| 摘要 |
A method and apparatus for studying a surface using an interferometer, in which there is relative motion between the surface and the interferometer, the motion having a total velocity Vtot which includes a transversal component Vt and a longitudinal component V1. For example the invention can be applied to measuring a surface which is subject to vibration such as a window pane. It is also applicable to the measurement of movement of the earth's surface for seismic exploration. An array of detectors is arranged on the interferometer in a line extending generally in the transversal direction, the detectors being arranged to detect light rays with different angular directions, representing different sensitivity directions. A reference beam is combined with a reflected object beam from the surface to produce a cross interference in the speckle pattern providing information about the relative motion of the surface and the interferometer. The temporal change in which of the detectors has zero or minimum sensitivity to the total velocity is monitored. Temporal changes in the direction of the motion Vtot are detected and hence temporal changes in the longitudinal velocity component V1 are determined. |
