Wave Optics Module
Wave Optics Module
For Simulating Electromagnetic Wave Propagation in Optically Large Structures
Directional coupler formed from two interacting waveguides.
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.
- A Gaussian beam is launched into a BK-7 optical glass, where the refractive index is largest at the center of the fiber, and which counteracts the diffractive effects and actually focuses the beam. The figure indicates a compressed view, and the true aspect ratio of the fiber used in the simulation.
- Energy density within a Fabry-Perot cavity over a range of frequencies. With this, you can find the resonant frequencies and Q-factors.
- A gold sphere is illuminated by a plane wave and the scattering is measured. The far-field radiation pattern in the E-plane (blue) and H-plane (green) is shown, along with the resistive heating losses.
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.
Surface Plasmon Resonance
Sergei Yushanov, Jeffrey S. Crompton, Luke T. Gritter, and Kyle C. Koppenhoefer AltaSim Technologies Columbus, OH USA
Surface Plasmon Resonance (SPR) is created by surface plasmons, coherent electron oscillations existing between any two materials where the real part of the dielectric function changes sign across the interface. SPR technology is based on the electromagnetic field component of incident light penetrating into a surface and it can be used to detect ...
Metamaterials Make Physics Seem Like Magic
David Smith & Yaroslav Urzhumov Duke University Pratt School of Engineering Durham, NC Jeff Wilson NASA Glen Research Center, Cleveland, OH Fabio Alves and Gamani Karunasiri Naval Postgraduate ...
Metamaterials are manufactured, structured materials that they can interact and manipulate wave phenomena such that objects surrounded by metamaterials are shielded from these waves. In the case of light, metamaterials make these objects ‘invisible’. Researchers throughout the world are applying these materials to many different ...
A 100-Fold Improvement in Lithography Resolution Realized with a 150-Year-Old “Perfect Imaging” System
Juan Carlos Miñano and Dejan Grabovičkić Cedint Polytechnic University of Madrid Spain
The idea of "perfect imaging", that is a resolution less than the wavelength of light producing the image, was first proposed in the mid-19th century by famed Scottish physicist James Clerk Maxwell. For the next 150 years, it was widely believed that such was impossible due to the fact that light diffracts around points that are the same size or ...
Plasmonic Wire Grating
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 of an Optical Beam
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 ...
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. The ...
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 absorbing ...
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 it ...
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.
Modeling of Negative Refractive Index Metamaterial
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 ...
The low transmission loss and inherently large bandwidth are the two main advantages of optical waveguides compared to microwave waveguides. Thus, for communication over long distances or for high bitrates, optical fibers are preferred over electrical cables. This model is an example of a single step-index waveguide made of silica glass. The ...
Defining a Mapped Dielectric Distribution of a Metamaterial Lens
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 ...
This is an example of a Fabry-Perot cavity, the simplest optical resonator structure. It is a classical problem in optics and photonics. Two methods are shown for computing the Q-factor. The losses in this model are purely via radiation away from the resonator.