Method of testing thermally-assisted magnetic head

A method of testing a thermally-assisted magnetic head, the method comprising:

• providing a slider body having a waveguide embedded therein with an incidence end extending toward a back surface of the slider body;
• providing a light source unit including a light source and a unit substrate for supporting the light source;
• coating a bonding material layer on the back surface, under the bottom, or both on the back surface and under the bottom of the unit substrate;
• coating a localization material layer on the back surface to cover the incidence end of the waveguide;
• aligning the light source unit to the slider body;
• causing a light emitted from the light source and allowed to be incident on the incidence end of the waveguide to anneal the localization material layer to generate an annealing mark;
• removing the light source unit or the light source from the slider body;
• and
• measuring a position offset between the annealing mark of the localization material layer and the incidence end of the waveguide.