Visible-light-band lateral dispersion multifocal metalens.

Area of Science:

• Optics and Photonics
• Nanotechnology
• Materials Science

Background:

• Traditional spectral separation techniques are often expensive and lack portability.
• Existing methods may struggle with focal plane tilt, complicating optical system design.

Purpose of the Study:

• To develop a compact, portable, and cost-effective spectral separation device.
• To demonstrate a metalens capable of focusing RGB light onto a co-planar focal plane.

Main Methods:

• Design and simulation of an RGB three-channel partitioned multi-focus metalens.
• Utilizing geometric phase principle with heterogeneous nanopillars for spectral selectivity.
• Investigating independent response to circularly polarized light at 405, 513, and 633 nm.

Main Results:

• The metalens successfully focuses red, green, and blue light to discrete lateral positions on a co-planar focal plane.
• Achieved focusing efficiencies of 56.63% (405 nm), 68.65% (513 nm), and 76.55% (633 nm).
• Focal spot sizes approached the diffraction limit, demonstrating high focusing performance.

Conclusions:

• The proposed metalens offers a robust planar-optic solution for miniature color imaging.
• This integrated device overcomes focal plane tilt issues inherent in traditional dispersion schemes.
• The technology enables advancements in portable multi-spectral imaging systems.