Optical sensor

An optical sensor, comprising:

• at least one pair comprising a radiation source and a corresponding radiation receiver;
• and
• an optical circuit including a collimating element, a first optical element, and a second optical element,
• wherein the collimating element is configured to collimate radiation from the radiation source,
• wherein the first optical element and the second optical element are interconnected by a common surface, the common surface being a semitransparent surface,
• wherein the first optical element comprises:
• an input/output surface for:
• inputting radiation from the radiation source and directing to the semitransparent surface, wherein the semitransparent surface is configured to divide the radiation input through the input/output surface into reference radiation and working radiation, and
• emitting the reference radiation and the radiation reflected from an object or scattered by the object to the radiation receiver, and
• a reflective surface of the first optical element for directing the reference radiation reflected from the semitransparent surface and the radiation reflected from the object or scattered by the object to the input/output surface for emitting from the optical circuit to the radiation receiver,
• wherein the second optical element comprises:
• a working surface for emitting the working radiation that has passed through the semitransparent surface and receiving the radiation reflected from the object or scattered by the object, and
• a reflective surface for directing radiation reflected from the object or scattered by the object through the semitransparent surface to the reflective surface of the first optical element,
• wherein all radiation sources and radiation receivers are located in a same plane,
• wherein a quarter-wave plate embedded in the input surface of the first optical element, and
• wherein the radiation source comprises a laser with a fixed polarization.