Computational Investigation of Second Harmonic Generation in KTP Crystals Using COMSOL

Abstract

This study presents a COMSOL Multiphysics-based finite-element workflow for steady-state modeling of second harmonic generation (SHG) in potassium titanyl phosphate. The electromagnetic fields at the fundamental frequency 𝜔 and the second-harmonic frequency 2𝜔 are solved in the frequency domain with explicit nonlinear polarization source terms, and the resulting photon flux trends are benchmarked against the standard depletion-included slowly varying envelope approximation under an idealized phase-matched condition (Δk ~ 0). Two pump wavelengths (1064 nm and 808 nm) and their corresponding SHG wavelengths (532 nm and 404 nm) are investigated, together with parametric variations of input intensity and an effective nonlinear coefficient used in the model. The results provide spatial field maps and photon flux evolution in a reproducible finite-element method setup; reported high conversion levels should be interpreted as upper-bound trends within the simplified, lossless benchmark assumptions rather than direct bulk experimental performance predictions. The present work can serve as a practical starting point for later extensions toward tensor-resolved, dispersion-aware, and fully three-dimensional SHG models.

Received: 9 December 2025 | Revised: 28 April 2026 | Accepted: 11 June 2026

Conflicts of Interest

The authors declare that they have no conflicts of interest to this work.

Data Availability Statement

The data that support the findings of this study are available within the article.

Author Contribution Statement

Nabeel Ahmed: Conceptualization, Methodology, Software, Formal analysis, Resources, Data curation, Writing – original draft, Writing – review & editing, Visualization. Muddasir Naeem: Validation, Formal analysis, Resources, Data curation, Writing – original draft, Writing – review & editing, Visualization, Supervision. Tayyab Imran: Conceptualization, Methodology, Validation, Investigation, Resources, Data curation, Writing – original draft, Writing – review & editing, Supervision, Project administration.