High Efficient Tunable Fractal Axicon Based on LCoS

Based on the Cantor function and phase modulation, a tunable fractal axicon is formed on a liquid crystal on silicon (LCoS) with an improved generating method. It has higher focusing efficiency in higher fractal stage and approaches to 100% theoretically. The on-axis intensity keeps its fractal structure unchanged in operation of fractal stages. The tunability of the
axicon is demonstrated by tune fractal stage from 1 to 3 and focal length from 0.8m to 1m. We also provide details of theoretical analyses and experimental results.