Azimuthally segmented achromatic binary flat lenses with extended depth of focus

Lenses are ubiquitous elements in any optical system. With technological advances and the widespread use of optical systems in fields such as optical communication, medical imaging, computer vision, optical sensing, the creation of optical elements that are smaller, lighter, and reliable over a broad-spectrum is of key interest. Flat and meta lenses try to answer the demand for such solutions. However, these structures are known for being highly wavelength-dependent due to their diffraction-based operation. In this work, we present a set of binary phase Fresnel zone plates with an azimuthally segmented design to provide polychromatic or continuous achromatic focusing over the visible spectrum. The focusing efficiency and the imaging properties of the lenses are analyzed both experimentally and through simulation via scalar diffraction theory, demonstrating their potential for broad-spectrum applications. We also evaluate the extended depth of focus obtained for the achromatic lens, achieving a range of 10 mm where the probing spectral region is efficiently focused.