SU1196684A1 - Quantum interferometric displacement meter - Google Patents

Abstract

QUANTUM INTERFEROMETRIC DISPLACEMENT METER, contents - a laser with two optical outputs, a mirror designed to be fixed on a controlled object and optically coupled to one of the laser outputs, a photodetector optically coupled to another output No.

Description

The invention relates to a measurement technique and can be used for accurate measurements of dimensions, movements and speeds of movement of various objects, for using deformations, vibrations, surface topography, and optical properties of a medium. The purpose of the invention is to improve the accuracy of measurements by eliminating ambiguity when reversing the movement of a controlled object. The drawing shows the proposed meter. The quantum interferometric displacement meter contains two parallel-installed lasers 1 and 2 with the same optical radiation wavelength L, designed to fix a mirror 3 on the object being monitored, optically connected to lasers 1 and 2 and installed perpendicular to them by the reflecting surface to lasers 1 and 2 , two photodetectors D and 5 are optically coupled to the second outputs of lasers 1 and 2, respectively, and a signal processing unit 6, the inputs of which are connected to the outputs of photodetectors 4 and 5. Distance along the optical axis the interferometric meter from the mirror to the lasers 1 and 2 differ by the value of L, not a multiple of L / 2. The difference in the distance between the mirror 3 and the lasers 1 and 2 is necessary to obtain a phase shift that differs from O and 180 between the signals at the outputs photodetectors 4 and 5. The phase shift can also be obtained due to the difference in the optical characteristics of the media filling the space between laser 1 and mirror 3, and laser 2 and mirror 3. The device works the next time. A mirror 3 mounted on a monitored object forms a passive resonator optically coupled to a laser 1, which affects the optical radiation power of laser 1. The optical radiation modes realized in a complex three-mirror resonator formed by laser 1 and mirror 3 are not are the modes of neither laser 1 nor passive resonator. These modes can be considered as displaced modes 84 H1; W; resonator and laser 1. A change in the coupling between the passive resonator and the laser 1 causes a mode shift on the frequency scale. When a controlled object with a mirror 3 is moved along the optical axis of the laser 1, the length of the passive resonator changes. In this case, all modes implemented in a complex resonator change their Q-factor and frequency with respect to the Q-factor and frequency corresponding to the initial length of the passive resonator. Since the active medium is present only in laser 1, a decrease in the quality factor of a particular mode causes lasing of the laser 1. At the same time, the quality factor of the passive resonator mode increases, which leads to generation in this mode. After the newly zagenerated mode assumes the position of the unperturbed mode of laser 1, the radiation intensity of laser 1 reaches its maximum value. As a result, the radiation intensity of the laser 1, which is detected by the photodetector 4, cyclically changes. The full cycle of changing the intensity of laser 1 occurs when the length of the passive resonator changes by moving the object under test with mirror 3 fixed on it by an amount equal to 12. The modulation depth of the laser 1 depends on the reflection coefficient of mirror 3 and the ratio of the passive resonator and laser 1 With the reflection coefficient of the mirror 3 exceeding 25 liters and with the comparable lengths of the laser 1 and the passive resonator, the modulation depth of the laser 1 is close to 100%. Similarly, when a controlled object is moved, a cyclic change in the intensity of the laser 2 radiation occurs, which is detected by the photodetector 5. The signals at the outputs of the photoreceivers 4 and 5 are shifted one with another by an angle different from O and 180 ° due to the difference in the optical lengths of the passive resonators, due to the difference distances from mirror 3 to lasers 1 and 2 by the value of L. It is preferable to have a phase shift of 90. The signals from the outputs of photodetectors 4 and 5 are fed to

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the inputs of the signal processing unit 6, each of which corresponds to the signal processing unit 6, defined by the direction of the displacement of the grain

varying in sinusoidal and cocall 3. Divided by the impulse by the sinusoidal laws, they are transformed into a summing and subtracting

into square impulses. Poj reversible counter inputs. At the high phase ratio of the signals determined by the approach of the signal processing unit 6, the direction of movement of the moving-there is a signal corresponding to

mirror 3 and the diffusion of pulses along two channels, an important mirror 3, is performed at a D-CURRENT value of movement.

Claims (1)

QUANTUM INTERFEROMETRIC MOVEMENT MEASURER, content -. a living laser with two optical outputs, a mirror designed to be mounted on a controlled object and optically coupled to one of the laser outputs, a photodetector optically coupled to the other laser output, and a signal processing unit, characterized in that, in order to increase the measurement accuracy , it is equipped with an additional laser installed in parallel with the optical axis of the meter with a two-laser. optical outputs, one of which is optically connected to the mirror, and an additional photodetector, the input of which is optically connected to the other output of the additional laser, and the output is connected to the signal processing unit, both lasers are located relative to the mirror at distances along the optical axis of the meter, differing by a value not a multiple of L / 2, where L is the wavelength of the laser radiation. 1 . 1