Developed a major enhancement for the FEniCS/dolfinx repository by implementing a Helmholtz plane-wave solver in complex mode with mixed Dirichlet and Neumann boundary conditions. The work focused on consolidating code paths for real and complex solutions within demo_helmholtz.py, improving maintainability and reducing duplication. Using Python and leveraging expertise in the Finite Element Method and scientific computing, the developer aligned the demo configuration with established acoustic scattering literature. This update enabled more realistic demonstrations and facilitated validation and teaching. The contribution deepened the educational value of the demo while ensuring reproducibility and clarity for users exploring numerical methods.