2020 New Initiative Grant
Mikael Rechtsman, Ph.D. (PI) Associate Professor, Department of Physics. Pennsylvania State University
Randall McEntaffer, Ph.D. (co-investigator) Professor, Department of Physics and Astrophysics, Pennsylvania State University
Magnetizing light: from X-ray astronomy to silicon photonics
Magnetic fields are used universally across a range of technologies as well as fundamental science to control and manipulate charged particles, like electrons. The central goal of the research proposed here is to make photons – particles of light, which carry no charge – “feel” a magnetic field. This could potentially enable a wide range of new functionalities for photonic devices. In contrast to electrons, photons are entirely unaffected by magnetic fields - they pass through them unimpeded. Given the wide-ranging importance of magnetism in both fundamental and applied electronics (from the quantum Hall effect to computer memory), it has been a major open problem to find ways in which light can be strongly affected by magnetic fields. Specifically, “pseudomagnetism” could be used to create radically different and more efficient lasers, as well as highly compact light sources for medical imaging techniques such as optical coherence tomography. Our approach to achieve pseudomagnetism for photons is based on a discovery from about 10 years ago: that imposing an inhomogeneous strain on a two-dimensional material (a one-atom thick plane) can make its electrons behave as though there were a magnetic field present – even in the absence of one. We will take a nanofabricated “photonic crystal” structure, composed of a slab of silicon with a lattice of nanoscale triangular holes etched it, and effectively strain it to induce artificial magnetic fields for photons. Here, we will draw on the techniques of X-ray astronomy, where intricate fabrication of nanoscale structures over large areas are necessary. This interdisciplinary project interweaves the complementary expertise of primary investigator Mikael C. Rechtsman in photonic device design and co-primary investigator Randall McEntaffer in nanofabrication of gratings for X-ray telescopes.