Professor Refael explores the possiblity of realizaing topological frequency converters in Weyl semimetals.

Electrons close to the Weyl points are expected to convert energy between the frequencies through the mechanism outlined in [Martin et al, PRX 7 041008 (2017)]. Each electron converts energy at a quantized rate given by an integer multiple of Planck’s constant multiplied by the product of the two frequencies. He will explore the working principle as well as present results from simulations. He shows that optimal, but feasible band structures can support topological frequency conversion in the “THz gap” at intensities down to 2W/mm2; the gain from the effect can exceed the dissipative loss when the frequencies are larger than the relaxation time of the system.