Randomized metalens array homogenizer for enhanced laser beam shaping.

We present a beam homogenizer utilizing on a random metalens array (RMA) for enhanced beam shaping. The RMA, comprising 28 × 28 individual metalenses with random sizes, is designed using an improved Gerchberg-Saxton algorithm. As a laser beam traverses the RMA, it is divided into 28 × 28 beams, each exhibiting a unique speckle pattern.

Wide-angle and high-efficiency flat retroreflector.

We propose a flat retroreflector that can efficiently reflect the electromagnetic waves back along its incident direction in a wide continuous range of angles. This retroreflector consists of a quadratic metalens and a flat metallic reflector at the focal plane of the former. The quadratic metalens is a dielectric pillar array encoded with a quadratic phase profile and it is embedded in the top side of the substrate.

High-efficiency one-dimensional metalens for 3D focusing.

We demonstrate a high-efficiency on-chip one-dimensional metalens for three-dimensional (3D) light focusing. The metalens consists of a one-dimensional dielectric nano-antenna array, which scatters the evanescent wave of a nano-waveguide into free space and focuses this scattered light into a 3D ring. The corresponding phase profile of the metalens is controlled by the relative locations of antennas in the array.