Spectrally Resolved White Light Interferometry for Simultaneous Measurement of the Refractive Index and Thickness

Study of the interference effects in the space-frequency domain is substantially different from the study in the space-time domain though the basic equations are similar in their form. Recently, there is been an increasing interest in the theoretical and experimental investigations of number of coherence phenomena in the spacefrequency domain [1,2]. As has already been amply discussed and demonstrated in the earlier chapters of this thesis, the interference between two amplitude or wavefront divided beams occur irrespective of the path delay between the interfering beams. The effect is manifested as periodic spatial variation of intensity or as spectral variations depending on whether the path difference between them is less or more than the coherence length of the source respectively [3-8]. The spectral interference phenomenon giving rise to spectral modulations for different degrees of correlation between the interfering beams has been studied theoretically [7,9] and verified experimentally[8,10]. The periodicity and characteristics of these spectral fringes depend on the way the interfering beams are correlated and on the bandwidth of the source used.