Nonlinear optical response in solids from time-dependent density-functional theory simulations.

Area of Science:

• Condensed Matter Physics
• Quantum Chemistry
• Materials Science

Background:

• Accurate computation of nonlinear optical properties is crucial for understanding light-matter interactions in solids.
• Existing methods for calculating nonlinear susceptibilities often rely on perturbative approaches, limiting their applicability to strong fields or complex electronic structures.

Purpose of the Study:

• To introduce a new, non-perturbative method for calculating nonlinear susceptibilities of periodic solids.
• To dynamically couple the time-dependent Schrödinger equation with external electromagnetic fields for accurate electronic response calculation.

Main Methods:

• The study employs a time-dependent Schrödinger equation approach, dynamically coupled to an external electromagnetic field.
• Electronic response and polarization currents are computed in the frequency domain.
• Higher-order nonlinear susceptibilities are calculated non-perturbatively.

Main Results:

• The presented method successfully computes nonlinear susceptibilities for periodic solids.
• Third harmonic generation in silicon and carbon diamond were accurately simulated as illustrative examples.
• The non-perturbative nature allows for calculations beyond weak field limits.

Conclusions:

• The developed method offers a robust and accurate way to compute nonlinear optical properties of materials.
• This approach provides a valuable tool for investigating light-matter interactions and designing novel optical materials.