Experimental work led by physicists at Queens College, City University of New York (CUNY; Flushing, NY) in collaboration with City College of CUNY (New York, NY) combined with theoretical work from Purdue University (West Lafayette, IN) and the University of Alberta (Edmonton, AL, Canada) has uncovered a new method to manipulate light by borrowing an idea from the field of mathematical topology.1 The researchers have created an artificial material that can transform itself from a regular dielectric (a substance like glass or plastic that does not conduct electricity) to a medium that behaves like metal (reflects) in one direction and like a dielectric (transmits) in the other.
Optical properties of this artificial material can be mapped onto a topological transformation of an ellipsoidal surface into a hyperboloid. The topological transition from such a bound (elliptic) to an unbound (hyperbolic) surface manifests itself in the real world as a dramatic increase in the light intensity inside the material and increased rates of spontaneous emission of emitters positioned near the metamaterial. Altering the topology of the iso-frequency surface provides a fundamentally new route to manipulating light-matter interactions, with demonstrated modification of the light emission for a nanoparticle placed in the vicinity of the artificial material. Such media could find applications in solar cells, light-emitting diodes (LEDs), ultrasensitive sensors, and for quantum computers.
REFERENCE
1. H.N.S. Krishnamoorthy et al., Science, 336, 6078, 205–209 (Apr. 13, 2012).