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a
S
E
a
E D
D θ
A=A0Za
0
exp[ikx sin θ]dx
δ=xsin θ
O x
A
A0a=eika sin θ−1 ika sin θ
φ=ka sin θI ∝ AA∗
I= sin φ
2
φ
2!2
θ
x
a
O
δ
=x sin
θ
écran
source
ka
θ θ = 0
φ= 2π⇔sin θ∗=λ
a,
a >> λ θ∗
a < λ
a >> λ
ka
θ−π/2≤θ≤π/2

0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
-10 -5 0 5 10
f(x)
φ=ka sin θ
a∼λ
a < λ
θ
a
A=A0(Za
0
eikx sin θdx +Z2a+b
a+b
eikx sin θdx)
=aA0
eika sin θ−1
ika sin θeik(a+b) sin θ+ 1
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
-1.5 -1 -0.5 0 0.5 1 1.5
f(x,10)
f(x,2)
f(x,1)
f(x,0.5)
θ
a/λ
a
a+b
I= 4 sin ka sin θ
2
ka sin θ
2!2
cos2k(a+b) sin θ
2
b
2I1f ente − I2f entes
b >> λ b >> a) cos2((k(a+b)/2) sin θ)
1/2
sin θ

θ
x
a
O
δ =x sin θ
écran
source
2a+b
a+b
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
-10 -5 0 5 10
f1(x)*f2(x,x)
2*f1(x)
φ=ka sin θ a =b
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
-10 -5 0 5 10
f1(x)*f2(x,2.*x)
2*f1(x)
φ=ka sin θ b =a/2

b∼λ
a
b λ = 2π/k
ka kb
a
b
Polariseurs
Ligne de détection
Signal saturé
Signal non saturé x(
µ m)
x(
µ m)
Intensité
Intensité

laser obstacle caméra
a
λ= 650 ±5