36
1 Resonance Methods for Increasing Sensitivity of Interferometry …
1.5 New Class of Detecting Media
for Holography—Gaseous Media. The Study
of the Conditions of Dynamic Gain-Phase Holograms
Recording (Plane and Bulk) in Sodium Vapors
As it is known, medium is used as a recording material for the registering dynamic
holograms. The optical properties of this medium can be changed quite fast and
reversible under electromagnetic radiation. As a rule, liquids [85, 86], crystals [87–
90] and semiconductors [91, 92] are used as such a medium. The idea to record a
dynamic hologram in gaseous medium for the first time was proposed and experimentally carried out in the work [30]. The study of the possibilities of the dynamic
hologram recording with low relaxation time in the gaseous resonance medium
is of significant interest in terms of using a new sensitive medium for hologram
recording. The studies using laser radiation-tuned frequency made it possible to
determine the conditions of dynamic gain-phase hologram recording in a new class
of detecting media—gaseous media (using sodium vapors). The results of our studies
are foreground in the science of our and foreign countries [30–35].
It is clear that gain-phase relief, which is recorded in vapors in the case of laser
radiation frequency tuning to the used atomic transition, is high enough that corresponds to the medium sensitivity increase to the dynamic hologram recording. The
sensitivity of such media is defined by the value of frequency mismatch, which forms
radiation hologram with the resonance transition of frequency of a gaseous medium.
It is conditioned by the fact that when approaching the resonance, the changes in
the refractive and absorption index increase enormously. Dye solution laser with
laser pumping should be considered as a more convenient light source for holograms recording in such media. By varying oscillator frequency of such lasers, it is
possible to tune in resonance with the used atomic transitions. In the works of A.
M. Bonch-Bruevich with the employees [93, 94], induced scattering of light beams
angularly propagated to each other in rubidium and potassium vapors was under
study. When radiation density is 10
7 –10
8 W/cm
2 , then additional light beams can be
seen in the spectrum short-wave region concerning the absorption line. Theoretical
interpretation of the detected phenomena as the process of four-photon parametric
scattering of monochromatic radiation, provided by nonlinear polarization on the
same frequency, allows the authors [93, 94] to explain the observed effects including
the absence of additional beams in long-wave spectrum parts. Moreover, in the work
[93] change of angular distribution of beams passing through the vapors could be
observed. This effect connected with changes of vapors refractive index under resonance photons absorption was observed in short-wave and long-wave spectrum parts
and also between the doublet lines (except the center of gravity of doublet-point
where vapors refractive index is 1).
In the described experiment [32], sodium vapors were used as detecting media
for holograms recording. Sodium vapors were developed in the cell (4) (Fig. 1.24c,
d) with optical transparent windows, from which beforehand with the help of a
1 Resonance Methods for Increasing Sensitivity of Interferometry …
1.5 New Class of Detecting Media
for Holography—Gaseous Media. The Study
of the Conditions of Dynamic Gain-Phase Holograms
Recording (Plane and Bulk) in Sodium Vapors
As it is known, medium is used as a recording material for the registering dynamic
holograms. The optical properties of this medium can be changed quite fast and
reversible under electromagnetic radiation. As a rule, liquids [85, 86], crystals [87–
90] and semiconductors [91, 92] are used as such a medium. The idea to record a
dynamic hologram in gaseous medium for the first time was proposed and experimentally carried out in the work [30]. The study of the possibilities of the dynamic
hologram recording with low relaxation time in the gaseous resonance medium
is of significant interest in terms of using a new sensitive medium for hologram
recording. The studies using laser radiation-tuned frequency made it possible to
determine the conditions of dynamic gain-phase hologram recording in a new class
of detecting media—gaseous media (using sodium vapors). The results of our studies
are foreground in the science of our and foreign countries [30–35].
It is clear that gain-phase relief, which is recorded in vapors in the case of laser
radiation frequency tuning to the used atomic transition, is high enough that corresponds to the medium sensitivity increase to the dynamic hologram recording. The
sensitivity of such media is defined by the value of frequency mismatch, which forms
radiation hologram with the resonance transition of frequency of a gaseous medium.
It is conditioned by the fact that when approaching the resonance, the changes in
the refractive and absorption index increase enormously. Dye solution laser with
laser pumping should be considered as a more convenient light source for holograms recording in such media. By varying oscillator frequency of such lasers, it is
possible to tune in resonance with the used atomic transitions. In the works of A.
M. Bonch-Bruevich with the employees [93, 94], induced scattering of light beams
angularly propagated to each other in rubidium and potassium vapors was under
study. When radiation density is 10
7 –10
8 W/cm
2 , then additional light beams can be
seen in the spectrum short-wave region concerning the absorption line. Theoretical
interpretation of the detected phenomena as the process of four-photon parametric
scattering of monochromatic radiation, provided by nonlinear polarization on the
same frequency, allows the authors [93, 94] to explain the observed effects including
the absence of additional beams in long-wave spectrum parts. Moreover, in the work
[93] change of angular distribution of beams passing through the vapors could be
observed. This effect connected with changes of vapors refractive index under resonance photons absorption was observed in short-wave and long-wave spectrum parts
and also between the doublet lines (except the center of gravity of doublet-point
where vapors refractive index is 1).
In the described experiment [32], sodium vapors were used as detecting media
for holograms recording. Sodium vapors were developed in the cell (4) (Fig. 1.24c,
d) with optical transparent windows, from which beforehand with the help of a