SU731410A1 - Optical polarization device for sounding atmosphere - Google Patents

Description

one

The invention relates to the field of meteorology and the atmosphere of optics, and is intended for measuring the optical microphysical parameters of the atmosphere and can be used to control the level of pollution of the atmosphere, recognizing crystalline and gradient clouds.

Optical polarization devices for atmospheric sounding are known, consisting of a source of linearly polarized radiation from photoelectric receivers, a recording unit, and an optical system containing radiation filters that divide the other way back radiation into two mutually orthogonal components, one of which is parallel polarization plane of the emitted light stream.

In these devices, a beam of plane-polarized light is directed onto the medium and the degree of depolarization is measured, which is a criterion for the boundaries of the region of multiple light scattering. Two telescopes with photodetectors, in front of which are installed polarization filters, are used as radiation detectors.

A disadvantage of such devices is the need to use two receiving telescopes, which complicates the design of the locator and causes the difficulty of accurate

joint adjustment of telescopes on a single scattering volume. In addition, the presence of only polarization filters in the receiving path allows only the degree of depolarization to be determined without receiving information about the state of the polarization of the reflected wave.

The closest technical solution to the invention is optical polarization.

10 is a device consisting of a source of linearly-polarized light, one receiving telescope with a polarization splitter (Wollaston prism) and two photo-detectors.

In this device, Wollaston's prism is ormed so that, at its output, one of the components of the ECO ring is parallel to the plane of polarization of the emitted light flux, and the second is orthogonal to it {2. The drawback of the device is that it is difficult to isolate areas consisting of non-spherical particles in the meteorological formation and indicate their preferential

25 spatial orientation. This is due to the fact that the probe radiation and the polarization splitter have the orientation of the polarization planes strictly fixed in space, which does not allow

30 fix observed in experiment

due to the presence of non-sphericity of particles of rotation and polarization planks.

The purpose of the invention is the detection of non-spherical particles.

This goal is achieved by the fact that the proposed device for atmospheric sounding, containing a radiation source, an infrared telescope with a field-effect splitter-analyzer and two photodetectors, is equipped with a rotary quarter-wave phase illumination, installed at the entrance of the polarization splitter, an analyzer with a ventilator, with a ventilator. in the vertical or horizontal planes perpendicular to the optical axis of the optical telescope and at an angle of 45 ° to this location.

The drawing shows a block diagram of an optical polarization device for atmospheric sounding.

The device contains a source of 1 polarized radiation. Near the transmitter system is a receiving telescope 2 with an angle of vision that completely covers the entire light beam directed into the atmosphere. Immediately behind the focal plane of the receiving telescope there is a rotary phase plate 3, behind which a polarizing splitter-analyzer 4 is installed, having linear dimensions exceeding the diameter of the light beam incident on them. At the output of the polarization diluent-analyzer 4, photodetectors 5 and 6 are installed on the separated optical rays, electrically connected to the registration unit 7.

1000 0100 000-1 0010

the light beam has the following parameters

/ o QO

-P f / o

Further, the luminous flux is coupled to a polarization splitter-analyzer 4, which splits it into two mutually orthogonal components a and yy.

The orthogonal components are directed to the photodetectors 5 and 6, where the optical signals are converted to electrical and fixed in the recording unit 7.

Thus, with the orientation of the phase plate at the azimuth angle

The device works as follows.

From the radiation source 1, polarized radiation, the polarization state of which is described by the four Stokes parameters / o, Qo, t / o, Vo, is directed to the atmosphere. In this record, the parameter / corresponds to the intensity of the radiation, and the parameters Q, LJ, V describe, respectively, the predominant horizontal polarization, the polarization at an angle of 45 ° and the ilivocircular polarization.

All four parameters of the item are measured by size, and are determined by

scalar components of the electric field O.V II a, j, which are to be directly measured

 + al; Q - al -

and 2a ay-cos y; ... ay-sinT,

where Y defines the phase angle between the components a, v and yy.

If, then the direction of rotation is right, and when - the left.

Radiation scattered by the atmosphere in the opposite direction, is fed to the receiving telescope 2 and then directed to the phase plate 3. Let the azimuth axis 1 of the axis be at the initial moment of time; the first phase velocity plate is

90 °, then at the output of the phase plate, described for this by a different Muller matrix

/ o QO

f / 0 0

90 ° The following components of the Stokes vector are determined:

/.- aH “HQ a2-a2.

At the second time point, the phase plate is set at an azimuthal angle of 45 ° and the radiation of the radiated radiation is again sent to the atmosphere. In this case, at the output of the phase plate described for this and the matrix

Claims (2)

Claim An optical polarizing device for sensing the atmosphere, containing a source of polarized radiation, a receiving telescope with a polarizing splitter-analyzer and two photodetectors connected to the recording unit, 5 characterized in that, in order to detect particles of a non-spherical shape, it is equipped with a quarter-wave phase plate mounted at the input a polarization analyzer splitter with a power of 10 fixing it with the axis of greatest transmission in the vertical or horizontal perpendicular planes larly to the optical axis of the receiving telescope and at 45 ° to this' arrangement. 15 Sources of information taken into account in the examination 1. USSR Copyright Certificate Ae 373602, cl. G 01W 1/00, 1971. 2. Abstracts of the IV All-Union sim20 position on laser sensing of the atmosphere. Ed. IOA SB AS USSR, Tomsk, 1976, p. 236.