SU1545182A1 - Method of depolarization of light - Google Patents

Abstract

The invention relates to technical physics, in particular to the technique of spectral analysis of polarized light. The method includes the separation of the depolarized light into orthogonally polarized components of equal intensity, the violation of the mutual coherence of these components and their subsequent combination. At the same time, in the process of violating mutual coherence, orthogonally polarized components parallelly displace one relative to another by an amount D greater than the region of spatial coherence of the light. This operation can be carried out, for example, by refraction of the rays on the surfaces of the corresponding anisotropic optical element. Due to this, the temporal characteristics of the depolarized light are preserved while maintaining its divergence and direction of propagation. 1 il.

Description

The invention relates to technical physics, in particular to the technique of spectral analysis of polarized light.

The purpose of the invention is to preserve the temporal characteristics of the depolarized light while maintaining its divergence and direction of propagation.

The drawing shows a diagram of the implementation of the method.

The method includes the separation of the depolarized light into orthogonally polarized components of equal intensity, the violation of the mutual coherence of these components and their subsequent combination. In this case, in the process of violating mutual coherence, orthogonally polarized components parallelly displace each other.

relative to each other by the value of d, greater than the region of spatial coherence of light.

Consider the passage of rays of depolarized light through device 1, which implements the proposed method. In the device, beam A is divided into two beams, polarized orthogonal to each other. In the diagram, they are denoted as A and A1. Similarly, the separation of the beam C into B and C occurs. This can be achieved, for example, by refraction of the rays on the surfaces of the corresponding anisotropic optical element. Rays A and A exit from device 1 parallel to the original beam A at a distance d from each other (similarly for rays B and B;). If the distance between rays A and B is equal to d, then it is obvious that beam C,

leaving the device will be formed by the orthogonally polarized components of the rays L and B (in the scheme A1 and B). If the orthogonal polarized components are displaced relative to each other by a distance d greater than the spatial coherence region of the light, the rays emanating from the device will be formed from incoherent orthogonally polarized components. The result is natural, unpolarized light.

In the particular case, the method can be implemented using a plane-parallel plate of a birefringent material, the optical axis of which does not lie in the plane of the plate faces and is not perpendicular to this plane, and the plate thickness is sufficient for the extraordinary beam relative to the ordinary beam to exceed the region of spatial light coherence. The size of the region of prospective coherence as applied to non-laser self-luminous light sources can be estimated as L AA-p, where K is the wavelength of light, and h is the angle of divergence of the depolarizable beam.

To achieve the best depolarization, it is necessary that the orthogonally polarized components, for example, A and A, be of equal intensity. This can be achieved by orienting the depot in such a way that the selected light polarization plane (containing, for example, the direction of the grooves of the monochromator diffraction grating or the edge refracting the edge, if such is present in the setup) is an angle and / 4 sec. the plane containing the incident beam and the optical axis of the crystal (the main plane of the crystal). If it is impossible to determine the chosen direction of light polarization earlier, a combination of two similar depolarizers rotated relative to each other should be used so that their main crystal planes form an angle of / and / 4.

An example. A weak bundle of natural light from the incandescent lamp, which passed through the floor, fell on a depolarizer, which is a plane-parallel plate of square section 3 mm thick with a side of 20 mm, made of Iceland spar. The optical axis of the crystal was an angle of 45 with a normal to

input face. Main plane

with about

The crystal has an angle of 4b with the plane of polarization of the incident light. After depolarization, the light beam was divided by the Wollaston prism into two beams, polarized orthogonally to each other, and their intensities were measured using two FZU-79, the signal from which was digitized by the ADC-14 and processed by an automated microprocessor setup. Absolute measurement error did not exceed 0.5%. When the polaroid and depolarizer rotated around the optical axis of the system relative to the Wollaston prism, the polarization of light within the measurement error was not detected.

The use of the method allows the creation of depolarizing devices capable of operating with pulse signals of a duration of the order of time, I.

nor the coherence of light (t, -).

1 AV

Claims (1)

Invention Formula A method of depolarizing light, including separating the depolarized light into orthogonally polarized components of equal intensity, disrupting the mutual coherence of these components and their subsequent combination, characterized in that, in order to preserve the temporal characteristics of the depolarized light while maintaining its divergence and direction of propagation, the process of violating mutual coherence, orthogonally polarized components parallelly displace one relative to another by an amount greater than the space of natural coherence of light. AT