Height/width aspect ratio controllable two-dimensional sub-micron arrays fabricated with two-photon photopolymerization

We reported in this paper the use of annular beam illumination to control the transverse and vertical sizes of two-dimensional dot array structures fabricated with two-photon photopolymerization. Dot arrays with an element diameter of less than 300 nm, a lattice spacing less than 1 mum has been produced. At the same time, the structure height exhibits a 1.94 times increase averagely and the height/width aspect ratio is improved from 1.21, for the circular beam illumination case, to 2.76 after using annular beam illumination.