SU1659949A1 - Polarizing phase-shifting light separator - Google Patents

Abstract

The invention relates to optical instrumentation, in particular to elements of polarization optics, designed to transform the polarization state of radiation in optical systems. The purpose of the invention is to simplify and increase light transmission through the use of a dielectric interference polarizer as a polarization phase-splitter beam splitter. Such an application, in turn, became possible due to the unobvious phase relationships between the spatially separated reflected and transmitted light wave components in interference polarizers - beamsplitters. 3 il.

Description

The invention relates to optical instrumentation, in particular to elements of polarization optics, designed to transform the polarization state of radiation in optical systems.

The purpose of the invention is to simplify the design and increase the light transmission.

Figures 1 and 2 depict the dependences of the relative phase shift D # between the reflected S and the transmitted P components and the reflection coefficients Rs and transmittance Tr on the reduced wavelength Ao / A calculated for some specific coatings; Fig. 3 shows one of the possible schemes for constructing an interferometer using a phase-shifting beam splitter.

A dielectric interference polarizer is an optically transparent isotropic substrate with a refractive index P with a multilayer interference coating deposited on it — a system of N alternating layers with

high pv and low mon. refractive indices. At a certain angle y0 of radiation incidence with a given wavelength as a result of multiple reflections, the difference between the reflection coefficient (transmission) S and P of the polarization component increases and the system works as a polarizer.

Achievement of the goal is possible due to the unobvious phase relationships between the spatially separated reflected S and the transmitted P components of the light wave in the interference polarizers - beamsplitters.

Figure 1 shows the dependences of the phase difference between the reflected S and the transmitted P components and the reflection coefficients Rs and transmittance Tr of a 15-layer interference polarizer of the prism type with the parameters PP 1.67; pv 2,3; Mon 1.38; 45 ° from the wavelength of the incident radiation, from which it is clear that sis C

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The system in the region of high Tp Rs 99% provides a wide range of changes in the relative phase shift from 0 to 2 liters: these components. Thus, at the fundamental wavelength, Do-K, for which the optical path difference a layer is equal to a quarter of the wavelength, the phase difference is equal to / 2.

Figure 2 shows the variation in the spectrum of the values of the phase difference D # between the reflected S and the transmitted P components and the values of the reflection coefficients Rs and transmittance Tp of a 23-layer interference plate-type polarizer with parameters 1.5; pv 1.92; Mon 1.45; y0.4.4 °, from which it can be seen that in the wavelength range of AO / A 1.045 and Ac / A 1.28, corresponding to the areas of maximum separation S and P components Rs Tp 99%, the relative phase shift is l / 4 or (27G-LH / 4).

Example.

In the interferometer circuit (Fig. 3), the light from a source with a linear (45 ° angle to the plane of the drawing) polarization is spatially separated by a phase-shifting beam splitter 1 into reflected and transmitted orthogonally polarized rays with a relative phase shift, for example O, tg / 2 or n. Each of them is reflected by corner reflector 2 and 3, respectively.

whereupon, the rays are reunited in the observation arm with doubled after repeated passage through the beam splitter 1 by a relative phase shift of 0 or n,

Then, using a similar output phase-shifting beam splitter 4, oriented at an angle of ± 45 ° to the plane of incidence of the beam splitter 1, the radiation is again divided into two beams, the phases of which

shifted to l: / 2. This output beam splitter is also an analyzer that extracts components of the same polarization from two reduced rays, i.e. forms two interference patterns in reflected and transmitted light. The reflected beam is directed at an angle of 45 ° to the plane of incidence of the beam splitter 1 (i.e., to the plane of the drawing).

Thus, at the output of the interferometer, the quadrature signals are obtained using one element of polarization optics, namely, the proposed phase-shifting beam splitter, instead of five elements in the known method

receiving such signals.

Claims (1)

Claims of the Invention The use of a dielectric interference polarizer as a polarization phase-shifting beamsplitter. t, b TR f r / o & t Well b about 0.95 Sh 1.15 1.25 1.35 1tf Л0 / Л FIG. 2 M Fig.z