| 摘要 |
<p>A polarising interferometer wherein at least one of the two measuring arms (13,14) contains an optical cube corner (16 or 19) devoid of coatings on its reflecting surfaces and with its refractive index selected so that the resulting retardation and orientation of the principal axes causes the cube corner to act as a lambda /4 plate, the beam through the uncoated cube corner being reflected back through a movable end reflector (18 or 20) insensitive to tilt and lateral movement so that the uncoated cube corner acts as a lambda /2 plate on double transmission, and phase difference in the output beams is detected by an analyser (23, 26, 28) forming four spatially separated component beams respectively polarised at differing azimuth angles, which give two outputs in phase quadrature, of equal amplitude and free of d.c. offsets. The uncoated cube corner acting as a lambda /4 plate on single transmission and a lambda /2 plate on double transmission also has application to other polarising optical systems, especially where a coated cube corner has hitherto been used.</p> |
