Generation of background-free pulses at 1064 nm accurately synchronized with femtosecond laser pulses at 794 nm

This paper reports on generation of background-free pulses at 1064 nm accurately synchronized with femtosecond pulses at 794 nm, by the use of a continuous-wave He-Ne laser seeded non-collinear optical parametric amplification (NOPA) pumped by frequency-doubled Ti:sapphire femtosecond laser at 396nm. Experimental results showed that the 1064 nm light pulses can be used as the pump seed for optical parametric chirped pulse amplification to realize an all-optical synchronization between pump and signal beams. Background-free pulses at 1064 nm could also be generated by using a NOPA with continuous-wave seed from the intracavity 632.8 nm light of an appropriate He-Ne cavity. The spectral and spatial chirp properties of the idler pulses were quite similar in both cases according to our measurements. The generated idler pulses in the intracavity seed case have single pulse energy 10 times that of the external cavity case.