Borate birefringent crystal for ultraviolet and deep ultraviolet, and growth method and application thereof

Abstract

The invention relates to a borate birefringent crystal for ultraviolet and deep ultraviolet. The birefringent crystal has a chemical formula Ba2Mg (B3O6)2, belongs to trigonal system, and has a space group of R-3; and a equals to 0.70528 (3) nm, and C equals to 1.65520 (9) nm, and Z equals to 12. The barium magnesium borate birefringent crystal is an aniaxial negative crystal with ne less than no, has a transmission range of 177-3000 nm and birefringence between 0.077-0.229, and is easy for cutting, grinding, polishing and storage, stable in air, and hardly deliquesced. The barium magnesium borate birefringent crystal is subjected to a self-melt spontaneous crystallization method, a melt Czochralski method or a fluxing medium method for growth; the barium magnesium borate birefringent crystal has large birefringence (no-ne = 0.077-0.229), has important application to fields of optics and communication for the production of polarized beam splitting prism.

Description

technical field [0001] The present invention relates to the borate birefringence crystal that can be used for ultraviolet deep ultraviolet, especially a kind of molecular formula that is used for ultraviolet deep ultraviolet is Ba 2 Mg(B 3 o 6 ) 2 Barium magnesium borate (abbreviation: BMBO) birefringent crystal and its preparation and use. Background technique [0002] A beam of light incident on an anisotropic medium becomes two beams of light after being refracted, which is called birefringence. The two beams of light after refraction are both linearly polarized light and the vibration directions are perpendicular to each other. One beam follows the law of refraction and is called ordinary light (o light), and the other beam does not follow the law of refraction and is called extraordinary light (e light). Due to the anisotropy of the crystal material, the angle between the two refracted rays is related to the propagation direction and polarization state of the light ...

AI Technical Summary

Problems solved by technology

MgF 2 The transmission range of the crystal is 110-8500nm, it is a good material for deep ultraviolet, but its birefringence is too small, it is not suitable for making Glan prism, it can only be used for Rochon prism, and The separation angle of the speed of light is small, the size of the period is large, and it is inconvenient to use; the birefringence of the quartz crystal is also small, and the same problem exists; YVO 4 Crystal is an excellent artificial birefringent crystal, but its transmission range is 400-5000nm and cannot be used in the ultraviolet region; calcite crystal has a large birefringence and is the most commonly used birefringent crystal, but it mainly exists in natural forms. The impurity content is relatively high, ordinary crystals can only be used in the band above 350nm, and it is difficult to obtain ultraviolet optical grade calcite crystals, and its use band cannot reach the deep ultraviolet region (<250nm)

Several borate birefringent crystals have been reported in recent years: the high-temperature phase BaB 2 o 4 The transmission range of (α-BBO) crystal is 189-3500nm, and the birefringence is relatively large, but the crystal is easy to deliquescence, and there is a solid-state phase transition, which is easy to crack during the crystal growth process, which affects the yield and utilization rate of the crystal. , and its UV cut-off wavelength is 189nm, which limits its use in the band below 200nm; Ca 3 (BO 3 ) 2 The transmission range of the crystal is 180-3800nm, the disadvantage is that the birefringence in the visible region is small, and the transmission in the deep ultraviolet region is not high, which also limits its use; YBa 3 B 9 o 18 Due to the rare earth elements contained in the crystal, there is absorption in the ultraviolet region, and the transmission range is only 300-3000nm, which is not suitable for the deep ultraviolet region.

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