The novel depth-sensing system presented here revolutionizes
structured
light (SL) 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 (FOV) of 158° and a 0.611° dot sampling angle,
the system is lens-free and lightweight and boasts lower power consumption
than vertical-cavity surface-emitting laser (VCSEL) 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 SL depth-sensing but
also opens avenues for compact integration into wearable devices,
offering remarkable advantages in size, power efficiency, and potential
for widespread adoption.