Abstract: A system is provided. The system includes a light source configured to emit a infrared (“IR”) light for illuminating an object. The system also includes a waveguide imaging assembly including a waveguide, an in-coupling element disposed at a first portion of the waveguide, an out-coupling element disposed at a second portion of the waveguide, and an optical sensor disposed facing the out-coupling element. The in-coupling element is configured to couple the IR light reflected by the object into the waveguide, the waveguide is configured to guide the IR light to propagate toward the out-coupling element through total internal reflection, and the out-coupling element is configured to couple the IR light out of the waveguide toward the optical sensor. The optical sensor is configured to generate a tracking signal of the object based on the IR light output from the waveguide.