High harmonics generated in dense nonlinear media, such as solids, are strongly absorbed by the material itself. I will show how a suitably nano-patterned crystal greatly overcomes the absorption limit of bulk, paving the way for bright on-chip short-wavelength sources.
An Yb:thin-disk laser delivering 615 fs pulses with 17 mJ energy at 3 kHz is harnessed towards generation of single-cycle multi-THz transients with few hundred MV/cm field strength via chirped-pulse difference frequency mixing in large-aperture GaSe crystals.