Coherent Multilayer Photonic Nanoantenna Array with off-Aperture Phase Adjustment

Two-dimensional optical beam-steering with applications in LiDAR, projection, imaging, and communication is performed using either a 2-D optical phased array (OPA) with per-element optical phase control or a 1-D OPA with a combination of phase control and wavelength tuning. The former typically suffers from a high power consumption and a large element-spacing, and the latter requires a highly tunable laser and is incompatible with certain 2-D beam-steering applications such as communication. In either case, achieving subwavelength element-spacing is challenging due to the large size of devices compared to the operation wavelength. Here, we report a single-wavelength multilayer 2-D OPA, where a beam is formed through near-field interference of waves emitted from array elements on each layer. Vertically aligned tilted optical nanoantennas, 3-D optical signal distribution, and off-aperture phase control enable the realization of a record element-pitch of 3 mu m. The 64-element 2-D OPA achieves a steering range of 23 degrees using only 16 phase shifters.

Automated summary

A novel multilayer 2-D optical phased array technology is introduced in this study, achieving a record element-pitch and a wide steering range through special designs.