We demonstrate the strengths and convenience of the Frequency-resolved optical switching (FROSt) method as a single tool to characterize a wide range of ultrashort pulses based on a high-repetition-rate Yb-laser spanning the visible (VIS) to the shortwave infrared (SWIR) spectral range.

We report the development of a phase-stable mid-IR Er:fiber laser-amplifier system operating at a 76 MHz repetition rate. A train of ultrashort mid-IR pulses is produced by a difference-frequency generation between a portion of the 1.55 µm output of an Er:fiber master oscillator and the dispersive wave of a supercontinuum driven by the second portion. This scheme yields a high-brightness offset-free mid-IR frequency comb at 2.8 µm motivating applications from nanophotonics to spectroscopy of trace gases.

recent advantages in the development of high-intensity and high-power ultrafast sources in mid-IR and LWIR spectral ranges and possible pathways towards sub-kW-class mid-IR systems will be discussed in the talk.

Time- and angle-resolved photoemission spectroscopy (TR-ARPES) is a pump-probe technique using an ultraviolet or extreme ultraviolet probe and a pump ranging from the THz to visible spectral regions. It benefits from the full range of nonlinear frequency conversion techniques developed by the ultrafast community. In this talk we discuss the growth of TR-ARPES, reflecting on the development of ultrafast laser sources and recent advances in high average power sources enabling a wide array of new capabilities to accelerate TR-ARPES discovery.

We exploit light guiding in cylindrical holes in silicon to realize the first metaoptics for extreme ultraviolet radiation. We demonstrate the concept by manufacturing and characterizing a metalens for 50 nm light, which achieves close to diffraction-limited focusing. As the technology can synthesize arbitrary phase profiles, it allows the realization of many optics currently unavailable in the extreme ultraviolet spectrum.

We demonstrate ultrashort pulse compression from 300 fs down to 17 fs at a repetition rate of 20 kHz and 160-µJ output pulse energy (3.2 W of average power) using multidimensional solitary states (MDSS) in a 1-meter hollow-core fiber (HCF) filled with N2O. Under static pressure, thermal limitations at this repetition rate annihilate the MDSS with suppression of spectral broadening. The results obtained in differential pressure configuration mitigate thermal effects and significantly increase the range of repetition rate over which MDSS can be used to compress sub-picosecond laser pulses. The ability to generate MDSS pulses, exhibiting negative dispersion, in such short HCF opens the door to a compact, economic, and efficient single-stage compression system for ytterbium lasers.