We spend our lives surrounded by light, yet few of us have even a rudimentary understanding of how it moves through space. Instead, we make analogies to water, something we can readily see and touch: light “streams” through clouds, “flows” through windows and “bathes” us in its brilliance. But truly comprehending the movement of photons — massless elementary particles that are the basic unit of all light — requires a rarefied level of math and physics that’s accessible to only a select few scientists.
One of those is Pennsylvania State University’s Mikael Rechtsman, a leading figure in the field of topological physics who, a decade ago, was an Azrieli International Postdoctoral Fellow at Technion–Israel Institute of Technology. Topology is the mathematical study of shapes and their arrangement in space. Simply put, Rechtsman explores not just how light moves through open space, but also how light moves through substances such as glass and how that travel can be manipulated by materials with complex geometries.
Perhaps the best example of this movement is in optical fibres. These long, thin glass “tubes” guide light in much the same way that wires guide electricity. In fact, they can carry dramatically more information than wires and require far less power to do so. As a result, optical fibres form the backbone of the modern internet’s infrastructure. This technology and other developments have pushed forward the photonics industry, which augments and complements parallel developments in the electronics industry.