Programmable Structured Light Using Metasurface Optics and Individually Addressable VCSEL Array

Structured-light based 3D sensing technology has been widely used in machine vision, face recognition, and unmanned driving due to high spatial resolution, miniaturized size, large field of view (FOV), and strong anti-interference capability. Speckle structured light is one kind of structure light method. For speckle structured light, certain designed structured projected dot pattern is usually generated by fixed random patterned vertical-cavity surface-emitting laser (VCSEL) array beam duplicated by diffraction optical elements (DOE). This method is conventionally static and non-programmable, resulting in low flexibility. In this paper, a novel programmable structured light is implemented by combining a silicon-on-insulator (SOI) reflective metasurface and an individually addressable vertical-cavity surface-emitting laser (VCSEL) array chip. The designed individually addressable VCSEL array is composed of 8 by 8 VCSELs with 100um pitch. These VCSELs share the same cathode, but anodes are separated for on-off switching. The SOI consists of a 3um intermediate SiO2 layer and 340nm Si top layer. Si nanorods are formed by etching the Si top layer. The dimension and rotation of the nanorods are carefully designed so that different VCSEL from the VCSEL array creates speckle pattern with steerable position. By coding the VCSEL on-off states in the VCSEL array, programmable structured light and dynamic speckle density adjustment is achieved. We experimentally demonstrated the new method can get micron level precision which is much better than conventional method. Moreover, great potential is also found for eye movement tracking with the new method. Prototype model for AR/VR glasses application is proposed.