280
3 Holographic Interferometry for Studying …
on one or several light-sensitive layers recorded on different wavelengths, and for
image reconstruction a light beam with a variable spectral composition is used.
A number of sources of different lengths can be used (or a tunable laser, for
example, Raduga-3 M, Raduga-6) [26, 39, 61, Chap. 1]. And while obtaining a
combined image, hologram of the same object (and possibly of different objects
during creation of combined composition scenes) is recorded several times on separate emulsion layers and the wavelength of the laser source radiation is tuned each
time. For example, a three-color object is recorded on the first hologram at a wavelength λ 1 ~ 640 nm (red color), on the second one—the same object at a wavelength
λ 2 ~ 550 nm (green color) and at a wavelength λ 3 ~ 450 nm (blue color) (Figs. 3.49,
3.51 and 3.52). Sources with tunable spectral characteristics are used to control reconstruction process (e.g., with changeable light filters), as a result the recorded images
are reconstructed in turn in different wavelengths due to high spectral selectivity of
a 3D hologram. If the spectral radiation composition is changed very fast, the effect
of colorful image perception is reached, which is analogous to one during reconstruction of the three initial holograms (each was recorded at different wavelengths)
with a source with a broad spectral composition (Fig. 3.53). The similar operation of
image control can be conducted through illumination of a colorful hologram, which
was recorded on one emulsion in three wavelengths in the method mentioned above.
But qualitative recording of colorful images on one hologram is inefficient due to
limitations in spectral sensitivity and low diffraction efficiency of the registering
media.
If a plane image of an object is presented in a form of a hologram, then it will be
added with three-dimensional components. Meanwhile, the substrates are mutually
located in such a way that during reconstruction contours of the holographic and the
plane images coincide with each other. Light with variable spectral composition is
used during reconstruction (see Fig. 3.53). The suggested sequence of actions gives
the possibility to change the intensity of any spectral component of the reconstructing
radiation and as a result to correct the color distribution in the image.
Another possibility is when holograms of at least one object are formed in its
different positions on different light-sensitive polarization layers, and to reconstruct
the formed image a light beam with variable directions of polarization vector is used.
In this case, enhancement of visual efficiency of this method is reached through
registration of several holograms of the object on one substrate with a set orientation
of the object. The holograms were recorded under change of polarization vector
direction in compliance with the object orientation. And for reconstruction of the
image, both substrates (with holograms and plane images) are illuminated by a light
beam with changeable direction of polarization vector. And the substrate with the
plane image can present changeable data. The polarization filter 7 (see Fig. 3.54)
is placed in front of the image of the object, the hologram of which is recorded
on the photoplate 2, and the formed image is reconstructed with a light source with
changeable polarization vector direction. In this case, any light-sensitive material can
serve as a substrate: photographic emulsion, chromed gelatin, shellac, liquid crystals,
photoresists, etc. A light source of a certain spectral composition and with changeable
polarization vector direction is used. If the polarization vector direction is changed
3 Holographic Interferometry for Studying …
on one or several light-sensitive layers recorded on different wavelengths, and for
image reconstruction a light beam with a variable spectral composition is used.
A number of sources of different lengths can be used (or a tunable laser, for
example, Raduga-3 M, Raduga-6) [26, 39, 61, Chap. 1]. And while obtaining a
combined image, hologram of the same object (and possibly of different objects
during creation of combined composition scenes) is recorded several times on separate emulsion layers and the wavelength of the laser source radiation is tuned each
time. For example, a three-color object is recorded on the first hologram at a wavelength λ 1 ~ 640 nm (red color), on the second one—the same object at a wavelength
λ 2 ~ 550 nm (green color) and at a wavelength λ 3 ~ 450 nm (blue color) (Figs. 3.49,
3.51 and 3.52). Sources with tunable spectral characteristics are used to control reconstruction process (e.g., with changeable light filters), as a result the recorded images
are reconstructed in turn in different wavelengths due to high spectral selectivity of
a 3D hologram. If the spectral radiation composition is changed very fast, the effect
of colorful image perception is reached, which is analogous to one during reconstruction of the three initial holograms (each was recorded at different wavelengths)
with a source with a broad spectral composition (Fig. 3.53). The similar operation of
image control can be conducted through illumination of a colorful hologram, which
was recorded on one emulsion in three wavelengths in the method mentioned above.
But qualitative recording of colorful images on one hologram is inefficient due to
limitations in spectral sensitivity and low diffraction efficiency of the registering
media.
If a plane image of an object is presented in a form of a hologram, then it will be
added with three-dimensional components. Meanwhile, the substrates are mutually
located in such a way that during reconstruction contours of the holographic and the
plane images coincide with each other. Light with variable spectral composition is
used during reconstruction (see Fig. 3.53). The suggested sequence of actions gives
the possibility to change the intensity of any spectral component of the reconstructing
radiation and as a result to correct the color distribution in the image.
Another possibility is when holograms of at least one object are formed in its
different positions on different light-sensitive polarization layers, and to reconstruct
the formed image a light beam with variable directions of polarization vector is used.
In this case, enhancement of visual efficiency of this method is reached through
registration of several holograms of the object on one substrate with a set orientation
of the object. The holograms were recorded under change of polarization vector
direction in compliance with the object orientation. And for reconstruction of the
image, both substrates (with holograms and plane images) are illuminated by a light
beam with changeable direction of polarization vector. And the substrate with the
plane image can present changeable data. The polarization filter 7 (see Fig. 3.54)
is placed in front of the image of the object, the hologram of which is recorded
on the photoplate 2, and the formed image is reconstructed with a light source with
changeable polarization vector direction. In this case, any light-sensitive material can
serve as a substrate: photographic emulsion, chromed gelatin, shellac, liquid crystals,
photoresists, etc. A light source of a certain spectral composition and with changeable
polarization vector direction is used. If the polarization vector direction is changed