Open access

Inherent modulation: a fast chopping method for nulling
interferometry
1
±π/2
2
109106
3

n(Lk,δ
k)
R(θ, φ)E(θ, φ) (θ, φ)
4
R(θ, φ)=|E(θ, φ)|2=
n
k=1
Akei2π(Lkθ/λ)cos(δk−φ)eiφk
2
,
Akφkk
Ai=1
S t a r
P l a n e t
S k y p l a n e
T e l e s c o p e s
p l a n e
L
2
L
1
d
2
d
1
= 0
q
f
O
θ=(θ, φ)k
Lk=(Lk,δ
k)
105 5
θ4θ6θ
6
•

•
µ
•
7
5
1/fα
1
1
π
θ4
π/2−π/2
R12(θ, φ)R21(θ, φ)
R12(θ, φ +π)=R21(θ, φ)
R12(θ, φ)= 1
2|E1(θ, φ)+eiπ/2E2(θ, φ)|2,
R21(θ, φ)= 1
2|E1(θ, φ)+e−iπ/2E2(θ, φ)|2.
R12(θ, φ)= 1
2|E1(θ, φ)|2+1 2|E2(θ, φ)|2+|E1(θ, φ)||E2(θ, φ)|sin(arg E1(θ, φ)−arg E2(θ, φ)) ,
R21(θ, φ)= 1
2|E1(θ, φ)|2+1 2|E2(θ, φ)|2−|E1(θ, φ)||E2(θ, φ)|sin(arg E1(θ, φ)−arg E2(θ, φ)) .

T w o s u b - n u l l i n g
i n t e r f e r o m e t e r s ,
r e a l p u p i l
T r a n s m i s s i o n
m a p s , w i t h
q4 t r a n s m i s s i o n
T w o a s y m m e t r i c
m a p s , c o n j u g a t e d
b y c e n t r a l s y m m e t r y
M o d u l a t i o n m a p
= a l t e r n a t o r
z 0 p h a s e s h i f t
z p p h a s e s h i f t
= b e a m - c o m b i n e r
( a ) ( b ) ( c ) ( d ) ( e )
Ei(θ, φ+π)=¯ Ei(θ, φ)i=1,2
arg Ei(θ, φ +π)=−arg Ei(θ, φ)R12(θ, φ +π)=
R21(θ, φ)
ME(θ, φ)=|R12(θ, φ)−R21(θ, φ)|
n
k=1 D2
k
=2|E1(θ, φ)||E2(θ, φ)|
n
k=1 D2
k
sin(|arg E1(θ, φ)−arg E2(θ, φ)|),
Dkk
Ei(θ, φ)
1
8
•
•
•θ4θ6

•π
•
x m1m2...mnx
n mi
8
300 ×300 µ
8
7
θ4
6