Numerical investigations of parametric transfer in synchronously pumped optical parametric oscillators for indirect mid-infrared pulse shaping

Experimental investigation of parametric transfer in synchronously pumped optical parametric oscillators

“…We next consider the effect of the pump depletion on the transfer fidelity. According to our numerical investigations [20], higher pump depletion without going to the back-conversion regime results in an improvement of the transfer fidelity, except in the presence of GDD. The improvement of transfer fidelity with pump depletion is due to an effective temporal broadening of the signal pulse relative to the pump when considering a single pass DFG process.…”

“…This equation is analogous to the expression for Z given in Ref. [20], comparing the overlap of the pump and idler spectrograms. As with Z, the spectral transfer fidelity z, ranges between zero and unity, where zero corresponds to perfect overlap and unity indicates no overlap.…”

“…From our numerical investigations [20], we identified parameters leading to a high fidelity parametric transfer, such as, placing an optical band-pass filter in the resonator, working at high pump depletion and low signal amplification, tuning the cavity length to compensate for the pump-signal TWO, and selecting the appropriate crystal length or idler wavelength to minimise pump-idler TWO. We therefore complied with these requirements by providing the cavity with an etalon whilst maintaining a low loss cavity by using mirrors that are highly reflecting at the signal wavelengths, working with a pump power at three times above threshold to achieve significant pump depletion whilst avoiding the back-conversion regime, and choosing the idler wavelength to be 3440 nm.…”

“…In this paper, we experimentally investigate the parameters that affect parametric transfer in a SPOPO, based on the findings from the previous theoretical work [20]. To the best of our knowledge, this is the first experimental study of parametric transfer in a SPOPO and by collective consideration of all investigated factors we demonstrate high fidelity transfer to the MIR idler pulse.…”

“…Following this demonstration of the potential for this adaptive MIR pulse shaping technique, we progressed to numerical studies of the fidelity of transfer, firstly in the simple single pass DFG process [19] and then to the somewhat more complicated case of the SPOPO [20]. The effects of temporal walk-off (TWO), group delay dispersion (GDD), signal bandwidth, signal amplification and pump depletion were considered.…”