Creating traveling waves from standing waves from the gyrotropic paramagnetic properties of Fe 3+ ions in a

We report observations of the gyrotropic change in magnetic susceptibility of the Fe 3+ electron paramagnetic resonance at 12.037GHz (between spin states|1/2 > and |3/2 >) in sapphire with respect to applied magnetic field. Measurements were made by observing the response of the high-Q Whispering Gallery doublet (WGH±17,0,0) in a Hemex sapphire resonator cooled to 5 K. The doublets initially existed as standing waves at zero field and were transformed to traveling waves due to the gyrotropic response.