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This platform allows distribution of the nonlinear interaction over large distances and multiple beam foci. The principles, experimental implementations, and applications of nonlinear optics in multipass cells are reviewed. Nonlinear optics experiments in multipass cells bear some similarities with the work done in optical fibers over several decades, while allowing straightforward energy scaling potential, and unlocking engineering possibilities through the design of the cell mirrors, geometry, and nonlinear medium. However, other nonlinear phenomena and functions are being increasingly investigated, such as supercontinuum generation, spectral compression, or Raman scattering. Most of the research so far has been focused on temporal compression based on self‐phase modulation, with excellent performances especially in terms of energy scaling and throughput. Embedding a nonlinear medium in a multipass cell allows for a distribution of the nonlinearity over large interaction distances, while the beam goes through multiple foci, conferring on the beam a robustness with respect to spatio‐spectral coupling effects. The fundamental principles and experimental implementations of multipass cells used as a platform for nonlinear optics are reviewed. Due to the method’s simplicity, compactness, and scalability, it is highly attractive for turning a picosecond laser into an ultrafast light source that generates pulses of only a few tens of femtoseconds duration.
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Furthermore, we have measured state-of-the-art spectral-spatial homogeneity and good beam quality of M 2 = 1.2 up to a spectral broadening factor of 30. With only 0.19% rms pulse-to-pulse energy fluctuations, the technique exhibits excellent stability. We use a burst-mode Yb:YAG laser emitting pulses with 80 MW peak power that are enhanced to more than 1 GW after postcompression. Moreover, our approach efficiently suppresses adverse features of single-pass bulk spectral broadening. Their combination leads to significantly higher spectral broadening factors in bulk material than what has been reported from either method alone. Our approach is based on the hybridization of the multiplate continuum and the multipass cell spectral broadening techniques. Here, we present a very compact and highly robust method to compress 1.24 ps pulses to 39 fs by means of only a single spectral broadening stage which neither requires vacuum parts nor custom-made optics. Due to the method's simplicity, compactness and scalability, it is highly attractive for turning a high-power picosecond laser into an ultrafast light source that generates pulses of only a few tens of femtoseconds duration.Īs ultrafast laser technology advances towards ever higher peak and average powers, generating sub-50 fs pulses from laser architectures that exhibit best power-scaling capabilities remains a major challenge. Furthermore, we have measured state-of-the-art spectral-spatial homogeneity and good beam quality of M$^2 = 1.2$ up to a spectral broadening factor of 30. With only 0.19 % rms pulse-to-pulse energy fluctuations, the technique exhibits excellent stability. We use a burst mode Yb:YAG laser emitting pulses with 80 MW peak power that are enhanced to more than 1 GW after post-compression. Our approach is based on the hybridization of the multi-plate continuum and the multi-pass cell spectral broadening techniques. As Ultrafast laser technology advances towards ever higher peak and average powers, generating sub-50 fs pulses from laser architectures that exhibit best power-scaling capabilities remains a major challenge.