Preparation method of barium metaborate crystal electric field sensor based on angular optical biasing

Abstract

The invention relates to a preparation method of a barium metaborate crystal electric field sensor based on an angular optical biasing, which belongs to the technical field of measurement of a high-voltage field. According to the method, a barium metaborate crystal is used as the sensing material of the electric field sensor, and in the fixed shaft cutting process of the crystal, the optical axis c of the crystal is controlled to form a smaller angle with the normal direction of a light transmission face. The angle is determined according to the wavelength of a laser source, the refractive index of the barium metaborate crystal under the wavelength and the length of the light transmission direction of the crystal. Linear sensing of the electric field is realized by means of static light wave phase biasing generated by natural birefringence of a paraxial beam of the barium metaborate crystal. The electric field sensor prepared by the method can measure the amplitude of the electric field intensity and can further measure information of the electric field such as frequency and phase, so that the sensor is a time domain measurement electric field sensor and has the advantages of higher measuring sensitivity, quick response speed, wide measuring range and frequency range, simpler structure, good stability and small interference to the electric field to be measured.

Description

technical field [0001] The invention relates to a method for preparing a barium metaborate crystal electric field sensor based on angular light bias, and belongs to the technical field of high-voltage electric field measurement. Background technique [0002] In the 1980s, with the development of optical technology, photoelectric electric field sensors gradually became a research hotspot. Photoelectric electric field sensors based on electro-optic effect can be divided into integrated optical type and bulk material type. Among them, the bulk material type electric field sensor is based on a discrete device, using a 1 / 4 wave plate to set a static operating point, and using a whole piece of electro-optic crystal to realize electric field sensing. With the advancement of micromachining technology, this type of sensor has the advantages of all-dielectric materials, which has important research significance and practical value. [0003] The performance of bulk-type electric fiel...

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Problems solved by technology

Lithium niobate crystal has a large electro-optic coefficient, high light transmittance, good optical uniformity, hard texture, no deliquescence, easy growth and processing, and has been considered as a suitable sensing material for electric field sensors for a long time, but The refractive index of lithium niobate crystals becomes uneven under strong light and ultraviolet irradiation, and is prone to damage, and the refractive index changes greatly with temperature, and there is a pyroelectric effect

Lithium tantalate crystals have similar disadvantages to lithium niobate

Bismuth germanate crystal is an artificial crystal grown from a melt, theoretically without natural birefringence, optical activity and pyroelectric effect, and has good temperature stability in the wavelength range of 800~1500nm, but bismuth germanate Under the action of an external electric field in any direction, the main axis of the crystal is uncertain. The electric field sensor using bismuth germanate crystal as the sensing material is inconvenient when measuring the space electric field. Generally, bismuth germanate crystal is used as the material of the voltage sensor.

[0004] On the other hand, the traditional bulk material type electric field sensor uses the 1 / 4 wave plate to generate a static phase offset of π / 2 to realize the linear sensing of the electric field, expand the linear measurement range, and improve the sensitivity, but the practicality of the 1 / 4 wave plate The amount of phase delay is easily affected by factors such as ambient temperature, processing accuracy, and additional stress, and its fast and slow axes will also produce mismatch deviations during the alignment process with the electro-optic crystal, reducing the accuracy of measurement

In the previous research on optical voltage sensors, it was proposed to use the natural birefringence of the near-axis beam of lithium niobate crystals to generate a static phase bias of π / 2, but the crystal x 1 Direction pressurization, x 3 In this sensing mode, the main axis of the crystal will rotate, and the paraxial beam needs to be generated by rotating the crystal, which is inconvenient in operation, increases the complexity of the sensor, and reduces the Sensor Stability

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