the photonic crystal having the at least one ferromagnetic control rod which controls the magnetic field in {HEAD ~ the photonic crystal} wherein {TAIL ~ the at least one ferromagnetic control rod} is in turn controlled by a controllable external current 
wherein
the photonic crystal having the at least one ferromagnetic control rod which controls the magnetic field in { HEAD ~ the photonic crystal } wherein { TAIL ~ the at least one ferromagnetic control rod } is in turn controlled by a controllable external current
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH