Metallic cylindrical focusing micromirrors with long axial focal depth or increased lateral resolution

Abstract

Using a general focal-length function, two-dimensional long-focal-depth (LFD) metallic cylindrical focusing micromirrors (MCFMs) are designed and the focal performance is systematically investigated based on rigorous electromagnetic theory and the boundary element method. For a positive preset focal depth, simulation results reveal that the designed MCFMs still possess an LFD property and high lateral resolution even when the f-number is reduced to f/0.3. On the other hand, through setting the preset focal depth to be negative, increased lateral resolution is obtained, compared with the conventional MCFM. In addition, under multiwavelength illumination, a large common LFD region is demonstrated for the designed LFD MCFMs, which is due to the intrinsic achromatic property of reflective systems.

Uniform axial intensity distributions of long-focal-depth cylindrical micromirrors realized by an amplitude-phase modulation method

“…As we know, cylindrical micromirrors are superior to cylindrical microlenses due to a higher normalized encircled energy and the achromatic aberration property [28,29]. In this paper, we extend our previous research on dielectric focusing microlenses to metallic cylindrical focusing micromirrors (MCFMs).…”

“…In the past literatures, the LFD MCFM was often designed by the PPMM [28,29], whose focal length f is written as [29] f where f 0 and δf represent the beginning focal length and the preset focal depth, respectively. On substituting Equation (2) into Equation (1), we can derive the boundary function of the pure phase-modulated LFD MCFM as…”

“…After designing the MCFM and optimizing the parameter pair (ρ 0 , ω), performance of the MCFM is rigorously analyzed by the BEM. Because the BEM has been described in detail in many previous works [28][29][30], we will not repeat it in this paper.…”

Inverse designed metalenses with extended depth of focus

“…For these lenses, however, different parts of the of the lens focus at different depths, significantly limiting the focusing efficiency. In one dimension, several works theoretically explored cylindrical EDOF lenses [25][26][27][28] , although to the best of our knowledge no experimental demonstration has previously been reported.…”

A Monotonic-Increasing-Thickness Model for Designing Cylindrically Diffractive Focusing Micromirrors and Micromirror Arrays

“…D UE to the good properties of achromatic aberration and high focusing efficiency, cylindrically focusing mirrors are intensively studied [1]- [9]. The traditional mirrors have a large thickness, which are difficult to fabricate.…”