CN100469949C

CN100469949C - A method for growing large-caliber potassium dihydrogen phosphate monocrystal

Info

Publication number: CN100469949C
Application number: CNB2004100443237A
Authority: CN
Inventors: 李国辉; 苏根博; 庄欣欣; 李征东; 贺友平
Original assignee: Fujian Institute of Research on the Structure of Matter of CAS
Current assignee: Fujian Institute of Research on the Structure of Matter of CAS
Priority date: 2004-05-25
Filing date: 2004-05-25
Publication date: 2009-03-18
Anticipated expiration: 2024-05-25
Also published as: CN1704508A

Abstract

The invention provides a method for growing large-caliber potassium dihydrogen phosphate monocrystal which comprises, charging a small amount of sulfosalicylic acid as chelating agent into saturated solution, carrying out complex reaction to make the fast growing trivalent metallic ions (mainly Fe3+, Cr3+ and Al3+) in the solution to form stabilized complex compounds, thus improving the stability of crystal rapid growth and crystal's optical quality.

Description

The quick growth method of a kind of heavy caliber potassium dihydrogen phosphate single crystal

Technical field

The present invention relates to crystal growth, especially relate to heavy caliber potassium primary phosphate (KH ₂PO ₄, be called for short KDP) and the quick growth method of single crystal.

Background technology

The KDP crystal is a kind of good nonlinear optical material, be mainly used in two, three, four frequencys multiplication of laser, especially fine large size KDP crystal has been classified as unique Applied Materials of laser fusion frequency inverted at present in the world, also is the hot subject of current international Study on Crystals Growth.So far great majority still prolong with traditional method and carry out single crystal growing, though usually the falling temperature method of employing, constant temperature flow method, evaporation at constant temperature make-up solution method etc. also to grow quality better, larger-size monocrystalline, but the speed of growth is too slow, growth cycle is oversize, and cost is too high, and efficient is too low.

For the large-sized KDP seed crystal that the obtains heavy caliber crystal that is used to grow, the investigator adopts two kinds of methods both at home and abroad for a long time, a kind of is to adopt repeatedly to cultivate the size that the expanding species method enlarges the KDP bore, but the efficient of this repeatedly expanding species is limited, people such as J.W.Mullin are at J.Appl.Chem, and 20,153 (1970) point out because the KDP crystal respectively only increases along Z-direction basically to process of growth, and the xy bore seldom enlarges, even also dwindles to some extent at later stages.So expanding species method complicated operation repeatedly, efficient is low, and the cycle is long.Another kind method is people's reports on " silicate journal " 1984 the 12 volume third phases such as Su Genbo, with four Z cut with 45 ° cut the KDP wafer and be spliced in parallel with each other and carry out single crystal growing, through repeatedly eliminating the normal awl monocrystalline that the method for piecing together the awl growth also only grows 80 * 80 (mm) bore.Experiment shows that the number of wafers that is used to splice is many more, and size is big more, and success ratio is low more, is difficult to reach the degree of practicability.In sum, carry out heavy caliber KDP crystal growth, at first will obtain bigbore seed crystal, just must carry out the method for these two kinds of long period poor efficiency of above-mentioned method of expanding species repeatedly or seed crystal splicing method by traditional growth method.Even obtained the seed wafer of large-size, the final crystal that also will just can grow useful size through the above time of a year and a half can not satisfy far away at present in the world to KDP crystalline demand.

The crystal method for fast growing has obtained very big development in recent years, U.S. LLNL adopt the quick growing technology of some seed crystal realized first large size (the quick growth of 40～50cm) KDP, its Z to and X, Y reaches 10～20mm/d to the speed of growth.But the raw materials used purity of this method is very high, and cost is also long thereupon to raise, and solution is wanted circulating filtration in crystal growing process, the cost of equipment height.

Summary of the invention

Purpose of the present invention just is to propose a kind of new KDP crystal method for fast growing, by add sequestrant sulphosalicylic acid in a small amount in saturated solution, making the trivalent metal ion that influences crystal quick growth under high degree of supersaturation in the solution by complex reaction (mainly is Fe ³⁺, Cr ³⁺, Al ³⁺) form stable complex compound, thus the crystal stability and the crystalline optical quality of growth fast improved, make under the raw material condition that crystal is grown in the common slow growth groove fast and purity is lower and also can realize.

The present invention is with the aqueous solution cooling method heavy caliber KDP crystal of growing fast, but changed in the past only in the way of Z direction growth, adopts additive promoting the KDP crystal along X, Y, and three directions of Z are growth fast simultaneously.This method is to be primary solvent with the redistilled water, adds excessive solid top grade KDP raw material, is mixed with supersaturated solution under 35 ~ 80 ℃, and (its molecular formula is C to add the sulphosalicylic acid of 0.1～2wt% in the saturated solution ₇H ₆O ₆S2H ₂O) additive is used tradition and is hung after brilliant method accurately measures the saturation point of saturated solution, through 18～24 hours seed crystals to be put of ultra-fine micropore (aperture is 0.15 μ) membrane filtration back balance.The little wafer that seed crystal adopts the transparent 90 ° of Z of high-quality to cut, with the secondary aquae destillata polish on the silk dry after, the crystalline substance that carries that is fixed on growth up with AB glue coils.Putting into baking oven is preheated to solution and puts into above-mentioned growth from solution again after synthermal.Initial degree of supersaturation maximum can reach 6.5 ℃, growth 24h when being about to solution and cooling to rapidly than low 6.5 ℃ of saturation point, general subsequently initial growth stage cooling every day amount is advisable for 0.3～0.5 ℃, and along with crystalline is grown up fast, cooling every day amount can increase to about 2 ℃.Undertaken by above method, its KDP crystalline X, Y, the average day growth speed of three directions of Z can reach 7～11 (mm).

We have measured the metastable zone width of the KDP saturated solution of the sulphosalicylic acid that adds different additions, drawing best addition is 1wt%, want wide about 6 ℃ with the average of KDP saturated solution pure under the uniform temp, the stability that solution is described has improved, and the quick growth of crystal can be carried out under high degree of supersaturation.

We have also measured the content of metal ion in the crystal, crystalline sees through spectrum and crystalline damage threshold, KDP crystal contrast with slow growth, after finding to add sulphosalicylic acid, crystal each to fast growth an order of magnitude, metal ion content reduces half, crystalline sees through spectral transmittance and raises, special in short wavelength's ultraviolet region, the crystalline damage threshold is about 15J/cm after annealing in 150～160 ℃ of warm areas ²(1.064 μ, 1ns) with at a slow speed quite, reach service requirements.

The present invention has overcome the KDP crystal usually only in the growth of Z direction, and the very slow problem of long speed.Changed the habitual in the past conventional practice that need obtain bigbore seed crystal by the method for expanding species or polylith seed crystal splicing repeatedly, with little seed crystal method for it; It is slow to the speed of growth simultaneously also to change Z, the state that X, Y are long hardly.Demonstrate several big advantages add sulphosalicylic acid in the saturated solution of KDP after: one, crystal are grown in fast in the common crystal growth groove and can carry out, and need not circulation filter; Its two, the effect of the low temperature high saturation that the solubleness of the KDP during than pure state in water can obtain is convenient to the operation of process of growth.Its three, the most important thing is to play KDP Growth Habit regulating effect, promote KDP (x, y, z) three directions growths (promptly realizing comprehensive growth) fast simultaneously.High 5 ~ 10 times growth efficiency of ratio traditional technology method growth KDP crystal that under same appointed condition, can obtain.Thereby shortened growth cycle greatly; Its four, the crystal optics quality is unaffected, crystalline ultraviolet through performance is improved, and can better be applied to high frequency double laser.

The present invention be advantageous in that and adopt little seed crystal to carry out the heavy caliber crystal growth, can settle at one go, grow needed seed size or available crystal apace, easy to operate, (x=y=z) the square crystal utilization ratio height that grows simultaneously because seed product size is very little, becomes awl short time of recovery, therefore the extension of the defective of seed crystal itself is few, has saved the solid material in the solution.

Embodiment

Get secondary aquae destillata 3000ml and add about 1500 gram AR level KDP raw materials, add 45 gram sulphosalicylic acids then, in with 5000ml ground sealing glass cylinder, be warming up to 70 ℃, constant temperature stirred after 24 hours, after treating that the KDP raw material dissolves fully, accurately to measure the saturation point of solution be 65.2 ℃ with hanging brilliant method in cooling.With solution at high temperature by the aperture be warming up to behind the membrane filtration of 0.15 μ 75 ℃ than saturation point high 10 ℃ down overheated 24h treat down crystal seed, this helps to improve spontaneous crystallization in stability of solution and the minimizing crystal growing process.Get the square little wafer of 8 * 8 * 3 (mm) size as seed crystal after cutting with transparent complete 90 ° of Z of KDP crystal, on the wetting silk of secondary aquae destillata, polish and dry, being fixed on the fine synthetic glass with AB glue carries on the brilliant dish, (001) faces up, after putting into the baking oven preheating of about 75 ℃ of constant temperature, put into above-mentioned saturated solution again and grow, and cool the temperature to 58.7 ℃ rapidly than low 6.5 ℃ of saturation point temperature, open the Crystal Rotation device, 30 rev/mins rotating speed makes the (00! of seed crystal ) face begins into awl, crystal recovers again.After 24 hours along with crystalline is grown up, reduce to 53.6 ℃ gradually with 0.3～2 ℃/day cooling amount, crystal is taken out in quick growth through 6 days when extracting solution equilibria to room temperature at last out, obtain the square transparent heavy caliber KDP crystal that 52 * 48 * 70 (mm) weight reaches 290 grams.

Claims

1. quick growth method of heavy caliber potassium dihydrogen phosphate single crystal is characterized in that:

(1) consumption of additive sulphosalicylic acid in solution is 1wt%;

(2) initial degree of supersaturation can reach 6～7 ℃;

(3) KDP crystalline X, Y, the average day growth speed of three directions of Z is 7～11mm.

2. the quick growth method of heavy caliber KDP single crystal as claimed in claim 1 is characterized in that: see through spectral transmittance at short wavelength's ultraviolet region crystalline and raise.

3. the quick growth method of heavy caliber KDP single crystal as claimed in claim 1 is characterized in that: after the annealing, crystal is 15J/cm at the laser damage threshold of wave band 1.064 μ and pulsewidth 1ns in 150～160 ℃ of warm areas ²