Photonics is the science of producing, manipulating, and discovering light waves and photons (light particles). The field covers a number of technologies like lasers and fiber-optics. The finite element method (FEM) can be used to create a range of photonics applications that can be used in astronomy, telecommunications, sensing, chemistry, biomedical R&D, and more.
How is the Finite Element Method Used in Photonics?
FEM is a numerical solution for a complex problem, which breaks down a much larger problem into a series of smaller ones (“finite elements”), making the overall problem easier to decipher. This equation is then used to create a simulation, or what’s known as the finite element analysis. This simulation is then used by engineers to test how different elements of a design react to different simulated stressors. FEM is a popular technique among engineers to effectively simulate photonics devices and components in order to understand how they will react and behave under external environmental factors. It has been fueling breakthroughs in photonics.
How FEM is Helping Photonics Researchers Make Discoveries
Recently, researchers used FEM to analyze topologically protected four-wave mixing (FWM) interactions in a plasmonic metasurface made up of intermittent arrangements of nanoholes in a graphene sheet. This demonstrated a broad topological energy gap at terahertz frequencies during the breaking of time reversal symmetry by a static magnetic field. The scientists revealed that they were able to achieve a net gain of FWM synergy of plasmonic edge states within the topological bandgap with a pump power of less than 10 nW. Additionally, they demonstrated that the adequate nonlinear edge-waveguide coefficient is over 10 orders of magnitude greater than that of highly nonlinear silicon photonic nanowires that are typically employed.
“These findings could pave a new way for developing ultralow-power-consumption, highly integrated, and robust active photonic systems at deep-subwavelength scale for applications in quantum communications and information processing,” the researchers write in Science Advances.
Surface-emitting semiconductor lasers can be used for sensing, data communications, facial recognition, and augmented reality glasses. In a recently published report, researchers from the U.S., Korea, and Canada, documented the first-ever all-epitaxial, distributed Bragg reflector (DBR)-free, electrically injected surface-emitting green laser. The team used a 2D-FEM simulation to test the design.
“The results provided strong evidence on achieving coherent lasing oscillation in InGaN nanocrystal arrays,” writes Thamarasee Jeewandara in Phys.org. “The scientists measured the electroluminescence spectra to demonstrate remarkably stable and directional polarized emission, compared to conventional photonic crystal laser devices.”
Scientists are also using FEM to examine how topological protection can be applied to photonics to create new ways of directing and controlling quantum information. For example, one group of researchers recently demonstrated that spin-orbit coupling can produce helical edge states, demonstrating one-way propagation that topologically safeguards against backscattering.
The scientists witnessed the electronic materials’ photonic analog topological states undergoing the quantum spin Hall effect, which occured in-between a pair of silicon photonic crystals consisting of different topological order. The researchers used the associated innate far-field radiation to label their properties, such as linear dispersion and low loss.
“We find that the edge state pseudospin is encoded in unique circular far-field polarization and linked to unidirectional propagation, thus revealing a signature of the underlying photonic spin-orbit coupling,” the scientists write. “We use this connection to selectively excite different edge states with polarized light and directly visualize their routing along sharp chiral waveguide junctions.”
Finite Element Method (FEM) for Photonics
The new course program from IEEE Educational Activities, Finite Element Method for Photonics, provides a comprehensive and up-to-date account of FEM in photonics devices, with an emphasis on practical, problem-solving applications and real-world examples. Engineers will come away from this program with an understanding of how mathematical concepts translate to computer code finite element-based methods.
Connect with an IEEE Content Specialist today to learn how to get access to this program for your organization.
Interested in the course for yourself? Visit the IEEE Learning Network (ILN).
Wei You, Jian, Lan, Zhihao, and Panoiu C, Nicolae. (27 March 2020). Four-wave mixing of topological edge plasmons in graphene metasurfaces. Science Advances.
Parappurath, Nikhil, Alpeggiani, Filippo, Kuipers, L., and Verhagen, Ewold. (6 March 2020). Direct observation of topological edge states in silicon photonic crystals: Spin, dispersion, and chiral routing. Science Advances.
Jeewandara, Thamarasee. (16 January 2020). An electrically pumped surface-emitting semiconductor green laser. PHYS.ORG.
Agrawal, Arti , Rahman, B. M. Azizur. (2013). Finite Element Modeling Methods for Photonics. Artech House.