Development of magnetic responsive random lasers fabricated by a laser-induced surface roughness

A magnetic responsive random laser was developed by roughening the surface of a NiFe alloy thin film-coated GaN substrate using an intense laser. By dispersing the magnetic materials and fabricating a surface roughness on the GaN surface after irradiation with intense laser pulses, we confirmed that the threshold of the random laser can be changed by applying an external magnetic field on the substrate. This result suggests that the magneto-optical effect of the residual NiFe alloy on the surface changes the local random feedback, leading to a change in the lasing behavior. Thus, we developed a simple method to fabricate a magnetically responsive random laser directly on a semiconductor substrate using only short laser irradiation.