Wave Optics Module

Full-Wave Electromagnetics Analyses

The Wave Optics Module enables you to quickly and easily set up a model in 2D, 2D axisymmetric, and 3D domains. Both fundamental and advanced boundary conditions are included for your analyses.

The workflow is straightforward and can in general be described by the following steps: create or import the geometry, select materials, select a suitable Wave Optics interface, define boundary and initial conditions, define the mesh, select a solver, and visualize the results. All of these steps are accessed from the COMSOL Multiphysics^® environment. Meshing and solver settings are automatic with options for manual editing.

The functionality of the Wave Optics Module covers simulation of electromagnetic fields and waves based on Maxwell’s equations together with material laws for propagation in various media. The modeling capabilities are accessed via built-in user interfaces, which allow you to analyze wave phenomena in optics and photonic devices.

The Wave Optics Module enables modeling in the frequency and time domain, including eigenfrequency, and mode analysis.

Optical Materials

Use materials from the built-in optical materials database or define your own. You can specify the relative permittivity or refractive index as well as include more advanced material properties such as Debye, Drude–Lorentz, and Sellmeier dispersion. Materials can be anisotropic as well as functionally graded.

Take full control over your simulation by modifying material definitions, the governing Maxwell's equations, or boundary conditions directly within the software. This flexibility enables you to create a variety of user-defined materials, including metamaterials, with engineered properties, and gyromagnetic and chiral materials.

Data Visualization and Extraction

The results are presented using, for example, plots of electric and magnetic fields, reflectance, transmittance, diffraction efficiency, S-parameters, power flow, and dissipation. You can also create visualizations of nonstandard expressions in terms of physical quantities that you can define freely. This makes it possible to gain deeper insight by enabling examination of virtually every aspect of the results.

Nonlinear Optics

The Wave Optics Module provides several features for simulating nonlinear optics in both the time and frequency domains. In the frequency domain, you can have field-dependent material properties for phenomena such as self-focusing, or you can couple multiple frequency-domain analyses together to model mixing between two or more waves at different frequencies like sum or difference frequency generation. By incorporating nonlinear polarization terms, this approach allows for nonlinear simulations using continuous wave (CW) lasers or other quasi-steady-state phenomena. There is similar flexibility in the time domain, where polarization or remnant electric displacement terms can be modified to enable more advanced modeling scenarios like ultrafast phenomena.

Boundary Conditions

Electromagnetic wave modeling requires highly specialized boundary conditions, including the capability of modeling unbounded domains as well as periodic structures such as metamaterials. For example, modeling a periodic metamaterial requires periodic ports that can handle arbitrary angles of incidence and diffraction orders. For general modeling of waveguides and optical fibers, numerical mode-matched ports are required to properly feed waveguides with incoming light.

Important Boundary Conditions in the Wave Optics Module

• Perfect electric conductor (PEC)
• Impedance (finite conductivity)
• Transition (thin lossy conductive sheet)
• Periodic ports with arbitrary diffraction orders
• Floquet, or Bloch, periodicity
• Scattering (absorbing) boundaries
• Ports
  • Analytical shapes
  • Numeric (mode matched)

Multiphysics Effects in Optical Devices

The Wave Optics Module can be combined with any other module to simulate multiphysics phenomena, all of which seamlessly integrate with the core COMSOL Multiphysics^® software platform. This means that your modeling workflow remains the same, regardless of the application area or physics you are modeling.

You may want to examine the effects that mechanical deformation has on your device's performance, including stress-optical effects. Similarly, you can examine how heat transfer, thermal stress, and thermal dissipation affect a device.

Additionally, you can simulate how various physical phenomena can be used for modulation purposes, such as acousto-optical, electro-optical, and magneto-optical effects.

By combining with a mass transport simulation, you can compute realistic refractive index profiles with anisotropic diffusion coefficients and use the results in an electromagnetics analysis.

Periodic Structures

Periodic structures are fundamental to many engineered electromagnetic structures being developed for applications such as polarimetric and subwavelength imaging and diffractive optics. In the Wave Optics Module, you can model these structures, including their high-order diffraction modes, with Floquet periodic conditions and varying diffraction orders. Using these features, you can accurately design elements for metasurfaces and other flat optics.

Scattering

Accurate scattering models of gold nanoparticles, for example, can be easily accomplished using a scattered field formulation. In this approach, the Wave Optics Module provides you with the choice of an incident plane wave, a Gaussian beam (both with and without the paraxial approximation), or a user-defined excitation and then solves for the scattered field induced by the chosen excitation. The simulation domain can approximate an infinite space by absorbing the outgoing radiation using perfectly matched layers (PMLs), which simultaneously absorb radiation for a range of frequencies and angles of incidence. Using a near-to-far field transformation, the far-field radiation of the scatterer can be analyzed.