## How to Model the Optical Properties of Rough Surfaces

##### Walter Frei June 6, 2017

Whenever light is incident on a dielectric material, like glass, part of the light is transmitted while another part is reflected. Sometimes, we add a metal coating, such as gold, which alters the transmittance and reflectance as well as leads to some absorption of light. The dielectric surface and the metal coating also often have some random variations in height and thickness. In this blog post, we will introduce and develop a computational model for this situation.

Read More##### Bridget Cunningham April 17, 2017

Optical fibers that deliver midinfrared wavelengths are in high demand for a range of relative applications. As infrared transparent materials, semiconductors are useful for this purpose when combined with silica, helping to realize a new generation of midinfrared fiber optics. While important to performance, measuring the optical losses of such structures can be challenging experimentally because of time and costs. Simulation enables us to efficiently model this behavior for varying wavelengths and fiber geometries and identify strategies to reduce losses.

Read More##### Yosuke Mizuyama February 27, 2017

We previously learned how to calculate the Fourier transform of a rectangular aperture in a Fraunhofer diffraction model in the COMSOL Multiphysics® software. In that example, the aperture was given as an analytical function. The procedure is a bit different if the source data for the Fourier transformation is a computed solution. In this blog post, we will learn how to implement the Fourier transformation for computed solutions with an electromagnetic simulation of a Fresnel lens.

Read More##### Caty Fairclough February 17, 2017

While electro-optic (EO) routers are currently used in on-chip optical communication systems, they may require too much power for some applications. In these situations, we can look to monolithically integrated magneto-optic (MO) routers as low-power alternatives. Designing these routers can be challenging. With multiphysics simulation, we can analyze on-chip MO routers and the manufacturing techniques used to create them.

Read More##### Andrew Strikwerda January 30, 2017

Welcome back to our discussion on multiscale modeling in high-frequency electromagnetics. Multiscale modeling is a simulation challenge that arises when there are vastly different scales in a single simulation, such as the size of an antenna compared to the distance between the antenna and its target. Today, in Part 4 of the series, we will examine how we can construct a multiscale model by coupling a Full-Wave antenna simulation with a geometrical optics simulation using the Ray Optics Module.

Read More##### Andrew Strikwerda January 18, 2017

In Part 3 of our series on multiscale modeling in high-frequency electromagnetics, let’s turn our attention to the receiving antenna. We’ve already covered theory and definitions in Part 1 and radiating antennas in Part 2. Today, we will couple a radiating antenna at one location with a receiving antenna 1000 λ away. For verification, we will calculate the received power via line-of-sight transmission and compare it with the Friis transmission line equation that we covered in Part 1.

Read More##### Andrew Strikwerda January 12, 2017

In Part 2 of our blog series on multiscale modeling in high-frequency electromagnetics, we discuss a practical implementation of multiscale techniques in the COMSOL Multiphysics® software. We will simulate radiated fields using two different techniques and verify our results with theory. While these methods can be generally applied, we will always revolve around the practical issue of antenna-to-antenna communication. For a review of the theory and terms, you can refer to the first post in the series.

Read More##### Andrew Strikwerda January 11, 2017

This post begins a comprehensive blog series where we will look at several approaches to multiscale modeling in high-frequency electromagnetics. Today, we will introduce the supporting theory and definitions that we will need. In subsequent posts, you will learn how to implement multiscale modeling of high-frequency electromagnetics for different scenarios in the COMSOL Multiphysics® software. Let’s get started…

Read More##### Yosuke Mizuyama September 21, 2016

The Gaussian beam is recognized as one of the most useful light sources. To describe the Gaussian beam, there is a mathematical formula called the paraxial Gaussian beam formula. Today, we’ll learn about this formula, including its limitations, by using the Electromagnetic Waves, Frequency Domain interface in the COMSOL Multiphysics® software. We’ll also provide further detail into a potential cause of error when utilizing this formula. In a later blog post, we’ll provide solutions to the limitations discussed here.

Read More##### Abbie Weingaertner September 12, 2016

Polarizing beam splitters are optical devices used to split a single light beam into two beams of varying linear polarizations. These devices are useful for splitting high-intensity light beams like lasers as, unlike absorptive polarizers, they do not absorb or dissipate the energy of the rejected polarization state. See why creating a numerical modeling app offers a more efficient approach to analyzing and optimizing the design of these devices.

Read More##### Yosuke Mizuyama May 30, 2016

In a previous blog post, we discussed simulating focused laser beams for holographic data storage. In a more specific example, an electromagnetic wave focused by a Fourier lens is given by Fourier transforming the electromagnetic field amplitude at the lens entrance. Let’s see how to perform this integral type of preprocessing and postprocessing in COMSOL Multiphysics with a Fraunhofer diffraction example.

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