Optical element, measuring apparatus and measuring method

A measuring apparatus, the measuring apparatus configured to transmit an optical beam towards an object in a transmission direction through the optical element, and to receive an optical beam reflected from the object in a reception direction through the optical element, wherein the optical element comprises:

• a beam transformer having an entrance aperture of the transmission direction, a common two-directional aperture for an exit in the transmission direction and for an entrance in the reception direction, and an exit aperture of the reception direction, and the beam transformer is configured to form at least two internal optical channels supporting different plane-polarization directions, the internal optical channels being common to the transmission and reception direction,
• at least two non-reciprocal components for propagation-direction-dependent polarization operations, and in the transmission direction,
• the beam transformer is configured to split the optical beam input through the entrance aperture of the transmission direction into plane-polarized beams and to pass the plane-polarized beams to the optical channels,
• the at least two non-reciprocal components, one for each plane polarized beam in the optical channels, are configured to perform a first propagation-direction-dependent operation on the plane-polarized beams,
• the beam transformer is configured to combine the optical beams from the optical channels into a transmission beam and to transmit the transmission beam through the common aperture;
• and in the reception direction,
• the beam transformer is configured to split the optical beam received through the common aperture into plane-polarized beams and to pass the plane-polarized beams to the optical channels,
• each non-reciprocal component is configured to perform a second propagation-direction-dependent operation on the plane-polarized beams in the optical channels, and
• the beam transformer is configured to combine the plane-polarized beams from the optical channels into one received optical beam, and to output the received optical beam through the exit aperture of the reception direction different from the entrance aperture of the transmission direction due to propagation-direction-dependent operations in the optical channels.

A measuring method, the method comprising:

• transmitting, by a measuring apparatus, an optical beam towards an object in a transmission direction through the optical element wherein the transmitting comprises
• splitting the optical beam input through the entrance aperture of transmission direction into plane-polarized beams, and passing the plane-polarized beams to internal optical channels by the beam transformer, the internal optical channels being common to the transmission and the reception directions,
• performing a first propagation-direction-dependent operation on the optical beam by at least two non-reciprocal component, one in each optical channel
• combining optical beams from the optical channels into a transmission beam and transmitting the transmission beam through the common aperture, by the beam transformer;
• receiving, by the measuring apparatus, an optical beam reflected from the object in a reception direction through the optical element, wherein the receiving comprises;
• splitting the optical beam received through the common aperture into plane-polarized beams, and passing the plane-polarized beams to the optical channels by the beam transformer,
• performing a second propagation-direction-dependent operation on the plane-polarized beams in the optical channels by each non-reciprocal component,
• combining the plane-polarized beams from the optical channels into one received beam, and outputting the received beam through the exit aperture of the reception direction by the beam transformer, the exit aperture of the reception direction being different from the entrance aperture of the transmission direction due to propagation-direction-dependent operations in the optical channels.