2.3-cycle mid-infrared pulses from hybrid thin-plate post-compression at 7 W average power

Output pulses of a 100 kHz mid-infrared OPCPA system are post-compressed from 4.7 cycles down to 2.3 cycles by using a combination of a dielectric and a semiconductor crystal in a hybrid thin plate setup. Efficient spectral broadening is demonstrated with 11 W average input power. After compression the output power reached 6.8 W with exceptional CEP and energy stability for a several hours. The post-compressed pulses were carefully characterized in both temporal and spatial domains, resulting in 2.3-cycle temporal duration at 3.1 μm central wavelength with a temporal Strehl ratio of 0.73 and a spatial Strehl ratio of 0.97. Thermal limitations due to multiphoton absorption of semiconductors present at this power level are explored by temperature measurements, which are supported by detailed numerical simulations. Upscaling for higher average powers was also investigated.