Fig. 3: Schematic experimental setup for intrapulse difference frequency generation.
From: Watt-scale super-octave mid-infrared intrapulse difference frequency generation
a The experimental setup for intrapulse DFG comprises a table-top thulium-doped fiber chirped-pulse amplification system (Tm:FCPA), an antiresonant hollow-core-fiber-based nonlinear self-compression stage and a separate chamber filled with 1 bar of helium gas for the mitigation of thermal blooming35, which enables efficient intrapulse difference frequency generation. b Beam focus with a 380 µm 1/e² width, which produces a peak intensity of 1.59 TW/cm² at the GaSe crystal for intrapulse DFG. c Thermal camera image of the GaSe crystal, while illuminating with an 80 W-average-power laser for several minutes
