Process for preparing low-temperature phase barium metaborate monocrystalline film through magnetron sputtering

Abstract

A process for preparing a low-temperature phase barium metaborate monocrystalline film through magnetron sputtering, is characterised by selecting a beta-BBO ceramic target material or a beta-BBO single crystal material, using a magnetron sputtering method to form a layer of a beta-BBO / alpha-BBO composite single crystal film on an alpha-BBO single crystal substrate. The process of the invention overcomes a problem of difficult machining on a growed single crystal by a conventional technic, largely saves materials. The invention is suitable for mass production, can satisfy rapid-developping market request of a laser technic, has a good economic benefit.

Description

technical field [0001] The invention relates to a low-temperature phase barium metaborate (β-BaB 2 o 4 , referred to as β-BBO) single crystal thin film preparation method, specifically, in the high temperature phase barium metaborate (α-BaB 2 o 4 , referred to as α-BBO) single crystal substrate to grow a layer of low-temperature barium metaborate single crystal thin film material. β-BBO / α-BBO composite functional film is an excellent nonlinear optical material with a very wide application prospect. Background technique [0002] Barium metaborate BaB 2 o 4 There are two phases, a high temperature phase (α phase) and a low temperature phase (β phase), and the phase transition temperature is 925°C. α-BBO has a center of symmetry and is a UV birefringent crystal with excellent performance. It can be grown by ordinary pulling method and crucible drop method. See Journal of Crystal Growth, Volume 191, 1998, page 517, and patent ZL97106378. 8. "Growth method of high-temperat...

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Problems solved by technology

[0004] The growth of β-BBO single crystal in the prior technology belongs to the flux method (also known as the molten salt method), and its disadvantages are: (1) The growth rate is slow and the growth cycle is long, and the growth cycle of a single crystal is as long as 1 to 3 months; ( 2) Processing is difficult, because with the development of laser technology towards integration and miniaturization, especially in the field of femtosecond laser technology, in order to overcome the group velocity between the fundamental frequency light and the double frequency light caused by the thickness of the crystal Due to the mismatch problem, thinner β-BBO crystals are often required as frequency doubling devices (see Acta Optics Sinica, Vol. 15, 1995, p. 641), while β-BBO crystals are soft and have low mechanical strength. Especially in the process of processing into thinner parts, there are problems such as easy cracking and deformation (see Optical Technology, 1998, No. 4, page 39), such as processing the β-BBO crystal grown by the prior technology into It is very difficult to make micron-scale or even thinner wafers, and it will also cause a great waste of materials. At the same time, the growth efficiency is low, which is far from meeting the needs of the rapidly developing laser technology.

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