A dual plasmon generator (PG) mirror image structure is used during fabrication of a TAMR head to locally anneal the PGs without substantially elevating the temperature in adjacent layers. Two PGs have narrow peg portions aligned head to head, and larger back end portions with a back side facing away from the eventual ABS. A first lead is attached to a back side of a first PG while a second lead is connected to a back side of a second PG. A 10 mA current is injected into a first PG and exits from the second PG and causes resistive heating in the rod-like portions where the temperature may be raised by 250° C. or more. A temporary overcoat layer may be formed over the PGs to dissipate heat and to keep the PGs from deforming during the annealing step.