Highly transient stimulated Raman scattering in SrMoO₄ under ultrafast laser pumping with a controllable chirp

Area of Science:

• Laser Physics
• Nonlinear Optics
• Materials Science

Background:

• Stimulated Raman Scattering (SRS) is a key nonlinear optical process for generating new wavelengths.
• Strontium molybdate (SrMoO4) crystals possess unique Raman properties suitable for nonlinear applications.
• Achieving efficient, multiwavelength SRS often faces challenges like self-phase modulation (SPM).

Purpose of the Study:

• To demonstrate highly transient, multiwavelength, single-pass Raman generation in SrMoO4.
• To investigate the influence of pump pulse chirping on Raman mode excitation.
• To achieve high total Raman conversion efficiency in competition with SPM.

Main Methods:

• Utilized a 58-mm-long SrMoO4 crystal as the active medium.
• Employed 1030-nm laser pulses with energies of 40 µJ.
• Controlled pump pulse dispersive stretching (0.25–6 ps) with negative and positive chirping.

Main Results:

• Achieved a high total Raman conversion efficiency of up to 48%.
• Successfully generated four Stokes components of SRS radiation at 1066, 1134, 1177, and 1261 nm.
• Optimized pump pulse chirping for simultaneous excitation of high (888 cm⁻¹) and low (327 cm⁻¹) frequency Raman modes.

Conclusions:

• Demonstrated efficient multiwavelength SRS generation in SrMoO4 for the first time.
• Showcased the effectiveness of pump pulse chirping in optimizing SRS performance.
• Highlighted the potential of SrMoO4 crystals for advanced laser applications.