Gratings in GaN membranes

In this work, gratings are fabricated on the GaN thin film grown on the silicon substrates. GaN membranes are obtained by removing the silicon below the GaN gratings. The samples are stacked on the GaN diffractive microlenses on sapphire substrates fabricated using gray-level masks. The stacked components are characterized using a He-Ne laser. The laser beam is collimated by the GaN microlenses and diffracted by the GaN gratings. The result demonstrates a stacked microoptics systems in GaN-based materials for the first tune.