Common-path cube corner interferometer and interference technique

A common-path cube corner interferometer, comprising:

• a semi-transmissive and semi-reflective beam splitter, a plane mirror, a first right-angled cube-corner retroreflector, a second right-angled cube-corner retroreflector and an optical path difference element;
• wherein:
• the semi-transmissive and semi-reflective beam splitter splits incident light into a first transmitted beam and a second reflected beam;
• the plane mirror is vertically arranged relative to the semi-transmissive and semi-reflective beam splitter;
• the first right-angled cube-corner retroreflector and the second right-angled cube-corner retroreflector are asymmetrically arranged at either side of the semi-transmissive and semi-reflective beam splitter, and a base plane of the first right-angled cube-corner retroreflector is parallel to an incident direction of the incident light, while a base plane of the second right-angled cube-corner retroreflector is perpendicular to the incident direction of the incident light;
• the first beam is sequentially reflected by the plane mirror, the first right-angled cube-corner retroreflector, the plane mirror, the second right-angled cube-corner retroreflector, the plane mirror, and then returns to the semi-transmissive and semi-reflective beam splitter for splitting into the first transmitted beam and the first reflected beam;
• the second beam is sequentially reflected by the plane mirror, the second right-angled cube-corner retroreflector, the plane mirror, the first right-angled cube-corner retroreflector, the plane mirror, and then returns to the semi-transmissive and semi-reflective beam splitter for splitting into the second reflected beam and the second transmitted beam;
• the first reflected beam and the second transmitted beam are parallel to the incident light;
• and
• the optical path difference element is arranged at a random position in an optical path where the second beam is reflected by and then returns to the semi-transmissive and semi-reflective beam splitter, or at a random position in an optical path where the first beam is transmitted by and then returns to the semi-transmissive and semi-reflective beam splitter, so that an optical path difference is generated between the first beam and the second beam.