Shaping the profile of photonic crystal nanorods

The focused ion beam technique is a frequently used method to manufacture photonic crystal structures due to its capability of defining patterns in a wide range of materials without using masks. One critical drawback of FIB milling technique is the non-vertical profile resulted from redeposition effects during lithography. Tapered sidewalls may impact the performance of the fabricated device significantly. In a previous work, we have shown it is possible to shape the profile of nanoholes by truncating the seriously tapered bottoms. Here, we report on the re-definition of nanorod photonic crystals using focused ion beam milling. The proposed method is simple and entirely monolithic.