Multi-pass cells: A disruptive technology in the field of ultrafast optics
Multi-pass cells (MPCs) have been instrumental in enabling the generation of high average power ultrashort laser pulses with bandwidths much beyond what can be achieved by common laser gain media. MPCs typically depend on self-phase modulation (SPM) to expand the available wavelength range of a laser pulse. However, a large amount of SPM on its own can cause the beam’s spatial profile to worsen, aside from adding unwanted higher-order spectral phase that could be present in the broadened spectrum. In this talk, I will discuss how MPCs have been used to avoid these problems [Optica 9, 197 (2022)], and how MPCs could be scaled further towards higher pulse compression ratios through cascading [J. Opt. Soc. Am. B 39, 1694 (2022)]. I will also present recent experimental results, showing how MPCs have made new parameter regimes accessible, and different opportunities with MPCs that could be reached in the near future.