Energetic picosecond 10.2-μm pulses generated in a BGGSe crystal for nonlinear seeding of terawatt-class CO2 amplifiers
Ya-Po Yang, Jheng-Yu Lee, Jyhpyng Wang
Optics Express
We demonstrate what we believe to be a new approach to energetic picosecond
10.2-μm pulse generation based on nonlinear mixing of subnanosecond single-frequency 1338-
nm pulses and broadband 1540-nm chirped pulses in a BGGSe crystal followed by a grating
compressor for the purpose of seeding high-power CO2 amplifiers. The energy of the 10.2-μm
pulses exceeding 60 μJ with 3.4%-rms fluctuation can be routinely obtained. Single-shot pulse
duration measurement, performed by Kerr polarization rotation time-resolved by a streak camera,
together with the pulse spectrum, indicates the pulse width is between 2.7-3 ps. Numerical
calculations show that power broadening and dynamic gain saturation with Rabi-flopping can
be induced with such an intense seed in a multi-atmospheric CO2 amplifier. These nonlinear
effects greatly suppresses pulse splitting due to the comb-like spectrum of the CO2 molecule. A
peak power exceeding 1 TW is expected after multipass of amplification while maintaining an
appropriate high intensity by controlling the beam size along the path.
Institute of Atomic and Molecular Sciences Academia Sinica
