A new method to fabricate optical microstructures with different profiles such as spherical and aspherical outlines is discussed.The most key technological step is a two-step anisotropic etching of KOH:H2O to(100) silicon substrate with resistant mask in which many circular openings are preshaped.The size of these openings is according to the feature appearance of the final structure.A pattern structure in substrate can be formed through connecting many small concave spherical structures formed by chemical ...