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Using interference in the frequency domain for precise determination of thickness and refractive indices of normal dispersive materials

1995; Optica Publishing Group; Volume: 12; Issue: 9 Linguagem: Inglês

10.1364/josab.12.001559

1520-8540

Vinay Kumar, D. Narayana Rao,

Advanced Fluorescence Microscopy Techniques

We present an experimental demonstration of the spectral interference phenomenon, using a spectrally broad white-light source in a Michelson interferometer configuration. We also present a theoretical analysis of the spectral interference law for the general case of amplitude-division interferometers. When a dispersive medium is introduced into one of the arms of the interferometer, the spectral interference pattern changes drastically, with a change in the frequency modulation corresponding to the dispersive nature of the medium. A zero-order fringe appears at a wavelength where the net path difference between the two arms of the interferometer is zero. We relate the thickness of the dispersive medium to the width of the zero-order fringe. From the experimental data over the entire visible region of the spectrum we obtain the refractive index n(λ) and the thickness t of the dispersive medium, calculated to an accuracy of the order of 10−5.