Wave Optics Module
Wave Optics Module
For Simulating Electromagnetic Wave Propagation in Optically Large Structures
Software for Simulating Optical Design Components
The Wave Optics Module provides dedicated tools for electromagnetic wave propagation in linear and nonlinear optical media for accurate component simulation and optical design optimization. With this module you can model high-frequency electromagnetic wave simulations in either frequency- or time-domain in optical structures. It also adds to your modeling of optical media by supporting inhomogeneous and fully anisotropic materials, and optical media with gains or losses. Several 2D and 3D formulations are available in the Wave Optics Module for eigenfrequency mode analysis, frequency-domain, and time-domain electromagnetic simulation. You can calculate, visualize, and analyze your phenomena using postprocessing tools, such as computation of transmission and reflection coefficients.
Analysis for All Types of Optical Media
It is straightforward to simulate optical sensors, metamaterials, optical fibers, bidirectional couplers, plasmonic devices, nonlinear optical processes in photonics, and laser beam propagation. This can be done in 2D, 2D axisymmetric, and 3D spatial domains. Ports can be defined for inputs and outputs, as well as for automatic extraction of S-parameters matrices that contain the full transmission and reflection properties of an optical structure with, potentially, multiple ports. A variety of different boundary conditions can be applied to simulate scattering, periodic, and discontinuity boundary conditions. Perfectly-matched layers (PMLs) are ideal for simulating electromagnetic wave propagation into unbounded, free space while keeping computational costs down. The postprocessing capabilities allow for visualization, evaluation, and integration of just about any conceivable quantity, since you can freely compose mathematical expressions of fields and derived quantities.
Additional images:
- DRUDE-LORENTZ SLIT: An incoming plane wave pulse with a flat front and a Gaussian temporal shape is illuminated over a geometry consisting of a single dispersive slab with a subwavelength slit. Periodic boundary conditions are applied to create an array of slits.
- HEXAGONAL GRATING: A plane wave is incident on a reflecting hexagonal grating that consists of a protruding semisphere. Scattering coefficients for the different diffraction orders are calculated for several wavelengths.
- PHOTONIC CRYSTAL: A waveguide can be built using an array of high refractive index posts that has a photonic band gap. Over certain frequency ranges, good guiding is observed.
- PLASMONIC WIRE GRATING: An array of silver cylinders patterned on a substrate is modeled by one unit cell using Floquet periodicity. Higher-order diffraction is captured during the simulation.
- SCATTERING NANOSPHERE: A nanosized gold sphere is illuminated by a plane wave and the scattering is measured. The gold sphere is characterized by negative and complex-valued permittivity. The model results show the resistive heating losses on the sphere.
A Variety of Tools for Simplifying Optics Simulation
The Wave Optics Module allows for simulation of optical media with inhomogeneous, anisotropic, nonlinear, and dispersive material properties, such as conductivity, refractive index, permittivity, or permeability. To do this, COMSOL Multiphysics gives you access to the relevant 3-by-3 tensor, if your property is anisotropic, or allows you to enter any arbitrary algebraic equations for these material properties for nonlinear, inhomogenous, and dispersive materials. For sweeps over wavelength or frequency, you can define material properties that include expressions in the frequency or wavelength variable. This flexibility in accessing the underlying equations and mathematics that describe the material properties makes the Wave Optics Module perfect for modeling hard-to-describe materials, such as gyromagnetic and metamaterials with engineered properties. It also includes valuable features for simulating Floquet-periodic structures with higher-order diffraction modes, and graded index materials.
Consider the Effects of Other Phenomena on Wave Optics
As with all COMSOL products, the Wave Optics Module seamlessly integrates with COMSOL Multiphysics and the other add-on modules. That integration enables you to couple other physics with the propagation of electromagnetic waves. For instance, you can monitor laser heating, or the effect of structural stresses and deformations on the propagation of light through your optical devices and components.
Accurate Optical Modeling with the Innovative Beam Envelope Method
In time-dependent studies of electromagnetic wave propagation you often assume that all variations in time occur as sinusoidal signals, making the problem time-harmonic in the frequency domain. The Wave Optics Module has a number of interfaces for simulating such phenomena. You can also simulate nonlinear problems where the distortion of the signal is small, thanks to certain features included in the module. If the nonlinear influence is strong, a full time-dependent study of your device is required.
When solving optics propagation problems using traditional methods, a significant number of elements is required to resolve each propagating wave. Small wavelengths are invariably involved when simulating light propagation. Typically, large amounts of computational resources are required when you are modeling components and devices that are large as compared with the wavelength. Instead, the Wave Optics Module approaches these types of simulations using the innovative beam envelope method.
This novel method for electromagnetic full-wave propagation overcomes the need for traditional approximations, by direct discretization of Maxwell’s equations. Here, the electric field is expressed as the product of a slowly varying envelope function and a rapidly varying exponential phase function. This allows for accurate simulations of optically large systems where the geometric dimensions can be much larger than the wavelength, and where light waves cannot be approximated with rays. The conventional electromagnetic full-wave propagation method is also available in the Wave Optics Module, and can be appropriately used in smaller geometries.
Photonic Crystal
Photonic crystal devices are periodic structures of alternating layers of materials with different refractive indices. Waveguides that are confined inside of a photonic crystal can have very sharp low-loss bends, which may enable an increase in integration density of several orders of magnitude. This is a study of a photonic crystal waveguide. ...
Directional Coupler
Two embedded optical waveguides in close proximity form a directional coupler. The cladding material is GaAs and the core material is ion-implanted GaAs. The waveguide is excited by the two first supermodes of the waveguide structure - the symmetric and antisymmetric modes. Two numeric ports are used on both the exciting boundary and the ...
Modeling of Negative Refractive Index Metamaterial (Wave Optics)
It is possible to engineer the structure of materials such that both the permittivity and permeability are negative. Such materials are realized by engineering a periodic structure with features comparable in scale to the wavelength. It is possible to model both the individual unit cells of such a material, as well as, to model to properties of a ...
Step-Index Fiber Bend
The first part of the application computes the modes for a straight step index fiber made of silica glass. In the second part, a step index fiber bend with a 3 mm radius of curvature is analyzed with respect to propagating modes and radiation loss. It is shown how to find the power averaged mode radius and how to use this to compute the ...
Optical Scattering by Gold Nanospheres
This model demonstrates the simulation of the scattering of a plane wave of light by a gold nanosphere. The scattering is computed for the optical frequency range over which gold can be modeled as a material with negative complex-valued permittivity. The far-field pattern and losses are computed.
Plasmonic Wire Grating (Wave Optics)
In this model, a plane wave is incident on a wire grating on a dielectric substrate. Coefficients for transmission, reflection, and first order diffraction are computed for different angles of incidence The model is set up for one unit cell of the grating, flanked by Floquet boundary conditions describing the periodicity. As applied, this ...
Self-Focusing
A Gaussian beam is launched into BK-7 optical glass. The material has an intensity-dependent refractive index. At the center of the beam, the refractive index is the largest. The induced refractive index profile counteracts diffraction and actually focuses the beam. Self-focusing is important in the design of high-power laser systems. The model ...
Optical Ring Resonator Notch Filter
In its simplest form, an optical ring resonator consists of a straight waveguide and a ring waveguide. The waveguides are placed close to each other, making the light affect each between the two structures. If the propagation length around the ring is an integral number of wavelengths, the field becomes resonant and a strong field builds up in ...
Defining a Mapped Dielectric Distribution of a Metamaterial Lens (Wave Optics)
In this example, the properties of an engineered metamaterial are modeled by a spatially varying dielectric distribution. Specifically, a convex lens shape is defined via a known deformation of a rectangular domain. The dielectric distribution is defined on the undeformed, original rectangular domain and is mapped onto the deformed shape of the ...
Nanorods
A Gaussian electromagnetic wave is incident on a dense array of very thin wires (or rods). The distance between the rods and, thus, the rod diameter is much smaller than the wavelength. Under these circumstances, the rod array does not function as a diffraction grating (see the Plasmonic Wire Grating model). Instead, the rod array behaves as if ...