Broadband sum-frequency generation of spectrally incoherent pulses

We study and demonstrate the nonlinear frequency conversion of broadband optical pulses from 1053 nm to 351 nm using sum-frequency generation with a narrowband pulse at 526.5 nm. The combination of angular dispersion and noncollinearity cancels out the wave-vector mismatch and its frequency derivative, yielding an order-of-magnitude increase in spectral acceptance compared to conventional tripling. This scheme can support the nonlinear frequency conversion of broadband spectrally incoherent nanosecond pulses generated by high-energy lasers and optical parametric amplifiers to mitigate laser-plasma instabilities occurring during interaction with a target. The experimental results obtained with KDP crystals are in excellent agreement with modeling, demonstrating the generation of spectrally incoherent pulses with a bandwidth larger than 10 THz at 351 nm. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

Researchers demonstrated a method for nonlinear frequency conversion using a narrowband pulse, which can generate a broader spectrum in spectrally incoherent nanosecond pulses. Experimental results show that this scheme can effectively mitigate laser-plasma instabilities occurring during interaction between high-energy lasers and targets.