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The emission of resonant radiation from temporal solitary waves—also known as dispersive wave generation—allows efficient energy transfer to far‐distant spectral domains. This coherent radiation can deliver large spectral densities at selected wavelengths once control over the individual soliton is achieved. Here, the concepts of few‐mode operation and local temperature tuning are combined for precise steering of cascaded dispersive wave generation in liquid‐core optical fibers. By exciting higher‐order TM and TE modes with femtosecond pulses at 1600 nm, the generation of two dispersive waves tunable by up to 33 nm K−1 through adjusting a selected part of the waveguide is observed. Sophisticated soliton‐driven nonlinear dynamics arising from thermally transitioning from anomalous to all‐normal dispersion with temperature changes of only a few Kelvin have been found, including soliton steering, soliton breakdown, and soliton post‐fission tuning. All experimental results are verified by nonlinear simulations and semi‐analytic phase‐matching calculations, overall providing a cost‐effective and practical toolbox for discovering unexplored states of light as well as for developing dynamically tunable broadband light sources. [ABSTRACT FROM AUTHOR]

Ultrafast laser welding is a fast, clean, and contactless technique for joining a broad range of materials. Nevertheless, this technique cannot be applied for bonding semiconductors and metals. By investigating the nonlinear propagation of picosecond laser pulses in silicon, it is elucidated how the evolution of filaments during propagation prevents the energy deposition at the semiconductor–metal interface. While the restrictions imposed by nonlinear propagation effects in semiconductors usually inhibit countless applications, the possibility to perform semiconductor–metal ultrafast laser welding is demonstrated. This technique relies on the determination and the precompensation of the nonlinear focal shift for relocating filaments and thus optimizing the energy deposition at the interface between the materials. The resulting welds show remarkable shear joining strengths (up to 2.2 MPa) compatible with applications in microelectronics. Material analyses shed light on the physical mechanisms involved during the interaction. [ABSTRACT FROM AUTHOR]