A Zeeman-split laser line near nm consists of two components separated in frequency by GHz
PHYSICS · Subjective · Fermi University Physics · Optics & Photonics · Interference and diffraction · Interference and diffraction
Optics and Photonics, Ch Multiple-beam interference: thin films, multilayers and the Fabry-Perot etalon
Problem
A Zeeman-split laser line near λ=632.8 nm consists of two components separated in frequency by Δν=5.0 GHz. A pair of flat, parallel, lossless mirrors of power reflectance R=0.92 is available, and may be set facing each other in air (n=1) at any spacing d, forming a Fabry-Perot etalon at normal incidence. (a) Choose a spacing d so that the etalon's half-width Δν1/2 is one quarter of the line separation, a comfortable margin for telling the two components apart. (b) Check that the two components lie well within a single free spectral range, so that neighbouring orders are not confused. (c) State the resulting free spectral range, linewidth, interference order and resolving power at 632.8 nm.