Differential interferometers creating desired beam patterns

An interferometer, comprising:

• an optical stack comprising:
• a first prism comprising a vertical face and a first angled face;
• a second prism comprising a second angled face and a third angled face, wherein:
• the first prism is mounted to the second prism by fixing the first angled face to the second angled face;
• a lower portion of a first interface between the first and the second angled faces comprises a first polarizing beam-splitter (PBS);
• a third prism comprising a fourth angled face and a fifth angled face, wherein:
• the second prism is mounted to the third prism by fixing the third angled face to the fourth angled face;
• a second interface between the third and the fourth angled faces comprises at least a second PBS;
• the fifth angled face comprises a first mirror;
• a first wave plate element, a second wave plate element, a third wave plate element, and a fourth wave plate element located in beam paths between the optical stack and at least one of a measurement optic and a reference optic;
• a redirecting optic mounted at least adjacent to the vertical face.

An interferometer, comprising:

• a shear plate comprising:
• a first face comprising:
• an input port;
• a first mirror adjacent to the input port;
• an output port adjacent to the first mirror;
• and
• a second mirror adjacent to the output port;
• a second face parallel to the first face, the second face comprising:
• a first polarizing beam-splitter (PBS) opposite the input port along a first direction and opposite the first mirror along a second direction;
• a first intermediate port adjacent to the first PBS and opposite the first mirror along the first direction;
• a second PBS adjacent to the first intermediate port and opposite the output port along the first direction and opposite the second mirror along the second direction;
• a second intermediate port adjacent to the second PBS and opposite the second mirror along the first direction;
• a first wave plate opposite the first PBS in a first beam path between the first PBS and a first optic along third direction;
• a second wave plate opposite the first intermediate port in a second beam path between the first intermediate port and a second optic along the third direction;
• a third wave plate opposite the second PBS in a third beam path between the second PBS and the second optic along the third direction;
• a fourth wave plate opposite the second intermediate port in a fourth beam path between the second intermediate port and the first optic along the third direction;
• and
• a redirecting optic opposite the first and the second PBSs in a beam path along a fourth direction.

An interferometer system, comprising:

• a first prism, comprising a first vertical face, a first angled face, a second vertical face, a second angled face, wherein the second angled face comprises a mirror for reflecting light between a first direction and a second direction orthogonal to the first direction;
• a second prism comprising a horizontal face, a third vertical face, and a third angled face, wherein:
• the second prism is mounted to the first prism by fixing the third angled face to the first angled face;
• an interface between the first and the third angled faces comprises a polarizing beam-splitter (PBS) opposite the mirror for transmitting light along one of the first and the second directions, and reflecting light between the first and the second directions;
• a first wave plate element and a second wave plate element mounted at least adjacent to the second vertical face opposite the mirror in a first plurality of beam paths between the mirror and at least one of a measurement optic and a reference optic;
• a third wave plate element and a fourth wave plate element mounted at least adjacent to the third vertical face opposite the PBS in second plurality of beam paths between the PBS and at least one of the measurement optic and the reference optic;
• and
• a redirecting optic mounted at least adjacent to the horizontal face of the second prism, the redirecting optic returning light in a parallel path offset along a third direction orthogonal to the first and the second directions.

An interferometer system, comprising:

• a shear plate, comprising:
• a first angled face, comprising:
• an input port;
• an output port adjacent to the input port;
• a first mirror element;
• a second mirror element adjacent to the output port;
• a second angled face parallel to the first angled face, the second angled face comprising:
• a first PBS element opposite the input port along a first direction and opposite the first mirror along a second direction;
• a second PBS element opposite the output port along the first direction and opposite the second mirror along the second direction;
• a first intermediate port opposite the first mirror along the first direction;
• a second intermediate port opposite the second mirror along the first direction;
• a first wave plate element opposite the first PBS element in a first beam path between the first PBS element and a first optic along a third direction;
• a second wave plate element opposite the second PBS element in a second beam path between the second PBS element and a second optic along the third direction;
• a third wave plate element opposite the first intermediate port in a third beam path between the first intermediate port and the second optic along the third direction;
• a fourth wave plate element opposite the second intermediate port in a fourth beam path between the second intermediate port and the first optic along the third direction;
• and
• a redirecting optic opposite the first and the second PBSs in a fifth beam paths along a fourth direction.