. At 100 kHz repetition rate, a pulse energy of 1.05 \mu J was obtained at 205 nm (average power 0.1 W), and at 1.92 MHz, a pulse energy of 0.54 \mu J was obtained at 275 nm (average power 1.03 W).