This image shows picophotonics in the 3D lattice of silicon atoms. The red wave represents the conventional electromagnetic wave propagating in the solid; the blue inner wave represents the newly predicted picophotonic wave. Image: Purdue University/Zubin Jacob.Researchers at Purdue University have discovered new electromagnetic waves with picometer-scale spatial variations that can propagate in semiconductors like silicon. The research team, led by Zubin Jacob, associate professor of electrical and computer engineering, report their findings in a paper in Physical Review Applied.
“The word microscopic has its origins in the length scale of a micron, which is a million times smaller than a meter,” says Jacob. “Our work is for light-matter interaction within the picoscopic regime, which is far smaller, where the discrete arrangement of atomic lattices changes light’s properties in surprising ways.”
These intriguing findings demonstrate that natural media host a variety of rich light-matter interaction phenomena at the atomistic level. The use of picophotonic waves in semiconducting materials could lead researchers to design new functional optical devices, allowing for applications in quantum technologies.
Light-matter interaction in materials is central to several photonic devices, from lasers to detectors. Over the past decade, nanophotonics, the study of how light flows at the nanometer scale in engineered structures such as photonic crystals and metamaterials, has led to important advances.
The research to-date can be captured within the realm of the classical theory of atomic matter. The current finding leading to picophotonics was made possible by a major leap forward using a quantum theory of atomistic response in matter.
The long-standing puzzle in the field was the missing link between atomic lattices, their symmetries and the role they play in deeply picoscopic light fields. To answer this puzzle, the theory team combined a Maxwell Hamiltonian framework of matter with a quantum theory of light-induced response in materials.
“This is a pivotal shift from the classical treatment of light flow applied in nanophotonics,” says Jacob. “The quantum nature of light’s behavior in materials is the key for the emergence of picophotonics phenomena.”
The researchers showed that hidden amidst traditional well-known electromagnetic waves, new anomalous waves can emerge in the atomic lattice. These light waves are highly oscillatory, even within one fundamental building block of the silicon crystal (sub-nanometer length scale).
“Natural materials itself have rich intrinsic crystal lattice symmetries and light is strongly influenced by these symmetries,” says Sathwik Bharadwaj, a research scientist at Purdue University. “The immediate next goal is to apply our theory to the plethora of quantum and topological materials and also verify the existence of these new waves experimentally.”
“Our group has been leading the frontier of research on picoscale electrodynamic fields inside matter at the atomistic level,” says Jacob. “We recently initiated the picoelectrodynamics theory network, where we are bringing together diverse researchers to explore macroscopic phenomena stemming from microscopic pico-electrodynamic fields inside matter.”
This story is adapted from material from Purdue University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.