INTERFEROMETER Fabry Prot Interferometer Maurice Paul Auguste Charles

INTERFEROMETER

Fabry Pérot Interferometer Maurice Paul Auguste Charles Fabry (1867 -1945) Alfred Pérot (1863 -1925)

Michelson Fringes Fabry Perot Fringes

Fabry-Perot Interferometer S 2 S 1

T+R+A=1 T: Transmittance (tt ) R : Reflectance (r 2) A: Absorbance

Irradiance d: successive phase difference of the transmitted rays

A A (q) : Airy’s function A

Measurement of sharpness of fringes g

Finesse F of the mirror system is defined by

Chromatic Resolving power

Fabry-Perot Interferometer θ 30 o

I 0

IR/I IT/I φ

Transmitted intensity

Fabry-Perot fringes Michelson fringes

Full width at half maximum φm

Resolved wavelengths

Unresolved wavelengths

Barely resolved

Chromatic resolving power of Fabry Perot interferometer

Doublet separation in Fabry-Perot interferometer

Sodium doublet λ 1= 589. 0 nm λ 2= 589. 6 nm Δλ= 0. 6 nm λ/Δλ~1000 CRP<1000

Sodium doublet λ 1= 589. 0 nm λ 2= 589. 6 nm Δλ= 0. 6 nm λ/Δλ~1000 CRP ~ 1000

Sodium doublet λ 1= 589. 0 nm λ 2= 589. 6 nm Δλ= 0. 6 nm λ/Δλ~1000 CRP >1000

Sodium doublet λ 1= 589. 0 nm λ 2= 589. 6 nm Δλ= 0. 6 nm λ/Δλ~1000 CRP >> 1000

Sodium doublet λ 1= 589. 0 nm λ 2= 589. 6 nm Δλ= 0. 6 nm λ/Δλ~1000 CRP>>>1000