Terahertz-induced cascaded interactions between spectra offset by large frequencies

Area of Science:

• Nonlinear Optics
• Terahertz (THz) Photonics
• Materials Science

Background:

• Cascaded second-order nonlinear processes are crucial for frequency conversion.
• Efficient generation of terahertz radiation is vital for various scientific applications.
• Previous methods required specific frequency matching between optical spectra.

Purpose of the Study:

• To explore a novel system for generating terahertz radiation.
• To investigate the strong coupling of optical spectra with disparate center frequencies.
• To overcome limitations of previous cascaded parametric amplification techniques.

Main Methods:

• Utilizing highly phase-matched, cascaded second-order nonlinear processes driven by terahertz radiation.
• Employing a model for nonlinear coupled interaction of terahertz and optical waves.
• Accounting for second and third-order nonlinearities, dispersion, and absorption.

Main Results:

• Demonstrated strong coupling of optical spectra with frequency separations over ten times the terahertz frequency.
• Predicted percent-level conversion efficiencies and millijoule-level pulse energies for terahertz generation.
• Estimated laser-induced damage and outlined mitigation strategies.

Conclusions:

• The proposed system offers a flexible and efficient route for terahertz radiation generation.
• Cryogenically-cooled periodically poled lithium niobate is a promising material for this application.
• Understanding nonlinear dynamics is key to optimizing terahertz generation and mitigating damage.