We develop a novel depth-sensing system revolutionizing structured light technology by employing metasurfaces and photonic crystal surface-emitting lasers (PCSELs) for efficient facial recognition in monocular depth-sensing. Unlike conventional dot projectors relying on diffractive optical elements (DOEs) and collimators, our system projects approximately 45,700 infrared dots from a compact 297-μm-dimention metasurface, drastically more spots (1.43 times) and smaller (233 times) than the DOE-based dot projector in an iPhone. With a measured field-of-view of 158° (~2 times wider) and a 0.611° dot sampling angle, the system is lens-free, lightweight, and boasts lower power consumption than vertical-cavity surface-emitting laser arrays, resulting in a 5-10 times reduction in power. Utilizing a GaAs-based metasurface and a simplified optical architecture, this innovation not only addresses the drawbacks of traditional structured-light depth-sensing but also opens avenues for compact integration into wearable devices, offering remarkable advantages in size, power efficiency, and potential for wide-spread adoption.
It is published in Nano Letters.
我們發展創新的深度感測與臉部偵測系統。在此研究，我們採用超穎介面和光子晶體面射型雷射，在單眼深度感測中實現了結構光技術的革命性升級，以實現高效的臉部識別。與依賴繞射光學元件和準直鏡的傳統點陣投影儀不同，我們的系統從一個超微小的 297 微米尺寸的超穎介面投射約 45,700 個紅外光束，比 iPhone Face ID上基於繞射光學元件的點陣投影儀的點數多（1.43 倍）且面積更小（233 倍）、更寬的視場 158°（~2 倍）。該系統無需鏡頭，重量輕，且比目前商用的垂直共振腔面射型雷射陣列具有更低的功耗，功耗減少 5-10 倍。經由使用基於砷化鎵的超穎介面和簡化的光學結構，這種創新不僅解決了傳統結構光深度感測的缺點，還為其在可穿戴設備中的超微小積體化感測器開闢了新的可能性，提供了卓越的尺寸、功耗效率和廣泛應用潛力的優勢。
