Cadmium red light has a mean wavelength of λ̅₀= 643.847 nm (see Fig. 7.45) and a linewidth of 0.001 3 nm. When used to illuminate a Michelson Interferometer it is found that increasing the mirror separation from zero to some amount D causes the fringes to vanish. Show that

and then determine D for the cadmium line.

 Fig. 7.45

Transcribed Image Text:

Δλο ΔΙ Imax Imax A (nm) --0.002 –0.001 +0.001 +0.002 643.847 +0.000 65 nm at Imax/2