Passive mode locking of optical parametric oscillators: an efficient technique for generating sub-picosecond pulses.
We show that optical parametric generation in a nonlinear crystal with a large group velocity mismatch between the pump and nearly-degenerate signal and idler is analogous to laser amplification in the medium with a gain recovery time comparable to the walk-off time. Based on this conclusion we propose to combine an OPO with a nonlinear saturable absorber or Kerr lens to generate directly high peak power sub-picosecond pulses using pump pulses ranging from tens of picoseconds to quasi-CW. Our analytical model predicts better than 80% photon conversion efficiency and pulse lengths that are of the order of a few hundred femtoseconds. Numerical simulations confirm our predictions and show that repetitive passive mode locking is feasible with a quasi-CW pump.
Khurgin
J
J
Johns Hopkins University, Baltimore MD 21218, USA.
Melkonian
J M
JM
Godard
A
A
Lefebvre
M
M
Rosencher
E
E
D000669:Amplifiers, Electronic; D003198:Computer Simulation; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007834:Lasers; D008962:Models, Theoretical; D009991:Oscillometry / Q000295:instrumentation*