Wave front shearing interferometer

Claim 1

A WAVE FRONT SHEARING INTERFEROMETER COMPRISING: A PAIR OF PRISMS, EACH PRISM HAVING AN ENTRANCE FACE, A COMMON FACE, A REFLECTING FACE, AND AN EXIT FACE, THE COMMON FACE OF EACH PRISM FORMING FIRST, SECOND AND THIRD DIHEDRAL ANGLES WITH THE REFLECTING, ENTRANCE AND EXIT FACES, RESPECTIVELY, OF SAID PRISM, THE VERTEX LINE OF SAID FIRST DIHEDRAL ANGLE BEING CLOSER TO THE VERTEX LINE OF SAID THIRD DIHEDRAL ANGLE, IN TO THE VERTEX LINE OF SAID SECOND DIHEDRAL ANGLE, IN EACH OF SAID PRISMS, A SEMIREFLECTING FILM SAID PRISMS BEING DISPOSED ADJACENT EACH OTHER WITH SAID SEMIREFLECTING FILM ENCLOSED BETWEEN SAID COMMON FACES, THE APICES OF THE FIRST DIHEDRAL ANGLE OF SAID ADJACENT PRISMS POINTING IN THE SAME DIRECTION, SAID FIRST, SECOND AND THIRD DIHEDRAL ANGLES BEING SELECTED SO THAT A RAY OF LIGHT ENTERING ONE OF SAID ENTRANCE FACES IS DIVIDED AT A FIRST REGION OF SAID SEMIREFLECTING FILM INTO RANSMITTED AND REFLECTED COMPONENTS WHICH ARE REFLECTED BY SAID REFLECTING FACES BACK TO SAID SEMIREFLECTING FILM AT A SECOND REGION THEREOF WHICH IS DIFFERENT FROM SAID FIRST REGION, EACH OF SAID COMPONENTS DIVIDING AT SAID SECOND REGION INTO FURTHER COMPONENTS THAT EXIT IN PAIRS THROUGH SAID EXIT FACES, THE REFLECTING FACES OF SAID PRISMS EACH BEING INCLINED WITH RESPECT TO SAID SEMIREFLECTING FILM SO AS TO CAUSE THE WAVE FRONTS ASSOCIATED WITH EACH PAIR OF EXITING COMPONENTS TO BE SHEARED RELATIVE TO EACH OTHER.