RU2545336C1 - Device for control over optical radiation parameters - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: device comprises laser radiation source, polariser, spinning optical element and feedback circuit. The latter consists of light splitting plate, extra polariser, photo detector, amplifier, optical element and rotary unit spinning rpm control unit with polarisation plane turn transducer arranged thereat.

EFFECT: control over polarisation turn angle.

2 cl, 2 dwg

Description

Technical field

The invention relates to the field of optics, and in particular to devices for controlling the parameters of laser radiation used in the practice of creating optical systems.

State of the art

A device is known that implements a method for controlling the parameters of optical radiation, including placing an optical element on the flow path and changing its optical properties by exposing the optical element to a physical factor. For example, a material containing adsorbed water is used as an optical element. Previously, the optical element is cooled to the temperature of the beginning of the restoration of hydrogen bonds in adsorbed water, and the change in the optical properties of the optical element is performed by cooling and / or heating the optical element in the region of the temperature of restoration - the destruction of hydrogen bonds in adsorbed water. (RF patent No. 2035756, publ. 05.20.1995).

Its disadvantage is that it controls exclusively the intensity of the radiation flux. There is a need for heating and / or cooling the optical element from the outside. As a result, for the correct operation of the device requires additional heating and cooling equipment.

The closest technical solution is a measuring device that contains a polarizer, after passing through which the beam enters a rotating optical element made in the form of a glass cylinder, as well as a sensor that measures the angle of rotation of the plane of polarization. (R.V. Jones, F.R.S. Rotary 'aether drag'. Department of Natural Philosophy, University of Aberdeen, Scotland. Proc. R. Soc. Lond. A. 349, 29 June 1976, p. 426). Here we use the experimentally discovered effect of changing the parameters of linearly polarized monochromatic radiation as it passes through a rotating optical medium.

The disadvantage of this device is that it does not allow you to control the parameters of optical radiation, such as, for example, rotation of the plane of polarization of the radiation, and has the ability to only measure its value.

Disclosure of invention

The objective of the invention is to provide a device that allows you to control the parameters of optical radiation, and in particular the angle of rotation of the plane of polarization and the degree of polarization.

The problem is solved in that a feedback chain consisting of a beam splitter plate, a rotary unit, on which a rotation angle sensor of the plane of polarization and an additional polarizer are installed, is introduced into the device for controlling optical radiation, which includes a laser radiation source, a polarizer and a rotating optical element. also from a photodetector, amplifier, personal computer and a central control unit for the rotation speed of the optical element.

A rotating optical element for more reliable and accurate operation can be mounted on a vibration-isolating base.

List of figures

Figure 1 shows a block diagram of a device for controlling the parameters of optical radiation.

Figure 2 presents the experimentally obtained dependence of the angle of rotation of the plane of polarization on the frequency of rotation of the optical disk with the initial horizontal polarization of the radiation at the laser output.

The implementation of the invention

The block diagram of the optical radiation parameter control device includes a laser 1, a polarizer 2, an electric motor 3, an optical disk 4, a beam splitter 5, a rotary block 6, an angle sensor 7, an additional polarizer 8, a photodetector 9, an amplifier 10, a personal computer 11 and a central control unit 12, a vibration isolating base 13.

The proposed device operates as follows.

The polarization of the initial radiation at the output of the laser 1 is selected using a polarizer 2. The beam splitter plate 5 allows you to divide the radiation transmitted through the optical disk 4 into two components, one of which goes to the output of the device, and the second to the feedback circuit. By changing the rotation frequency of the electric motor 3, it is possible to achieve the desired change in the degree of polarization or the angle of rotation of the plane of polarization based on pre-measured dependences (figure 2). The desired values are detected by turning the rotary unit 6 by an angle corresponding to the minimum or maximum value of the signal transmitted through the additional polarizer 8 to the photodetector 9, in the case of measuring the rotation angle, and both extreme signal values (minimum and maximum), in the case of determining the degree of polarization. The rotation angle of the rotary unit 6 is fixed using the angle sensor 7 mounted on it. Using the computing means of the personal computer 11, the degree of polarization is calculated. To reduce the effect of the vibrations of the electric motor 3 on the accuracy of the device, it is placed on a vibration-isolating base 13. The limits of the parameters at the output of the device can be controlled by changing the angle of incidence of the radiation on the optical disk 4, selecting an optical disk 4 from various materials and changing the initial radiation polarization at the generator output.

The inventive device allows radiation control using simple in composition, structure of methods for producing optical elements. The invention is implemented as an experimental bench based on a helium-neon laser operating at a wavelength of 0.6328 microns. As an optical element, a TF3 optical glass disk with a diameter of 62 mm and a thickness of 10 mm is used. The role of the additional polarizer is performed by the SUNPACK (PL) Polarizer 48 mm film polarizer. A high-speed PIN photodiode S5821-01 (Hamamatsu) was selected as a measuring photodetector. The frequency and direction of rotation of the motor are controlled by a Delta Electronics VFD-EL digital frequency converter.

In the calculations, a predetermined experimentally determined dependence of the angle of rotation of the plane of polarization on the frequency of rotation of the optical disk (eg, as shown in FIG. 2) is introduced into a personal computer.

Claims (2)

1. A device for controlling the parameters of optical radiation, which includes a laser source, a polarizer, a rotating optical element and a sensor measuring the angle of rotation of the plane of polarization, characterized in that a feedback chain consisting of a beam splitter plate, a rotary unit, is introduced into the circuit which contains the specified angle of rotation of the plane of polarization and an additional polarizer, also from a photodetector, amplifier, personal computer and central speed control unit Stu rotating optical element. 2. A device for controlling the parameters of optical radiation according to claim 1, characterized in that the rotating optical element is mounted on a vibration-isolating base.

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