1.7 Results and Conclusions
49
Among the most considerable results, the following can be singled out:
1. During the studies of dynamic resonance holography, a new class of detecting
media–gaseous media was detected. In particular, additional beams were
produced. They appeared in the result of initial beams diffraction on the gainphase grating formed in the result of radiation absorption near the contour centers
of resonance sodium lines. Additional beams could be observed in short-wave as
well as in long-wave spectrum regions. The observed effect of redistribution of
energy from strong wave to weak wave in the result of scattering on the amplitude
volume dynamic grating recorded in sodium vapors is of practical interest in the
mechanism of the control of image contrast. It qualitatively corresponds to the
conclusions of theoretical treatment proposed by V. G. Sidorovich.
The studies made it possible to determine the conditions of the recording of gainphase holograms in sodium vapors: optimal values of sodium vapors concentration,
convergence angles of the beams forming the grating, radiation density necessary
for the hologram recording, and also to find out the influence of the change of the
ratio of beam intensities, forming the grating, on a self-diffraction process.
Also, we studied the effect of rotation of the polarization plane of a weak wave
in the field of a strong wave of the same frequency detected while investigating the
influence of polarization planes mismatching of initial beams on the self-diffraction
process. In sodium vapors, these beams form volume dynamic grating.
2. The experimental study on the possibility of increasing the sensitivity of resonance interferometry method using wavelength-tuned dye laser radiation was
carried out.
Light sources with the fixed wavelength, used heretofore in the studies using the
method of resonance interferometry, considerably constrained its sensitivity. Practically always, the necessity exists to select not the light source to the particular
plasma absorption lines, but quite the contrary—the object of study—plasma to
definite, fixed laser absorption lines. Because of this fact, it was impossible to use
possibilities of increasing sensitivity of the method for the majority of the objects
under consideration.
The basic requirements were determined to light source used in the studies by the
method of resonance interferometry and the boundaries of this method applicability
for the case of the absorption line with the dispersion contour under the assumption
of finite width of the probe radiation line.
There was measured distribution of sodium atoms concentration in arc plasma and
in the alcohol lamp flame containing sodium salt. It was established that measurement
sensitivity of sodium atoms concentration considerably depends on the value of
wavelength mismatching of probe radiation from the absorption line center of sodium
resonance doublet and has its maximum when λ ~ 0.1 nm. In the case when
mismatching of probe radiation from the absorption line center is less than 0.1 nm,
strong radiation absorption by resonance line wings could be observed.
49
Among the most considerable results, the following can be singled out:
1. During the studies of dynamic resonance holography, a new class of detecting
media–gaseous media was detected. In particular, additional beams were
produced. They appeared in the result of initial beams diffraction on the gainphase grating formed in the result of radiation absorption near the contour centers
of resonance sodium lines. Additional beams could be observed in short-wave as
well as in long-wave spectrum regions. The observed effect of redistribution of
energy from strong wave to weak wave in the result of scattering on the amplitude
volume dynamic grating recorded in sodium vapors is of practical interest in the
mechanism of the control of image contrast. It qualitatively corresponds to the
conclusions of theoretical treatment proposed by V. G. Sidorovich.
The studies made it possible to determine the conditions of the recording of gainphase holograms in sodium vapors: optimal values of sodium vapors concentration,
convergence angles of the beams forming the grating, radiation density necessary
for the hologram recording, and also to find out the influence of the change of the
ratio of beam intensities, forming the grating, on a self-diffraction process.
Also, we studied the effect of rotation of the polarization plane of a weak wave
in the field of a strong wave of the same frequency detected while investigating the
influence of polarization planes mismatching of initial beams on the self-diffraction
process. In sodium vapors, these beams form volume dynamic grating.
2. The experimental study on the possibility of increasing the sensitivity of resonance interferometry method using wavelength-tuned dye laser radiation was
carried out.
Light sources with the fixed wavelength, used heretofore in the studies using the
method of resonance interferometry, considerably constrained its sensitivity. Practically always, the necessity exists to select not the light source to the particular
plasma absorption lines, but quite the contrary—the object of study—plasma to
definite, fixed laser absorption lines. Because of this fact, it was impossible to use
possibilities of increasing sensitivity of the method for the majority of the objects
under consideration.
The basic requirements were determined to light source used in the studies by the
method of resonance interferometry and the boundaries of this method applicability
for the case of the absorption line with the dispersion contour under the assumption
of finite width of the probe radiation line.
There was measured distribution of sodium atoms concentration in arc plasma and
in the alcohol lamp flame containing sodium salt. It was established that measurement
sensitivity of sodium atoms concentration considerably depends on the value of
wavelength mismatching of probe radiation from the absorption line center of sodium
resonance doublet and has its maximum when λ ~ 0.1 nm. In the case when
mismatching of probe radiation from the absorption line center is less than 0.1 nm,
strong radiation absorption by resonance line wings could be observed.