| 摘要 |
Incoming light is reflected and bent through 90 deg. from its original direction by a flat mirror. The light then comes in contact with a focussing mirror in a direction which coincides with that normal for the centre of the curved, mirroring surface. The distance between the two mirrors is selected so that the focus of the focussing mirror coincides with the centre of the flat, mirroring surface. At this point, a hole is drilled through the flat mirror at an angle of 45 deg. This permits the end of a fibre or a detector to be positioned in focus. The arrangement may be used in a reversed manner, i.e a divergent light source is placed in the hole, whereby the emitted light remains parallel. The distance between the mirrors may be varied by one mirror being rotated relatively to the other around an axis coinciding with that of the hole. |
