Raman wavelength conversion in a multipass cell

Abstract

Positively chirped femtosecond pulses at 1030 nm are wavelength-converted using spontaneous and stimulated Raman scattering in a KGW crystal inserted inside a multipass cell. Recirculation in the cell and the Raman material allows both a high conversion efficiency and good spatial beam quality for the generated Stokes beams. The converted pulses can be compressed to subpicosecond duration. Multipass cells could be an appealing alternative to other Raman shifter implementations in terms of thermal effects, control of the Raman cascade, and overall output beam quality.

Synthesis of Adjacent Stokes Spectra in a Two-Stage Transient Stimulated Raman Chirped-Pulse Amplifier

“…As a result, the conversion efficiency was lower compared to the amplification of a single Stokes component in two successive TSRCPA stages [13]. Indeed, additional amplification stages or a multi-pass cell (MPC) can be used to further improve conversion efficiency [19].…”

Nonlinear Optics in Multipass Cells

“…[78][79][80] This idea was revisited recently to show that it is possible to transfer the energy of an input chirped femtosecond pulse to a long wavelength-shifted pulse through Raman stimulated scattering in a solid medium located in an MPC. [50] Here the use of an MPC brings a number of possible advantages compared to previous experiments done in single pass geometries through the material. It is possible to use higher peak powers, because the Raman material thickness is decreased in the multipass geometry.…”

“…This approach represents a good tradeoff whenever one wants to retain an accurate description of spatio‐temporal couplings, for example, to investigate a novel highly nonlinear MPC configuration. If the space‐time structure of the beam is expected to be heavily influenced by the nonlinearity, for instance in MPCs where a Raman Stokes wave generation takes place, [ 50 ] this approach is also necessary.…”