"Generation of 10 to 50 fs pulses tunable through all of the visible and the NIR"E. Riedle, M. Beutter, S. Lochbrunner, J. Piel, S. Schenkl, S. Spörlein, W. Zinth
Appl. Phys. B 71, 457 - 465 (2000)
Noncollinearly phase matched optical parametric amplifiers (NOPAs) pumped by theblue light of a frequency doubled Ti:sapphire regenerative amplifier are a convenientsource of continuously tunable ultrashort pulses in the visible and near infrared forspectroscopic experiments. We present the underlying principles, report recentimprovements and describe the experiences gained from the routine use of anumber of NOPAs in our labs. We find that the setup can easily be optimized for thegiven experimental requirements. Typical output pulse energies in the visible are 5 to10 µJ and a few µJ in the NIR from 200 µJ regenerative amplifier pulses at 800 nm.From 460 to 700 nm pulse lengths between 10 and 20 fs are routinely achieved,while the length increases monotonically from about 20 fs at 900 nm to just below 50fs at 1600 nm. In all cases this corresponds to a dramatic shortening compared tothe length of the pump pulses of around 100 fs. First results are shown that the 700to 900 nm region can be accessed with sub-50 fs pulse lengths by use of anintermediate white light generator in a two-stage setup.
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