Fabrication of micro-optical components in polymer using proton beam micro-machining and modification

Proton beam micro-machining (PBM) is a direct write lithographic technique that utilizes a high energy (MeV) sub-micron focused proton beam to machine or modify a material, usually a polymer. The technique has been developed in recent years at the Research Centre for Nuclear Microscopy, National University of Singapore where structures with feature sizes of well below 1 μm have recently been demonstrated. The PBM technique has several desirable features that make it suitable for rapid prototyping of micro-optical components. Structures made using PBM have very smooth side walls, high aspect ratio, and a scale that can be easily matched to existing optical fiber technology (0.1-1000 μm). Furthermore, PBM can also be used to modify the optical properties of polymers, particularly if the end of range is used. In this paper we demonstrate the use of proton beam micro-machining and modification for manufacturing micro-optical components in positive and negative resist. The structures that are fabricated can be used for both rapid prototyping and for large scale replication.