Retardation line for an interferometer.

摘要

The delay line includes a guided path (2) and an optical load (3) with a graduated scale (4). The guided path stretches out a given distance along a predetermined direction. The load is carried by a computer (14) controlled trolley (6) along the path. A series of optical readers (5A,5B,5C) are located along the guided path adjacent to the high accuracy scale on the optical load. Actuators on the trolley and optical load (8,11) are controlled by loops fed from an accelerometer (9) and position indicator (10) to minimise vibration. Electronic and numerical logic units (13, 14) ensure that successive optical readers are switched in and read as the optical load passes.