Efficient phase-matching for difference frequency generation with pump of Bessel laser beams

Area of Science:

• Nonlinear Optics
• Quantum Optics
• Laser Physics

Background:

• Difference frequency generation (DFG) is crucial for generating new frequencies.
• Traditional phase matching methods often impose strict constraints on crystals and pump sources.
• Bessel beams offer unique propagation characteristics beneficial for nonlinear optical processes.

Purpose of the Study:

• To propose and analyze a novel phase matching scheme for DFG using Bessel-type pump beams.
• To investigate the feasibility of achieving phase matching in a conical region around the laser path.
• To explore the potential for relaxed phase matching conditions in various nonlinear optical materials.

Main Methods:

• Theoretical proposal of a DFG geometry utilizing Bessel-type pump beams.
• Development of a semi-analytical model for calculating energy conversion efficiency.
• Consideration of an experimental scenario involving 1.5 THz generation in bulk GaAs pumped by ~2 μm lasers.

Main Results:

• Phase matching can be achieved by controlling the Bessel beam profile, creating a conical phase-matching region.
• The semi-analytical model provides insights into energy conversion characteristics.
• The proposed configuration demonstrates potential for broader applicability across different nonlinear crystals and pump wavelengths.

Conclusions:

• The Bessel beam-based phase matching technique offers a flexible alternative to conventional methods.
• This approach could significantly reduce limitations in designing DFG systems.
• The findings suggest a pathway towards more versatile terahertz (THz) generation and other nonlinear optical applications.