3D Nanoscale Chiral Helixes Fabricated by Focused Helium Ion Beam Manufacturing Process

As chiral structures, three-dimensional (3D) nanohelixes have the circular dichroism and optical rotation under circularly polarized light. It also has a good application prospect in optical modulators with high modulation efficiency. However, it is still a challenging task to fabricate 3D nanohelixes with high precision, controllable parameters and perfect morphology. In this study, we develop FIB (focused ion beam)-SID (stress induced deformation) by using HIB (helium ion beam) instead of GIB (gallium ion beam) for nanofabrication. This general 3D nanofabrication technique allows much stronger manufacturing control, which lead to a greater programmable and accurate bidirectional folding $(-160^{\circ}-+75^{\circ})$ of various metal and dielectric thin films. Higher manufacturing accuracy of HIB makes it possible to fabricate smaller nanostructures (characteristic size is about 100 nm), which provides strong support for 3D nanostructure fabricated in visible light wave band.