Distributed source model for the full-wave electromagnetic simulation of nonlinear terahertz generation.

Area of Science:

• Nonlinear optics
• Computational electromagnetics
• Terahertz science

Background:

• Optical rectification in nonlinear crystals is a key method for terahertz (THz) generation.
• Accurate modeling of THz radiation is crucial for advanced applications like near-field microscopy.
• Existing simulation methods may not fully capture the complex interactions of THz beams.

Purpose of the Study:

• To develop a novel modeling approach for THz generation via optical rectification.
• To enable predictive simulations of THz near-field interactions with micro-structured samples.
• To validate the proposed model through experimental measurements.

Main Methods:

• Discretized equivalent current sources are used to model THz generation within the nonlinear crystal.
• The equivalent sources are computed based on a modeled near-infrared pump beam.
• A full-wave electromagnetic simulation tool is employed to simulate the generated THz radiation.

Main Results:

• The distributed source model provides an appropriate excitation for full-wave simulations.
• Numerical results were validated against experimental measurements using square apertures.
• The model accurately predicts near-field interactions of THz beams.

Conclusions:

• The proposed equivalent current source model effectively simulates THz generation.
• This approach facilitates predictive modeling for THz near-field microscopy.
• The methodology is adaptable to other nonlinear optical processes and simulation tools.