## Understanding Classical Gray Body Radiation Theory

##### Yosuke Mizuyama November 1, 2018

Even though the first man-made light source used thermal radiation, the effect wasn’t fully understood until the discovery of quantum mechanics. Nowadays, it’s a well-known physics concept. In this blog post, we discuss surface-to-surface radiation theory for the so-called gray body, how to implement it in the COMSOL Multiphysics® software, and an interesting use of this theory.

Read More##### Yosuke Mizuyama June 26, 2018

In a previous blog post, we discussed the paraxial Gaussian beam formula. Today, we’ll talk about a more accurate formulation for Gaussian beams, available as of version 5.3a of the COMSOL® software. This formulation based on a plane wave expansion can handle nonparaxial Gaussian beams more accurately than the conventional paraxial formulation.

Read More##### Yosuke Mizuyama January 8, 2018

In the wave optics field, it is difficult to simulate large optical systems in a way that rigorously solves Maxwell’s equation. This is because the waves that appear in the system need to be resolved by a sufficiently fine mesh. The beam envelopes method in the COMSOL Multiphysics® software is one option for this purpose. In this blog post, we discuss how to use the Electromagnetic Waves, Beam Envelopes interface and handle its restrictions.

Read More##### Yosuke Mizuyama June 15, 2017

The laser is one of the most useful inventions in modern science, but it is not an easy device to use. Lasers work only when the cavity mirrors are aligned perfectly. Even if a laser is lasing for a while, it can stop all of a sudden. In today’s blog post, we will talk about how to predict laser stability using the ray tracing capabilities in the COMSOL Multiphysics® software.

Read More##### Yosuke Mizuyama June 13, 2017

Ray tracing is an effective tool for high-frequency optics simulations. The Ray Optics Module for the COMSOL Multiphysics® software uses a multiphysics-capable wavefront method for its ray tracing. In this blog post, we’ll explore what makes the ray tracing algorithm in COMSOL Multiphysics distinct from traditional ray tracing algorithms described in standard geometrical optics textbooks and suggest a series of best practices to help you get the most out of your simulation results.

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##### 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##### 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.

Read More##### Yosuke Mizuyama April 14, 2016

We’ve learned how to simulate a simple bit-by-bit holographic data storage model in COMSOL Multiphysics by choosing an appropriate beam size and implementing the recording and retrieval process. Today, we step forward and demonstrate how to simulate a more difficult and complex, yet more realistic and interesting model of a holographic page data storage system.

Read More##### Yosuke Mizuyama April 5, 2016

Physicist and electrical engineer Dennis Gabor invented holography about 70 years ago. Ever since then, the form of optical technology has developed in many different ways. In this blog post, part one in a series, we talk about a specific industrial application of holograms in consumer electronics and demonstrate how to use COMSOL Multiphysics to simulate holograms in a wide spectrum of optical and numerical techniques.

Read More##### Yosuke Mizuyama February 15, 2016

Piezoelectricity finds use in a variety of engineering applications. They include transducers, inkjet printheads, adaptive optics, switching devices, cellphone components, and guitar pickups, to name a few. Today’s blog post will benefit both beginners and experts in piezoelectricity, as we highlight some of the fundamental elements of piezoelectric theory and basic simulations, along with a novel design for improving the range of motion for piezoelectric actuators.

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