Óptica Moderna Fundamentos e aplicações - Fotonica.ifsc.usp.br ...
Óptica Moderna Fundamentos e aplicações - Fotonica.ifsc.usp.br ...
Óptica Moderna Fundamentos e aplicações - Fotonica.ifsc.usp.br ...
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
136<<strong>br</strong> />
Usando a lei de Snell, k1 sen θ<<strong>br</strong> />
2k<<strong>br</strong> />
2d<<strong>br</strong> />
δ = φ<<strong>br</strong> />
θ ′ ′<<strong>br</strong> />
2−<<strong>br</strong> />
φ1<<strong>br</strong> />
= − 2k1d<<strong>br</strong> />
sen θ tg<<strong>br</strong> />
cosθ<<strong>br</strong> />
′ ′<<strong>br</strong> />
2d<<strong>br</strong> />
= { k − k sen θsen<<strong>br</strong> />
θ ′ ′<<strong>br</strong> />
2 1 }<<strong>br</strong> />
cosθ<<strong>br</strong> />
′ ′<<strong>br</strong> />
= k sen θ ′ ′<<strong>br</strong> />
2 , temos:<<strong>br</strong> />
4π<<strong>br</strong> />
δ = 2dk cosθ<<strong>br</strong> />
′ ′ = n d cosθ<<strong>br</strong> />
′ ′<<strong>br</strong> />
2<<strong>br</strong> />
λ<<strong>br</strong> />
Interferência<<strong>br</strong> />
(6.37)<<strong>br</strong> />
(6.38)<<strong>br</strong> />
2<<strong>br</strong> />
0<<strong>br</strong> />
As condições de máximo e mínimo de interferência são dadas<<strong>br</strong> />
respectivamente por:<<strong>br</strong> />
4πn<<strong>br</strong> />
λ<<strong>br</strong> />
0<<strong>br</strong> />
d cos θ ′ ′ = ( 2m<<strong>br</strong> />
+ 1 π<<strong>br</strong> />
2 ) (6.39a)<<strong>br</strong> />
4πn<<strong>br</strong> />
λ<<strong>br</strong> />
0<<strong>br</strong> />
d cos θ ′ ′ = 2mπ<<strong>br</strong> />
2 (6.39b)<<strong>br</strong> />
6.4 Interferômetro de Fa<strong>br</strong>y-Pérot<<strong>br</strong> />
Voltamos agora à discussão da interferência de múltiplos feixes<<strong>br</strong> />
considerando todos os feixes emergindo da placa como indicado na Fig.<<strong>br</strong> />
6.12. Usando o princípio da superposição encontramos o campo elétrico<<strong>br</strong> />
transmitido como:<<strong>br</strong> />
E =<<strong>br</strong> />
E0<<strong>br</strong> />
E1’<<strong>br</strong> />
E1<<strong>br</strong> />
E2’ E3’ E4’<<strong>br</strong> />
E2<<strong>br</strong> />
E3<<strong>br</strong> />
E4<<strong>br</strong> />
Fig. 6.12 - Interferência de múltiplos feixes.<<strong>br</strong> />
∞<<strong>br</strong> />
∑<<strong>br</strong> />
i=<<strong>br</strong> />
1<<strong>br</strong> />
E<<strong>br</strong> />
i<<strong>br</strong> />
= E<<strong>br</strong> />
0<<strong>br</strong> />
ττ′<<strong>br</strong> />
+<<strong>br</strong> />
E<<strong>br</strong> />
0<<strong>br</strong> />
ττ′<<strong>br</strong> />
ρ′<<strong>br</strong> />
e<<strong>br</strong> />
2 iδ<<strong>br</strong> />
+ E<<strong>br</strong> />
0<<strong>br</strong> />
ττ′<<strong>br</strong> />
ρ′<<strong>br</strong> />
e<<strong>br</strong> />
4 i2δ<<strong>br</strong> />
+ ...<<strong>br</strong> />
(6.40)<<strong>br</strong> />
S. C. Zilio <strong>Óptica</strong> <strong>Moderna</strong> – <strong>Fundamentos</strong> e Aplicações