Increased wavelength options in the visible and ultraviolet for Raman lasers operating on dual Raman modes

Area of Science:

• Optics and Photonics
• Laser Physics

Background:

• Raman lasers offer tunable wavelength generation.
• Dual Raman modes with similar gain coefficients present unique opportunities for wavelength expansion.

Purpose of the Study:

• To investigate the simultaneous generation of multiple Stokes orders from a dual Raman mode system.
• To explore the potential for increased wavelength options through intracavity nonlinear frequency mixing.

Main Methods:

• Utilized an external-cavity potassium gadolinium tungstate (KGW:GdVO4) Raman laser pumped at 532 nm.
• Employed appropriate orientation of the Raman crystal to excite two Raman modes.
• Performed intracavity nonlinear sum frequency and difference frequency mixing in BBO (beta-barium borate).

Main Results:

• Observed simultaneous generation of two sets of Stokes orders.
• Generated wavelengths corresponding to the sums of the two Raman modes.
• Achieved up to 14 visible Stokes lines (555-675 nm) and demonstrated 30 output wavelength options (271-321 nm) using sum frequency mixing.
• Presented a theoretical analysis for predicting wavelength options in dual Raman mode systems.

Conclusions:

• Dual Raman mode systems significantly increase achievable wavelength options from Raman lasers.
• The demonstrated technique enhances wavelength selectivity for various laser applications.
• Theoretical analysis provides a predictive tool for optimizing dual Raman mode laser designs.