Question

8. A Fabry-Perot interferometer consists of two mirrors, each with a reflection coefficient R of 0.95, that are separated by a distance d in air. The transmission property of the interferometer is described by the Airy's formula, which is given by I-sin 1+Fsin) Here, is the transmitted light intensity due to an input light intensity of . F is the coefficient of finesse that is given by F#-A-, and is the phase difference between (1-R) successive reflections. The interferometer is used to resolve the two components of the H-alpha doublet of the hydrogen spectrum, whose wavelength separation is 0.136 4 at 6563 4, at normal incidence. Find the minimum distance d required for the separation of the mirrors in order to achieve the required resolution. 10 marks)

Answer 1

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