Light Sources and Detectors
The most important ‘hardware’ in optical metrology is light sources and detectors. To appreciate the various concepts of these devices, we ﬁrst introduce the different units and terms for the measurement of electromagnetic radiation. Then the laser is given a relatively comprehensive treatment. The description of detectors involves some understanding of semiconductor technology. Therefore a brief introduction to semiconductors is given in Appendix E. Because of the increasing use of the CCD camera in optical metrology, this device is described separately in Section 5.8.