A sodium lithium borate birefringent crystal, and a preparing method and uses thereof

Abstract

The invention relates to a sodium lithium borate birefringent crystal, and a preparing method and uses thereof. The chemical formula of the crystal is Li<2>Na<2>B2O5, the molecular weight of the crystal is 161.4, the crystal belongs to an orthorhombic system, and the space group is Cmcm. According to cell parameters, a is 3.313 angstroms, b is 9.985 angstroms, c is 13.400 angstroms, V is 443.3 angstrom<3>, and Z is 4. The transparent range of the crystal is 170-3500 nm. The birefringence of the crystal is between 0.108 (1064 nm) and 0.248 (200 nm). The sodium lithium borate is synthesized by adopting a solid phase reaction process. The Li<2>Na<2>B2O5 birefringent crystal grows by adopting a high-temperature melt process or a cosolvent process. The crystal prepared by the method has characteristics of proper mechanical hardness, easy cutting, polishing and storage, congruent melting, easy growth and a high birefringence, has important applications in the optical and communication fields, and can be used for manufacturing polarizing beam splitter prisms, phase delay devices, electrooptical modulators, and the like.

Description

technical field [0001] The invention relates to a birefringent crystal of compound lithium sodium borate and its preparation method and application, in particular to a compound whose molecular formula is Li for the infrared-deep ultraviolet band. 2 Na 2 B 2 o 5 Preparation method and application of lithium sodium borate birefringent crystal Background technique [0002] Birefringence refers to the phenomenon that a beam of light is projected onto the surface of a crystal to produce two beams of refracted light. The root cause of this phenomenon is the anisotropy of the crystal material. When light propagates in an optical heterogeneous homogeneous body (such as a crystal other than a cubic system), its vibration characteristics will be changed except for a few special directions (along the direction of the optical axis), and it will be decomposed into two electric field vector vibration directions Two beams of polarized light that are perpendicular to each other, have di...

AI Technical Summary

Problems solved by technology

Take MgF 2 For example, its transmission range is 110-8500nm, it is a good crystal material for deep ultraviolet, but its birefringence is too small, it is not suitable for making Glan prism, it can only be used for Luo Hungarian prism, and the separation angle of light speed is small, the size of the period is large, and it is inconvenient to use; the birefringence of quartz crystal is also small, and the same problem exists; YVO 4 The crystal is also an artificially prepared birefringent crystal, and due to the YVO 4 The melting point is high, and the iridium crucible must be used for pulling growth, and the growth atmosphere is a weak oxygen atmosphere, so there is a problem of price change of yttrium element during growth, which reduces the quality of the crystal, making it difficult to obtain high-quality crystals and its penetration. The range is 400-5000nm, it cannot be directly used in the ultraviolet region

Calcite in natural form is a birefringent crystal that is widely used, but its impurity content is relatively high. Ordinary crystals can only be used in the band above 350nm. It is difficult to obtain ultraviolet optical grade calcite crystals, and its use band cannot reach the deep ultraviolet region ( <250nm)

Rutile also mainly exists in natural form, and it is difficult to synthesize artificially, and it is small in size, high in hardness, and difficult to process

Several borate birefringent crystals have been reported in recent years: the high-temperature phase BaB 2 o 4 The transmission range of the crystal is 189-3500nm, and the birefringence is relatively large, but the crystal is prone to deliquescence, and there is phase transfer, which is easy to crack during the crystal growth process, which affects the yield and utilization of the crystal.

Images