The optics and photonics fields are creating groundbreaking applications for astronomy, telecommunications, sensing, chemistry, biomedical research & development.

Recently, researchers from Pennsylvania State University demonstrated how metasurfaces with unparalleled controllability of light may be able to transform traditional optics. To do so, they used a simulation that applied the finite element method (FEM).

As discussed in a previous post, 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 pick apart. This equation is then used to create a simulation (known as the finite element analysis), which gives engineers a more detailed analysis into the design and how its various elements work together.

#### How Engineers Used FEM to Demonstrate the Potential of Metasurfaces

“Metasurfaces” are thin, two-dimensional metamaterial layers that permit or prevent the propagation of electromagnetic waves in desired directions. They are thought to have enormous potential to transform traditional optics technology.

However, metasurfaces do pose some problems. For instance, metasurfaces depend on the excitation of external light. Because of this, it’s challenging to integrate the layers completely onto a single chip. Conversely, while integrated photonics allows optical components to be packed compactly onto a chip, there’s not enough space to control light.

The Pennsylvania State researchers found a solution: they dressed metasurfaces onto waveguides. These structures can guide waves—including electromagnetic waves. By doing this, they molded guided waves into the free-space modes they desired. The process allowed them to create complex free-space functions, like out-of-plane beam deflection and focusing.

Using FEM simulations, the researchers demonstrated a feasible way to control light on integrated photonics and free-space metasurfaces. The study may represent a path forward for scientists to be able to make multifunctional photonic integrated devices with the ability to easily access free space, allowing for a range of advancements in optical communications.

“We have experimentally demonstrated off-chip beam deflection and focusing using the guided wave driven metasurfaces on silicon waveguides. In addition, two-dimensional (2D) manipulation of free-space light can be realized by placing a 2D array of meta-atoms on a slab waveguide. This technology can enable a wide spectrum of applications ranging from optical communications to LiDAR, as well as miniaturized display technology for virtual reality and augmented reality devices,” the researchers wrote in *Science Advances*.

This study is just one example of how researchers are using FEM to make breakthroughs in optics and photonics. Another team of researchers recently used FEM to demonstrate a potential new way to develop innovative applications in quantum communications and information processing.

#### Finite Element Method (FEM) for Photonics

This 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.

Contact an IEEE Content Specialist today to learn more about getting access to these courses for your organization.

Interested in the course for yourself? Visit the IEEE Learning Network.

#### Resources

*Chen, Xi, Ding, Yimin, Duan, Yao, Guo, Xuexue, Ni, Xingjie (17 July 2020). Molding free-space light with guided wave–driven metasurfaces. ScienceAdvances.*

*The Benefits of Finite Element Analysis in Manufacturing. Manor Tool.*

*Agrawal, Arti , Rahman, B. M. Azizur. (2013). Finite Element Modeling Methods for Photonics. Artech House. *

Growing innovations in silicon photonics are driving the growth of the photonics industry around the globe.