3.1 The Holographic Method of Contouring of Static …
193
It also follows from (3.4) that the use of several beams leads to interference beam
narrowing: half-width of the interference maximum is in inverse proportion to the
quantity of interfering beams. In a case with four beams, which occurs in our studies,
the bandwidth is twice as little as the double-beam one.
The results of the experiment are in good agreement with calculation due to (3.8).
The full relief depth of the surfaces under study was measured with micrometer from
the base to the envelope of the object and is 1 mm for the sphere, 1.5 mm—for the
cylinder and 0.9 mm—for the wedge.
It is worth mentioning that in the conducted earlier works on holographic relief
detection with radiation containing several equidistant spectral lines [71], the scheme
with an inclined reference beam was used that led to hologram dispersion, i.e., to
in-plane shear of the reconstructed surfaces of the object (see, for example [92]).
In our work, for this purpose, the scheme with colliding beams was used for the
first time, which is known to form holograms without transverse dispersion [92].
To reduce exposure time, the objects were covered with paint, which has a high
diffusion reflection coefficient that made it possible to eliminate points preventing
image reconstruction. The photographs of the surface relief contours reconstructed
by the hologram are presented in Fig. 3.2, where it is seen that 10 contour lines were
reconstructed for the sphere, 15—for the cylinder, 9—for the wedge. Moreover, the
relief contours spread over the whole surface of the objects under study.
3.1.2 To the Question of the Possibility of Increasing
the Spacial Resolution of the Holographic Surface
Relief Contouring Method While Using the Resonance
Media
On the basis of a two-long-wave method, there were developed a rather great
number of holographic contouring modifications. Several works were dedicated to
the development of sensitivity enhancing principles [30, 71].
A new method is offered, with the help of which spatial resolution can be regulated.
Resonance medium is applied for its realization. Such media have already been used
during the study of plasma [95].
The scheme of holographic interferogram recording is presented in Fig. 3.3. The
object was placed into a transparent chamber with a plane window containing the
resonance medium. The medium can be gas or liquid with absorption line x (e.g.,
hemoglobin or cyanine solutions, alkali vapor of such metals as sodium, cesium,
potassium, etc.). The object is lighted by plane waves 1 and 2 from the side of
observation. Implementation of plane waves allows obtaining intersections of the
object surface by the family of planes that significantly simplifies the interpretation
of the contour map. The reflected light interferes on the hologram with two reference
193
It also follows from (3.4) that the use of several beams leads to interference beam
narrowing: half-width of the interference maximum is in inverse proportion to the
quantity of interfering beams. In a case with four beams, which occurs in our studies,
the bandwidth is twice as little as the double-beam one.
The results of the experiment are in good agreement with calculation due to (3.8).
The full relief depth of the surfaces under study was measured with micrometer from
the base to the envelope of the object and is 1 mm for the sphere, 1.5 mm—for the
cylinder and 0.9 mm—for the wedge.
It is worth mentioning that in the conducted earlier works on holographic relief
detection with radiation containing several equidistant spectral lines [71], the scheme
with an inclined reference beam was used that led to hologram dispersion, i.e., to
in-plane shear of the reconstructed surfaces of the object (see, for example [92]).
In our work, for this purpose, the scheme with colliding beams was used for the
first time, which is known to form holograms without transverse dispersion [92].
To reduce exposure time, the objects were covered with paint, which has a high
diffusion reflection coefficient that made it possible to eliminate points preventing
image reconstruction. The photographs of the surface relief contours reconstructed
by the hologram are presented in Fig. 3.2, where it is seen that 10 contour lines were
reconstructed for the sphere, 15—for the cylinder, 9—for the wedge. Moreover, the
relief contours spread over the whole surface of the objects under study.
3.1.2 To the Question of the Possibility of Increasing
the Spacial Resolution of the Holographic Surface
Relief Contouring Method While Using the Resonance
Media
On the basis of a two-long-wave method, there were developed a rather great
number of holographic contouring modifications. Several works were dedicated to
the development of sensitivity enhancing principles [30, 71].
A new method is offered, with the help of which spatial resolution can be regulated.
Resonance medium is applied for its realization. Such media have already been used
during the study of plasma [95].
The scheme of holographic interferogram recording is presented in Fig. 3.3. The
object was placed into a transparent chamber with a plane window containing the
resonance medium. The medium can be gas or liquid with absorption line x (e.g.,
hemoglobin or cyanine solutions, alkali vapor of such metals as sodium, cesium,
potassium, etc.). The object is lighted by plane waves 1 and 2 from the side of
observation. Implementation of plane waves allows obtaining intersections of the
object surface by the family of planes that significantly simplifies the interpretation
of the contour map. The reflected light interferes on the hologram with two reference