INTERFEROMETER
Fabry Pérot Interferometer Maurice Paul Auguste Charles Fabry (1867-1945) Alfred Pérot (1863-1925)
Michelson Fringes Fabry Perot Fringes
Fabry-Perot Interferometer S2 S1
T+R+A=1 T: Transmittance (tt) R : Reflectance (r2) A: Absorbance
Irradiance d: successive phase difference of the transmitted rays
A A (q) : Airy’s function A
Measurement of sharpness of fringes
Finesse F of the mirror system is defined by
Chromatic Resolving power
Fabry-Perot Interferometer θ o 30
I0
IR/I IT/I φ
Transmitted intensity
d/λ = 10 , f = 8 d/λ = 10 , f = 1 θ θ d/λ = 1000 , f = 7 o θ 30 θ d/λ = 1000 , f = 7 d/λ = 10 , f = 2 θ θ o 3
Michelson fringes Fabry-Perot fringes
Full width at half maximum
Resolved wavelengths
Unresolved wavelengths
Barely resolved
Chromatic resolving power of Fabry Perot interferometer
Doublet separation in Fabry-Perot interferometer
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λ1= 589.0 nm λ2= 589.6 nm Δλ= 0.6 nm λ/Δλ~1000 CRP<1000 Sodium doublet λ1= 589.0 nm λ2= 589.6 nm Δλ= 0.6 nm λ/Δλ~1000 CRP<1000
λ1= 589.0 nm λ2= 589.6 nm Δλ= 0.6 nm λ/Δλ~1000 CRP ~ 1000 Sodium doublet λ1= 589.0 nm λ2= 589.6 nm Δλ= 0.6 nm λ/Δλ~1000 CRP ~ 1000
λ1= 589.0 nm λ2= 589.6 nm Δλ= 0.6 nm λ/Δλ~1000 CRP >1000 Sodium doublet λ1= 589.0 nm λ2= 589.6 nm Δλ= 0.6 nm λ/Δλ~1000 CRP >1000
λ1= 589.0 nm λ2= 589.6 nm Δλ= 0.6 nm λ/Δλ~1000 CRP >> 1000 Sodium doublet λ1= 589.0 nm λ2= 589.6 nm Δλ= 0.6 nm λ/Δλ~1000 CRP >> 1000
λ1= 589.0 nm λ2= 589.6 nm Δλ= 0.6 nm λ/Δλ~1000 CRP>>>1000 Sodium doublet λ1= 589.0 nm λ2= 589.6 nm Δλ= 0.6 nm λ/Δλ~1000 CRP>>>1000