Beating spectral bandwidth limits for large aperture broadband nano-optics

Area of Science:

• Optics
• Computational Imaging
• Materials Science

Background:

• Diffractive flat optics face limitations due to chromatic aberrations, hindering broadband, high-quality imaging, especially for fast, large-aperture systems.
• Existing flat optics struggle to achieve true broadband imaging in the visible spectrum, limiting applications in advanced imaging and sensing.
• Overcoming spectral bandwidth limitations is crucial for realizing the full potential of flat optics in next-generation optical systems.

Purpose of the Study:

• To overcome the intrinsic spectral bandwidth limitations of diffractive flat optics.
• To achieve broadband imaging in the visible wavelength range using a novel flat meta-optic.
• To challenge the established notion that high-quality, full-color images cannot be captured by a single large-aperture meta-optic.

Main Methods:

• Co-designing a flat meta-optic with computational reconstruction techniques.
• Deriving necessary conditions for a broadband, 1 cm aperture, f/2 flat optic with specific field of view and modulation transfer function (MTF) requirements.
• Utilizing a coaxial, dual-aperture system to train the meta-optic with a learned reconstruction method.

Main Results:

• Demonstration of broadband imaging in the visible wavelength range with a single flat meta-optic.
• Achieved system performance metrics including a 30° field of view and average system MTF contrast of >=20% at 100 lp/mm (>=30% at <70 lp/mm).
• Successfully trained the meta-optic using a learned reconstruction method on pair-wise captured imaging data.

Conclusions:

• The developed flat meta-optic overcomes fundamental chromatic aberration limitations, enabling high-quality broadband imaging.
• This work presents a viable approach for achieving full-color imaging with a single, large-aperture meta-optic, previously considered unattainable.
• The co-design of meta-optics and computational reconstruction offers a powerful strategy for advancing flat optics technology.