2
1 Resonance Methods for Increasing Sensitivity of Interferometry …
the case of absorption line, which has dispersive profile in the assumption of the
final width of the probing radiation line. Results of the studies visually confirmed
the advantage of using dye lasers in this method. So, for example, during the experiment on the detection of the sodium atoms concentration Rhoda mine 6G laser with
wavelength adapted to the resonance transition NaI (λ = 589.66 nm) was used [39].
Further in the works [40, 41], detecting the concentration of excited hydrogen atoms
in the laser-induced spark or studying the laser flare on the target containing lithium
generating dye solution replacement was made that was provided by another resonance line wavelength: hydrogen H α (λ = 656.3 nm) or Li (λ = 670.7 nm). These
joint studies made it possible to extend the number of studied plasma components
and also increase the sensitivity of resonance interferometry method [27].
As the objects for testing of resonance methods of increasing interferometry sensitivity, fluorescence and dynamic holography sodium plasma (the flame of alcoholic
lamp and arc discharge), high-temperature hydrogen plasma in the facility of tokamak
and also atomic sodium vapors have been chosen.
The results of the present work on the application of the dye laser for resonance
interferometry, fluorescence and holography opened the prospects and were used
during resonance-holographic, resonance-interference and resonance-fluorescent
plasma studies in the Plasma Optics Department of Leningrad Physics and Technology Institute named after A. F. Ioffe of the Academy of Sciences of the USSR
(study supervisors A. N. Zaidel, Yu. I. Ostrovsky, G. V. Ostrovskaia, and the author
who was one of the employees of this department at that time). Resonance fluorescence experiments carried out by the employees of the Institute of Plasma Physics
Laboratory G. T. Razdobarin, V. V. Semenov and others in association with the
employees of the Laser Plasma Diagnostics Laboratory of the Institute of Physics
of the Academy of Sciences of the BSSR (supervisor V. S. Burakov) along with
the author enabled to determine neutral hydrogen atom concentration under plasma
excitation by dye laser radiation with lamp pumping [13] with resonance line
wavelength H α .
For efficient realization of these coherent-optical methods, it was necessary to
develop and manufacture pulsed wavelength-tuned dye laser radiation with laser and
lamp pumping and to determine its optimal operation.
During these studies, there was a need to study space and temporal coherence
of dye laser radiation, the mode structure of which changes from pulse to pulse. In
connection with the absence of the methods of measurement of spatial coherence
radiation of such light sources, holographic step and holographic integral methods
were proposed and developed [42, 43]. Also for spatial coherence function (SCF)
measurement, the device of radiation laser source was proposed, developed and made.
It was named a coherometer [44].
The necessity of the step method development was caused by the fact that usual
holographic method because of its nonlinearity of the record, inherent to actual
photomaterials, does not make it possible to measure mutual-coherence γ of laser
edge points having essentially different radiation brightness. In this case, the use of
the set of holograms photographed with different exposure (step attenuation) enables
1 Resonance Methods for Increasing Sensitivity of Interferometry …
the case of absorption line, which has dispersive profile in the assumption of the
final width of the probing radiation line. Results of the studies visually confirmed
the advantage of using dye lasers in this method. So, for example, during the experiment on the detection of the sodium atoms concentration Rhoda mine 6G laser with
wavelength adapted to the resonance transition NaI (λ = 589.66 nm) was used [39].
Further in the works [40, 41], detecting the concentration of excited hydrogen atoms
in the laser-induced spark or studying the laser flare on the target containing lithium
generating dye solution replacement was made that was provided by another resonance line wavelength: hydrogen H α (λ = 656.3 nm) or Li (λ = 670.7 nm). These
joint studies made it possible to extend the number of studied plasma components
and also increase the sensitivity of resonance interferometry method [27].
As the objects for testing of resonance methods of increasing interferometry sensitivity, fluorescence and dynamic holography sodium plasma (the flame of alcoholic
lamp and arc discharge), high-temperature hydrogen plasma in the facility of tokamak
and also atomic sodium vapors have been chosen.
The results of the present work on the application of the dye laser for resonance
interferometry, fluorescence and holography opened the prospects and were used
during resonance-holographic, resonance-interference and resonance-fluorescent
plasma studies in the Plasma Optics Department of Leningrad Physics and Technology Institute named after A. F. Ioffe of the Academy of Sciences of the USSR
(study supervisors A. N. Zaidel, Yu. I. Ostrovsky, G. V. Ostrovskaia, and the author
who was one of the employees of this department at that time). Resonance fluorescence experiments carried out by the employees of the Institute of Plasma Physics
Laboratory G. T. Razdobarin, V. V. Semenov and others in association with the
employees of the Laser Plasma Diagnostics Laboratory of the Institute of Physics
of the Academy of Sciences of the BSSR (supervisor V. S. Burakov) along with
the author enabled to determine neutral hydrogen atom concentration under plasma
excitation by dye laser radiation with lamp pumping [13] with resonance line
wavelength H α .
For efficient realization of these coherent-optical methods, it was necessary to
develop and manufacture pulsed wavelength-tuned dye laser radiation with laser and
lamp pumping and to determine its optimal operation.
During these studies, there was a need to study space and temporal coherence
of dye laser radiation, the mode structure of which changes from pulse to pulse. In
connection with the absence of the methods of measurement of spatial coherence
radiation of such light sources, holographic step and holographic integral methods
were proposed and developed [42, 43]. Also for spatial coherence function (SCF)
measurement, the device of radiation laser source was proposed, developed and made.
It was named a coherometer [44].
The necessity of the step method development was caused by the fact that usual
holographic method because of its nonlinearity of the record, inherent to actual
photomaterials, does not make it possible to measure mutual-coherence γ of laser
edge points having essentially different radiation brightness. In this case, the use of
the set of holograms photographed with different exposure (step attenuation) enables