Đo lường quang học P3

Interference The superposition principle for electromagnetic waves implies that, for example, two overlapping fields u1 and u2 add to give u1 + u2 . This is the basis for interference. Because of the slow response of practical detectors, interference phenomena are also a matter of averaging over time and space. Therefore the concept of coherence is intimately related to interference. In this chapter we will investigate both topics. A high degree of coherence is obtained from lasers, which therefore have been widely used as light sources in interferometry. In recent years, lack of coherence has been taken to advantage in a...