240
3 Holographic Interferometry for Studying …
1.1. The principle optical scheme of the complex is presented in Fig. 3.31
where O is the object under study; 1 is the ruby laser; 2 is the beam
splitter; 3 is the lens (a negative one); 4, 5, 10 are the flat mirrors; 6 is the
electrooptical device (based on KDP crystal, Pockels or Kerr cell); 7 is the
two-beam-refractive prism of Glan; 8 is the flat piezoelectric mirror; 9, 9’
are the polarizers; 11 is the λ/2 plate; 12, 13 are the telescopic systems;
14 is the medium for hologram recording, including the reversible carrier;
15 is the optical system of interferogram formation; 16 is the registration
system; 17 is He–Ne laser; 18 is the plate for laser beam shift perpendicular
to the plane of the drawing; 19 is the λ/4 plate; 20 is the semitransparent
plate; 21 is the device for input of the set phase shift; 22 is the device for
electronic signal processing and input into a computer; 23 is the computer;
24 is the display.
1.2. The optical scheme works in the following way.
The ruby pulse laser radiation with λ 1 = 694.3 nm is reflected from the beam
splitter 2 and with the lens 3 illuminated the studied surface of the object O. The scattered by the object radiation is recorded on the medium for the hologram recording
14. A part of the radiation passed through the beam splitter 2 with the mirrors 4, 5
is directed to the electrooptical device 6, which can be in the form of KDP crystal,
Pockels or Kerr cell.
When one of the pulses of the two-pulse laser radiation passes to the device 6,
electrical radiation is applied, as a result, the polarizer plane of the passing linearpolarized radiation turns into 90°. The beam splitter 7 splits the radiation into two
beams, one of which passes through the polarizer 9
, the λ/2 plate 11, broadens with
the telescopic system 13 and illuminates the light-sensitive layer of the holographic
medium 14. The second beam is reflected from the mirror 10, which gives the possibility to oscillate with the help of the piezoelectric element 8, passes through the
polarizer 9, which is set in the crossed state in relation to the polarizer 9
, broadens
with the telescopic system 12 and also illuminates the medium for hologram recording
14. As the voltage onto the device 6 is supplied at passing of one of the pulses, the
pulses of the laser radiation will be reciprocally orthogonally polarized and thus each
of the polarizers 9 and 9
will pass only one of the pulses. As a result of this each of
the holograms formed between two pulses will be recorded with its reference waves,
which are spatially separated. Reconstruction of the holograms is conducted with
the continuous He–Ne laser 17, λ = 632.8 nm. The laser radiation passes through
the plane-parallel plate 18, which can turn in the vertical plane and serves for adjustment shifts of the laser beam in the plane, which is perpendicular to the plane of
the drawing. Then the radiation becomes circularly polarized after having passed
through the diagonal plate λ/4 and using the mirrors 4, 5 is directed onto the beam
splitter 7. The beam splitter 7 splits the radiation into reconstructing beams, which
spread in the same directions as the reference ones do. One of the beams passes
through the polarizer 9
, then through the plate λ/2, which turns its polarization
plane at 90°, and then it broadens with the telescopic system 13 and illuminates the
hologram 14. The second beam is reflected from the mirror 10, passes through the
3 Holographic Interferometry for Studying …
1.1. The principle optical scheme of the complex is presented in Fig. 3.31
where O is the object under study; 1 is the ruby laser; 2 is the beam
splitter; 3 is the lens (a negative one); 4, 5, 10 are the flat mirrors; 6 is the
electrooptical device (based on KDP crystal, Pockels or Kerr cell); 7 is the
two-beam-refractive prism of Glan; 8 is the flat piezoelectric mirror; 9, 9’
are the polarizers; 11 is the λ/2 plate; 12, 13 are the telescopic systems;
14 is the medium for hologram recording, including the reversible carrier;
15 is the optical system of interferogram formation; 16 is the registration
system; 17 is He–Ne laser; 18 is the plate for laser beam shift perpendicular
to the plane of the drawing; 19 is the λ/4 plate; 20 is the semitransparent
plate; 21 is the device for input of the set phase shift; 22 is the device for
electronic signal processing and input into a computer; 23 is the computer;
24 is the display.
1.2. The optical scheme works in the following way.
The ruby pulse laser radiation with λ 1 = 694.3 nm is reflected from the beam
splitter 2 and with the lens 3 illuminated the studied surface of the object O. The scattered by the object radiation is recorded on the medium for the hologram recording
14. A part of the radiation passed through the beam splitter 2 with the mirrors 4, 5
is directed to the electrooptical device 6, which can be in the form of KDP crystal,
Pockels or Kerr cell.
When one of the pulses of the two-pulse laser radiation passes to the device 6,
electrical radiation is applied, as a result, the polarizer plane of the passing linearpolarized radiation turns into 90°. The beam splitter 7 splits the radiation into two
beams, one of which passes through the polarizer 9
, the λ/2 plate 11, broadens with
the telescopic system 13 and illuminates the light-sensitive layer of the holographic
medium 14. The second beam is reflected from the mirror 10, which gives the possibility to oscillate with the help of the piezoelectric element 8, passes through the
polarizer 9, which is set in the crossed state in relation to the polarizer 9
, broadens
with the telescopic system 12 and also illuminates the medium for hologram recording
14. As the voltage onto the device 6 is supplied at passing of one of the pulses, the
pulses of the laser radiation will be reciprocally orthogonally polarized and thus each
of the polarizers 9 and 9
will pass only one of the pulses. As a result of this each of
the holograms formed between two pulses will be recorded with its reference waves,
which are spatially separated. Reconstruction of the holograms is conducted with
the continuous He–Ne laser 17, λ = 632.8 nm. The laser radiation passes through
the plane-parallel plate 18, which can turn in the vertical plane and serves for adjustment shifts of the laser beam in the plane, which is perpendicular to the plane of
the drawing. Then the radiation becomes circularly polarized after having passed
through the diagonal plate λ/4 and using the mirrors 4, 5 is directed onto the beam
splitter 7. The beam splitter 7 splits the radiation into reconstructing beams, which
spread in the same directions as the reference ones do. One of the beams passes
through the polarizer 9
, then through the plate λ/2, which turns its polarization
plane at 90°, and then it broadens with the telescopic system 13 and illuminates the
hologram 14. The second beam is reflected from the mirror 10, passes through the