Performance of MgO:PPLN, KTA, and KNbO3 for mid-wave infrared broadband parametric amplification at high average power.

ABSTRACT

The performance of potassium niobate (KNbO3), MgO-doped periodically poled lithium niobate (MgOPPLN), and potassium titanyl arsenate (KTA) were experimentally compared for broadband mid-wave infrared parametric amplification at a high repetition rate. The seed pulses, with an energy of 6.5 µJ, were amplified using 410 µJ pump energy at 1064 nm to a maximum pulse energy of 28.9 µJ at 3 µm wavelength and at a 160 kHz repetition rate in MgOPPLN while supporting a transform limited duration of 73 fs. The high average powers of the interacting beams used in this study revealed average power-induced processes that limit the scaling of optical parametric amplification in MgOPPLN; the pump peak intensity was limited to 3.8 GW/cm² due to nonpermanent beam reshaping, whereas in KNbO3 an absorption-induced temperature gradient in the crystal led to permanent internal distortions in the crystal structure when operated above a pump peak intensity of 14.4 GW/cm².