Modified Thue–Morse zone plates with arbitrarily designed high-intensity twin main foci

We present a modified Thue–Morse zone plate (MTMZP), which comprises periodic structure based on the third order Thue–Morse zone plate (TMZP). The MTMZP generates twin main foci along the axis, and arbitrary axial positions of the twin foci can be designed. Compared with the TMZP, the MTMZP of the same order has much higher-intensity foci. The axial positions of the twin foci of the MTMZP are found to satisfy the proportional relationship of 3/5. Furthermore, the self-reconstruction property of the MTMZP beam is verified with numerical simulation. The MTMZPs have potential applications in optical trapping and optical imaging. (paper)