3.1 The Holographic Method of Contouring of Static …
195
Fig. 3.3 Scheme of the registration of interferograms with holographic resonance contouring.
Reprinted from [94] with permission
ϕ = 2π m
z 1 + z
λ 1
−
z 2 + z
λ 2
+ 2π m
z p n 1
λ 1
−
2z p n 2
λ 2
,
(3.10)
where z 1 , z 2 is the distance between the sources λ 1 and λ 2 to the wall of the chamber,
respectively; n 1 is the refractive index of the object under study; n 2 is the refractive
index of the resonance medium; z is the distance between the chamber wall and the
hologram; z p is the distance between the chamber wall to the point of the object.
It is worth mentioning that the first summand in (3.10) does not influence the
value of the depth interval. Under changes of phase difference in 2 π m where m =
±1, 2, 3…, on the objects there can be observed light bands with the depth interval
calculated according to the formula
z p =
λ 1
n 1
λ 2
n 2
2
λ 1
n 1
−
λ 2
n 2
.
(3.11)
It is known that the depth interval for the two-long-wave method is set by the
formula
z λ 1 λ 2 =
λ 1 λ 2
|2n(λ 1 − λ 2 )|
.
(3.12)