Multifrequency parametric infrared Raman generation in KGd(WO(4))(2) crystal with biharmonic ultrashort-pulse pumping

Area of Science:

• Nonlinear Optics
• Laser Physics
• Materials Science

Background:

• Stimulated Raman scattering (SRS) is a key nonlinear optical process.
• KGd(WO4)2 (potassium gadolinium tungstate) is a promising crystal for nonlinear applications.
• Parametric Raman generation offers a route to multifrequency light sources.

Purpose of the Study:

• Investigate multifrequency parametric Raman generation in KGd(WO4)2.
• Determine the effect of pulse duration and chirp on Raman generation efficiency.
• Understand the role of self-phase modulation in suppressing SRS.

Main Methods:

• Utilized a dual-wavelength Ti:sapphire laser system for pumping.
• Employed femtosecond and picosecond (ps) chirped laser pulses.
• Analyzed the generated Stokes and anti-Stokes components.

Main Results:

• Low efficiency of Raman generation observed with femtosecond pump pulses.
• Self-phase modulation was identified as the cause of efficiency suppression.
• Generation of four Stokes and one anti-Stokes component achieved using 2-ps chirped pulses.

Conclusions:

• Pulse chirp and duration are critical parameters for efficient parametric Raman generation.
• Self-phase modulation significantly impacts SRS, necessitating careful pulse control.
• KGd(WO4)2 crystals are suitable for generating multiple Raman frequencies with optimized laser pulses.