Optica 2, 635–641 (2015)

Credit: OSA

Optomechanical interactions in a photonic crystal lattice can be used to create artificial magnetic fields and non-reciprocal photon edge states that are immune to backscatter. That's the prediction of a theoretical investigation recently published by a collaboration between scientists at the University of Erlangen-Nürnberg in Germany and Caltech in the USA. The team says that by illuminating a patterned dielectric slab with two laser beams with suitably engineered optical phases and amplitudes it should be possible to induce optomechanical interactions that result in photon transitions that yield an arbitrary magnetic flux distribution. Two optomechanical approaches — modulated photon transitions and wavelength conversion — are considered by the team and their analysis suggests that both should be experimentally viable if fabrication-induced disorder can be reduced to a sufficiently low level. The scientists say that the attraction of the optomechanical approach to the creation of non-reciprocal states is that it is controlled all-optically rather than requiring electrodes or relying on the geometry of a structure and thus offers the opportunity for in situ tunability and great flexibility.