EMPossible Computational Electromagnetics Workshop at Kaunas University of Technology (KTU)
Day 1 - Finite Difference Frequency Domain (FDFD)
Day 1 of the workshop began with a seminar on popular CEM methods in photonics, which gave attendees a simple and visual overview of many of the most popular methods in computational electromagnetics to show the advantages and disadvantages of each. This comparison put them in a better position to evaluate the methods for application in their own specific design needs. The afternoon sessions were centered around the Finite-Difference Frequency-Domain (FDFD) method. Starting with Maxwell’s equations, the group saw how to derive every equation needed for a channel waveguide analysis. They worked on building a MATLAB code for their simulation, demonstrating the post process by visualizing the guided modes, and calculating phase constant, attenuation coefficient and effective refractive index. By the end of the session, every attendee had a working code that analyzed a rib waveguide commonly used in optical integrated circuits.
Day 2 - Slab Waveguides
Day 2 focused on analyzing slab waveguides. After deriving all the equations needed to evaluate the slab waveguide, Dr. Rumpf worked with attendees to code an analysis of a standard slab waveguide for both TE and TM modes, including plotting all the guided modes and displaying properties like effective refractive index. A second coding session used those same codes to calculate a surface plasmon polariton, which is a surface wave that exists at the interface between a dielectric and a metal.
Day 3 - Scattering Simulations
Day 3 centered on performing scattering simulations, such as Mie scattering or radar cross-section calculations. Dr. Rumpf led attendees through the derivation of all of the needed equations for FDFD. The afternoon session involved creating a working code that visualized a Gaussian Beam incident on a diffraction grating.
Day 4 - Periodic Structures
Day 4 of the workshop carried on from Day 3 to adopt the previous code to simulate a single period of a diffraction grating. This is a very powerful framework for simulations because all periodic structures (metamaterials, metasurfaces, photonic crystals, etc.) are simulated as if they were a diffraction grating. By putting periodic boundary conditions on the transverse boundary and leaving an absorbing boundary at the top and bottom, they were able to quickly calculate things like diffraction efficiency of the diffraction orders and overall reflectance and transmittance. By the end of the day, everyone was analyzing a binary diffraction grating and calculating the diffraction efficiencies of the diffraction orders for waves applied at any angle of incidence.
Day 5 - Transfer Matrix Method (TMM)
Another very full day, centered on a different numerical method, the Transfer Matrix Method (TMM). This method is particularly well suited for many of the structures students would encounter in their research at KTU. The first session introduced the method and derived all of the equations needed to implement as a code. The second session discussed details of the implementation, including a block diagram, that would be needed to implement the code. After a break, everyone coded the transfer matrix method to simulate a thin film device. Day 5 was concluded with a seminar on career development, which included topics such as personal branding, professional networking, resume advice, and advice for job interviews.
“I was thrilled to be able to return to Kaunas and the students at KTU to run a great workshop on computational electromagnetics. I met some fantastic students and have been inspired by the knowledge and interest of the students. I enjoyed seeing more of Lithuania and learning more about its intriguing history. A huge thank you to my friend and tour guide, Tomas Klinavicius, for making the trip such a success!” – Dr. Rumpf