Fig. 1. Crystal and laser pump configurations showing the decomposition of the pump and Raman scattering into respective ordinary (o) and extraordinary (e) components. The optic axis (OA) is in the x–z plane, and the Raman k vector k_R can be in any direction.

Fig. 2. The Raman cross-section function for a specific crystal cut orientation (quantified by the OA angle θ) is defined for any direction in the 3D space for each Raman polarization using two coordinates, the azimuthal angle, , and the internal angle, α.

Fig. 3. The normalized Raman scattering cross-section function (maximum value is 1) in three dimensions calculated for the o-polarization component as a function of the optic axis (θ) orientation.

Fig. 4. The normalized Raman scattering cross-section function (maximum value is 1) in three dimensions calculated for the e-polarization component as a function of the optic axis (θ) orientation.

Fig. 5. Example case of the estimation of the gain factors assuming a source point at the middle of the plate for the (a) o-polarization and (b) e-polarization components as a function of the azimuthal angle () and the ray tilt angle (α) for a square crystal plate with the OA angle (θ) at 60° and pump polarization in the 45° diagonal direction.

Fig. 6. Considerations for modeling the gain factor assuming square optics where (a) shows the different photon propagation paths involving total internal reflections and (b) the signal arriving at any point in the side surfaces of the plate is considered a superposition of all rays arriving at this point that were generated in different parts of the crystal volume.

Fig. 7. TSRS fluence distribution along the (a) x-axis and (b) y-axis surfaces for THG crystal configuration (depicted in the inset, beam propagating into the page) under various pump pulse energy levels.

Fig. 8. TSRS fluence distribution along the crystal side surfaces for wave-plate crystal configuration (depicted in the inset, beam propagating into the page) under various pump pulse energy levels with the optic axis tilted by (a) 10° and (b) 90°. The maximum fluence is along the diagonal direction orthogonal to the direction of the OA.

Fig. 9. The maximum TSRS fluence as a function of the OA tilt angle for the case of a wave-plate crystal configuration (depicted in the inset, beam propagating into the page) for DKDP.

Fig. 10. TSRS fluence distribution (a) along the x side surface for an alternate DKDP wave-plate configuration (depicted in the inset, beam propagating into page) for various OA tilt angles assuming an intensity of 2 GW/cm² and (b) along the x and y sides for the case of OA tilt angle of 90°.