Mirror with polarizing beam splitter for LIDAR system

A reflective apparatus for an optical system, comprising:

• a planar structure having a first surface and a substantially parallel second surface, the planar structure defining an aperture, wherein the aperture extends from the first surface to the second surface and is in a first path of a first light pulse;
• and
• a polarizing beam splitter disposed in the aperture, the polarizing beam splitter configured to pass a portion of the first light pulse,
• wherein the first surface includes a reflective surface configured to reflect a second light pulse in a second path, the second light pulse including a return pulse based on the first light pulse being reflected from an object,
• wherein the second surface includes an anti-reflection layer,
• wherein a size of the polarizing beam splitter is smaller than a size of the reflective surface,
• wherein a shape of the planar structure has a circular shape,
• wherein a shape of the aperture is different from the shape of the planar structure, and
• wherein at least one of the polarizing beam splitter and the anti-reflection layer is a coating on a base layer of the reflective element.

A method comprising;

• emitting, by an emitter, a first light pulse in a first path;
• transmitting, by a polarizing beam splitter in the first path and aligned with an aperture of a reflective element, a portion of the first light pulse, wherein the reflective element is disposed of in the first path;
• reflecting, by a reflective surface of the reflective element, a second light pulse in a second path, the second light pulse including a return pulse based on the first light pulse being reflected from an object, wherein a size of the polarizing beam splitter is smaller than a size of the reflective surface;
• detecting, by a detector, the second light pulse, the detector disposed in the second path of the second light pulse;
• and
• providing an anti-reflection layer opposite the reflective surface,
• wherein a shape of the reflective element has a circular shape,
• wherein a shape of the aperture is different from the shape of the reflective element, and
• wherein at least one of the polarizing beam splitter and the anti-reflection layer is a coating on a base layer of the reflective element.