66
2 Holographic Microscopy of Phase and Diffuse Objects …
image is observed through the eyepiece, which can be moved by the field of the
recorded image. In order to produce a deep holographic image of high fidelity, it
is necessary to expose a hologram by a beam conjugated with the reference beam
(Fig. 2.2c, d). Then in the place where the object is at recording, its real image without
aberrated distortions is formed. It was formed due to its compensation during wave
distribution through the optical system in opposite direction. But this method of
aberration compensation is quite sensitive to such factors as accuracy of setting a
hologram and optical system, which makes an enlarged image of a microobject,
reference and reconstructed beams mutual inclination, wavelength changing [140].
If necessary requirements are fulfilled, then this microscope scheme provides certain
advantages. For example, as it is shown in [140], the realization of this scheme
makes it possible to study three-dimensional scene with the depth of ~10 cm and the
resolution of 2–3 μm (numerical aperture of microscope objective is 0.24).
The use of the methods of holographic interferometry in microscopy gives more
interesting possibilities during the study of phase microscopic objectives. To detect
the wavelength phase modulation passed through the transparent object, it should be
converted into amplitude modulation [141]. Usually, it is fulfilled with the help of
interference microscope (Fig. 2.3a).
In such a scheme, the optical paths of the reference beam and the beam of comparison should be carefully equalized, i.e., refractive index and glass element thickness
should be equal. The magnification should be also the same.
At the same time, any above-described holographic microscope can be transformed into an interference one. There is no need to select doubled optical details
in the holographic interference microscope precisely. Instead of it, the waves passed
the same way during different periods of time are used (Fig. 2.3b).
Fig. 2.3 Classical interference microscope (a): 1—the beam splitter, 2—the slide, 3—the microscope objectives, 4—the phase plates, 5—the light prism, 6—the ocular. Holographic interference
transmission microscope (b): 1—the laser, 2—the dividing cube, 3—the rotary mirror, 4—the object
under study, 5—the microobjective, 6—the hologram, 7—the ocular, 8—the camera; Holographic
interference reflection microscope (c): 1—the laser, 2,8—the dividing cube, 3—the rotary mirror,
4—the object under study, 5—the microobjective, 9—the rotary prism, 6—the hologram, 7—the
ocular. Reprinted from [136] with permission
2 Holographic Microscopy of Phase and Diffuse Objects …
image is observed through the eyepiece, which can be moved by the field of the
recorded image. In order to produce a deep holographic image of high fidelity, it
is necessary to expose a hologram by a beam conjugated with the reference beam
(Fig. 2.2c, d). Then in the place where the object is at recording, its real image without
aberrated distortions is formed. It was formed due to its compensation during wave
distribution through the optical system in opposite direction. But this method of
aberration compensation is quite sensitive to such factors as accuracy of setting a
hologram and optical system, which makes an enlarged image of a microobject,
reference and reconstructed beams mutual inclination, wavelength changing [140].
If necessary requirements are fulfilled, then this microscope scheme provides certain
advantages. For example, as it is shown in [140], the realization of this scheme
makes it possible to study three-dimensional scene with the depth of ~10 cm and the
resolution of 2–3 μm (numerical aperture of microscope objective is 0.24).
The use of the methods of holographic interferometry in microscopy gives more
interesting possibilities during the study of phase microscopic objectives. To detect
the wavelength phase modulation passed through the transparent object, it should be
converted into amplitude modulation [141]. Usually, it is fulfilled with the help of
interference microscope (Fig. 2.3a).
In such a scheme, the optical paths of the reference beam and the beam of comparison should be carefully equalized, i.e., refractive index and glass element thickness
should be equal. The magnification should be also the same.
At the same time, any above-described holographic microscope can be transformed into an interference one. There is no need to select doubled optical details
in the holographic interference microscope precisely. Instead of it, the waves passed
the same way during different periods of time are used (Fig. 2.3b).
Fig. 2.3 Classical interference microscope (a): 1—the beam splitter, 2—the slide, 3—the microscope objectives, 4—the phase plates, 5—the light prism, 6—the ocular. Holographic interference
transmission microscope (b): 1—the laser, 2—the dividing cube, 3—the rotary mirror, 4—the object
under study, 5—the microobjective, 6—the hologram, 7—the ocular, 8—the camera; Holographic
interference reflection microscope (c): 1—the laser, 2,8—the dividing cube, 3—the rotary mirror,
4—the object under study, 5—the microobjective, 9—the rotary prism, 6—the hologram, 7—the
ocular. Reprinted from [136] with permission