In one example, a method comprises forming a first layer on a substrate surface, forming an opening in the first layer, forming a second layer on the first layer and in the opening, and forming a photoresist layer on the second layer, in which the photoresist layer has a first curved surface over a first part of the first layer and over the opening. The method further comprises etching the photoresist layer and a second part of the second layer over the first part of the first layer to form a second curved surface on the second part of the second layer, and forming a mirror element and a support structure in the second layer, including by etching a third part of the second layer and removing the first layer.