Increasing the Field-of-View Radiation Efficiency of Optical Phased Antenna Arrays

TL;DR

This paper presents a silicon-based optical phased array with nanoantennas achieving high radiation efficiency and a wide field of view, suitable for applications like LiDAR and holography.

Contribution

The work introduces a large-scale 2D silicon optical phased array with optimized nanoantennas for high efficiency and wide field of view, demonstrating potential for complex wavefront generation.

Findings

Radiation efficiency up to 90% at 1.55μm wavelength

6.8% of optical power concentrated in the field of view

Potential for fabrication and complex holographic imaging

Abstract

Silicon photonics in conjunction with complementary metal-oxide-semiconductor (CMOS) fabrication has greatly enhanced the development of integrated optical phased arrays. This facilitates a dynamic control of light in a compact form factor that enables the synthesis of arbitrary complex wavefronts in the infrared spectrum. We numerically demonstrate a large-scale two dimensional silicon-based optical phased array (OPA) composed of nanoantennas with circular gratings that are balanced in power and aligned in phase, required for producing elegant radiation patterns in the far field. For a wavelength of 1.55$\mu m$, we optmize two antennas for the OPA exhibting an upward radiation efficiency as high as 90%, with almost 6.8% of optical power concentrated in the field of view. Additionally, we believe that the proposed OPAs can be easily fabricated and would have the ability of generating complex holographic images, rendering them an attractive candidate for a wide range of applications like LiDAR sensors, optical trapping, optogenetic stimulation and augmented-reality displays.