Multiwavelength achromatic microlens through phase compensation based on the subwavelength metallic nanostructures

摘要

Chromatic aberration has been a functional distortion for the emerging microlens owing to phase mismatch, thus an extensive challenge is to achieve achromatic microlens over a broad wavelength range because it is difficult to achieve engineer simultaneous phase profiles at distinct wavelengths. For practical applications, a further challenge is to create an achromatic microlens with uncomplicated structure that can work in the transmission mode for incident light waves. In this work, we design a special and uncomplicated structure to achieve achromatic focusing based on the metallic silver subwavelength nanostructures, grating bars in our work, the structure can be regarded as a metal-insulator-metal (MIM) waveguide via exciting the surface plasmon polaritons (SPPs) mode to produce the phase retardation that could compensate and correct phase, thus we can obtain an achromatic microlens with uncomplicated structure over the whole visible, which do not need excessive requirement for the fabrication technology. The low-cost and manufacture compatibility make our achromatic microlens suitable for applications in nanophotonics and integrated optics in the visible.