Object tracking system including polarization selective optical element

An optical element, comprising:

• a primary birefringent medium layer having a first birefringence;
• and
• two or more secondary birefringent medium layers stacked with the primary birefringent medium layer and distributed at both sides of the primary birefringent medium layer, the two or more secondary birefringent medium layers having two or more birefringences,
• wherein the primary birefringent medium layer and the two or more secondary birefringent medium layers include birefringent materials having chiralities, and
• wherein the first birefringence is greater than the two or more birefringences.

A system, comprising:

• a light source configured to emit a light to illuminate an object, the light being reflected by the object;
• a polarization selective optical element configured to diffract the light reflected by the object into a plurality of signal lights;
• and
• at least one optical sensor configured to receive the signal lights and generate a plurality of tracking signals for tracking the object,
• wherein the at least one optical sensor includes at least two optical sensors configured to receive at least two of the plurality of signal lights with orthogonal polarizations, respectively.