High-performance achromatic flat lens by multiplexing meta-atoms on a stepwise phase dispersion compensation layer

Area of Science:

• Optics and Photonics
• Materials Science

Background:

• Flat optics offer miniaturization of optical systems by manipulating wave properties.
• Achromatic flat lenses are crucial for advanced optical applications, but face challenges in achieving high numerical aperture, broad bandwidth, and large aperture sizes simultaneously.

Purpose of the Study:

• To overcome limitations in achromatic flat lens design, specifically regarding high numerical aperture and aperture size expansion.
• To develop a novel method for creating ultra-thin, high-performance achromatic flat lenses.

Main Methods:

• Introduced zone division multiplexing of meta-atoms on a stepwise phase dispersion compensation (SPDC) layer.
• Designed SPDC layers to enable free enlargement of aperture size by adjusting optical thickness differences.
• Fabricated two achromatic flat lenses with 500 nm thickness, covering a 650-1000 nm bandwidth.

Main Results:

• Achieved two achromatic flat lenses: one with NA 0.9 and radius 20.1 µm, another with NA 0.7 and radius 30.0 µm.
• Demonstrated microscopic imaging with 1.10 µm resolution using white light illumination.
• These lenses represent the highest numerical apertures, largest aperture sizes, and thinnest thicknesses reported for broadband achromatic flat lenses.

Conclusions:

• The zone division multiplexing on SPDC layers effectively addresses challenges in achromatic flat lens design.
• The developed flat lenses exhibit unprecedented performance, paving the way for practical applications in miniaturized optical systems.
• This advancement signifies a substantial step towards realizing the full potential of flat optics.