Feature Request: Calculation of Second- and Third-Order Nonlinear Optical Properties

[dyzheng]

Background

From abacusmodeling#298

Describe the solution you'd like

.

Task list only for developers

• Notice possible changes of behavior
• Explain the changes of codes in core modules of ESolver, HSolver, ElecState, Hamilt, Operator or Psi

Notice Possible Changes of Behavior (Reminder only for developers)

No response

Notice any changes of core modules (Reminder only for developers)

No response

Notice Possible Changes of Core Modules (Reminder only for developers)

No response

Additional Context

No response

Task list for Issue attackers (only for developers)

• Review and understand the proposed feature and its importance.
• Research on the existing solutions and relevant research articles/resources.
• Discuss with the team to evaluate the feasibility of implementing the feature.
• Create a design document outlining the proposed solution and implementation details.
• Get feedback from the team on the design document.
• Develop the feature following the agreed design.
• Write unit tests and integration tests for the feature.
• Update the documentation to include the new feature.
• Perform code review and address any issues.
• Merge the feature into the main branch.
• Monitor for any issues or bugs reported by users after the feature is released.
• Address any issues or bugs reported by users and continuously improve the feature.

[WHUweiqingzhou]

@jingan-181 could PYATB calculate these properties now?

[jingan-181]

1. The nonlinear optical properties currently supported by PYATB are mainly second-order types, including shift current, injection current (or circular photovoltaic effect), second harmonic generation (SHG), Berry curvature dipole, and Pockels effect. Third-order optical properties have not been covered yet.

2. The functions requested in the Feature Request: Calculation of Second- and Third-Order Nonlinear Optical Properties abacusmodeling/abacus-develop#298, third harmonic generation (THG), two-photon absorption (TPA), Stimulated Raman Scattering (SRS), and Kerr effects, are not currently available in PYATB.