A Thermal Modeling Toolkit for Continuous-Wave Gaussian Second-Harmonic Generation in KTP Crystal

TL;DR

The paper tackles thermal management challenges in continuous-wave Gaussian second-harmonic generation (SHG) within potassium titanyl phosphate (KTP) by introducing an open-source finite-difference toolkit that solves the transient and steady-state heat equation with temperature-dependent conductivity and Robin boundary conditions. It provides a structured Fortran-based implementation that outputs spatiotemporal temperature fields $T(r,z,t)$ under a Gaussian heat source $\exp(-2r^2/\omega_0^2)\exp(-\alpha z)$, along with detailed geometric and boundary modeling for reproducible SHG analyses. The authors consolidate prior analytical and numerical studies into a versioned repository, including reference runs that reproduce published CW Gaussian KTP temperature distributions, and archive the release for long-term access via Zenodo. They also outline a clear roadmap toward pulsed heating, additional crystals, and post-processing hooks, positioning the toolkit as a reproducible baseline for benchmarking thermally coupled SHG and related heat-conduction problems.

Abstract

We release an open-source finite-difference toolkit for computing temperature fields in continuous-wave (CW) second-harmonic generation (SHG) using potassium titanyl phosphate (KTP) crystals under Gaussian end-pumping. The toolkit includes modules for geometry and material definitions, boundary and cooling models, and transient and steady-state finite-difference solvers. Users provide beam and crystal parameters along with cooling profiles, and the solver returns spatiotemporal temperature fields with radial and axial profiles as exportable datasets. This implementation consolidates previous work into a single versioned repository with reproducible pipelines and parameterized scenario sweeps covering temperature-dependent versus constant conductivity, convection with or without radiation, and heat-transfer coefficients from $6.5$ to $2.0 \times 10^{4}$~W~m$^{-2}$~K$^{-1}$. The compiled Fortran kernels include built-in benchmark reporting. Validation is performed by reproducing published temperature distributions and trends for KTP under Gaussian CW pumping. The code is available as an open-source GitHub repository and is released under the MIT license as version v1.0.0, with an archived release on Zenodo identified by DOI 10.5281/zenodo.17266421 for citation and long-term access.