Title of Invention	"AN IMPROVED PROCESS FOR THE PREPARATION OF POTASSIUM TITANYL PHOSPHATE CRYSTALS USEFUL AS AN UNIQUE NONLINEAR OPTICAL MATERIAL"
Abstract	This invention relates to an improved process fro the preparation of potassium titanyl phosphate (KTP) crystals useful as an unique nonlinear optical material. An improved process for the preparation of potassium titanyl phosphate (KTP) crystals useful as an unique nonlinear optical material which comprises mixing Kth PO4 & TiO2 and NaF & KH2 PO4 in equimolar proportion heating the mixture at a temperature in the range of 1090-1125°C and maintaining the mixture at the temperature for a period in the range of 2-24h for homogenization, cooling the homogenized mixture at a rate in the range of 4-150°C/day and separating potassium titanyl phosphate crystal by washing in water.

Title of Invention

"AN IMPROVED PROCESS FOR THE PREPARATION OF POTASSIUM TITANYL PHOSPHATE CRYSTALS USEFUL AS AN UNIQUE NONLINEAR OPTICAL MATERIAL"

Abstract

This invention relates to an improved process fro the preparation of potassium titanyl phosphate (KTP) crystals useful as an unique nonlinear optical material. An improved process for the preparation of potassium titanyl phosphate (KTP) crystals useful as an unique nonlinear optical material which comprises mixing Kth PO4 & TiO2 and NaF & KH2 PO4 in equimolar proportion heating the mixture at a temperature in the range of 1090-1125°C and maintaining the mixture at the temperature for a period in the range of 2-24h for homogenization, cooling the homogenized mixture at a rate in the range of 4-150°C/day and separating potassium titanyl phosphate crystal by washing in water.

Full Text	This invention relates to an improved process for the preparation of potassium titanyl phosphate (KTP) crystals useful as an unique nonlinear optical material. Potassium titanyl phosphate (KTP) has been demonstrated (J.D.Bierlein and T.E. Gier, US patent No. 3949323 1976): F.C. Zusmteg, J.D. Bierlein and T.E.Gier, J. Appl. Phys. 47 (1976) 4980) to be a useful nonlinear optical material for second harmonic generation (SHG) applications. It is particularly attractive for this application because of its high nonlinear optical coefficient, high optical damage threshold and low phase matching properties (J.D. Bierlein and C.B. Arweiler, Appl. Phys. Lett. 49 (1986) 917). Its large electrooptic r coefficients and low dielectric constant make it attractive for various electrooptic applications such as modulators and Q switches. Recently KTP is also reported as an interesting material for waveguide purposes (J.D. Bierlein, A. Ferretti, L.H. Brixner and W.Y. Hsu, Appl. Phys.Lett. 50(1987) 1216) and as a self - 3+ frequency doubling laser crystal, when doped with 50-500ppm Cr (N.Y. Chou, E.B. Koker, N.P.Barnes and G.M. Loicano in : Tech. Digest Advanced solid State Lasers, Salt Lake City, Ut March 1990 Paper MA4-1). KTP also has an electrooptic waveguide modulator figure of merit that is nearly double that of any other inorganic material (J.D. Bierlein and C.B. Arweiler, Appl. Phys. Lett 49 (1986) 917). It is non-hygroscopic and physically and chemically stable. An additional advantage of KTP is its relatively high laser damage threshold which is approximately 0.3GW/cm2 for pulse width of 30-200ns (R.F. Belt, G. Gashurov and Y.S. Lin, Laser Focus 21 (1985) 110). KTP decomposes on melting and hence normal melt process cannot be used to grow this material. The growth of good quality KTP crystals is difficult. A good quality crystal contains fewer (or no) planar defects, line defects and impurities. It is difficult to get good quality crystals using K6 P4 013 or tungstate flux due to flux inclusion, glass formation, high viscosity of the flux and hence very slow cooling rate is required. The KTP crystals can be grown by the flux and hydrothermal methods (G.O.Stucky, M.L.F. Philips and T.E.Gier Chem. Mater. 1(1989) 492, J.C. Jacco, G.M. Liocano, M. Jaso, G. Mizell and B. Greenberg, J. Cryst. Growth 70 (1984) 484; A.A. Ballman, H.Brown, 0. Olsan and C.E. Rice, J. Cryst. Growth 75 (1986) 390). Hydrothermal method of growth. In 1981 the Airtron Company started to produce KTP crystals commercially by a hydrothermal process developed by the du Pont. o The crystals are grown at a temperature of 600 C and pressure of about 2 kilobars. This technique requires very sophisticated and expensive pressure equipment. The as-grown crystals contain the problem of OH incorporation in the crystal lattice. The rate of growth of KTP crystals by the hydrothermal method is about 1.5 mm per day (R.A. Laudise, R.J. Cava and A.J. Caporaso, J. Cryst. Growth 74 (1986) 275). Flux method In this method KTP is grown from a high temperature solution using a suitable flux (Jacco et al. J. Cryst. Growth 70 (1984) 484; Ballman et al. J. Cryst. Growth 75 (1986) 390; Bordui et al. J. Cryst. Growth 84 (1987) 403; Bolt et al. J. Cryst. Growth 112 (1991) 773). The commonly used flux for KTP growth is K6 P4 O13 This may be modified with substances like WO3 , MoO3 or a sulphate. The KTP crystals are commercially grown in China (Foetsy Syon) Russia (Xovosibirsk) and USA (du Pont; Crystal Inc.). The flux and hydrothermal growth of KTP are patented by Gier (Europ. Pat. No. 0004-974 (1979); US Pat. No. 4305-978 (1981). A significant advantage of the process employing a flux is that it operates at atmospheric pressures and hence does not require sophisticated pressure equipments as in the hydrothermal growth. The studies of Bordui et al and Jacco et al. on KTP solution in K6P4013 indicated that the most important disadvantage of phosphate flux is its high viscosity at low temperatures and one has to cool down very slowly during growth. Fast cooling leads to glass formation and do not yield crystals. When crystals are grown using K6P4013 as a flux, the system is prone to spurious nucleation which can be avoided by extensive stirring and maintaining a uniform temperature. High level temperature control are required to avoid growth striations and flux inclusions. The presence of OH inclusions deteriorates the NLO properties (W.T. Theis, G.B. Norris and M.D. Porter, Appl. Phys. Lett., 46 (1984) 1033). In 1986 Ballman et al. published data on the growth of KTP single crystals from solutions in a flux system consisting of K20-P205 -WO3 with 3:1:3 molar ratio between the three oxides. According to the above authors this flux system has the advantage over K6 P4 013 flux with the lower viscosity of its solution of KTP. But the main disadvantage of this flux is that during growth a considerable tungsten inclusion take place and the crystals are coloured. The crystals grow very slowly (about 1.5 mm per day) in both phosphate and tungstate fluxes. In the case of phosphate flux fast cooling leads to glass formation. These crystals are used for second harmonic generation (SHG) applications. It has high nonlinear optical coefficients and high optical damage threshold. The crystals are very useful for various electrooptic applications such as modulators and Q-switches. Under these circumstances there is a need to develop a process for the preparation of such crystals which does not have the drawbacks of the hitherto known processes discussed above. The main object of the present invention is to provide an improved process for the preparation of potassium titanyl phosphate (KTP) crystals useful as an unique nonlinear optical material which overcomes the drawbacks of the hitherto known processes. The invention is based on our finding that potassium sodium phosphate fluoride (KNaPO3F) can be used as flux in the process for the preparation of KTP crystals. It is observed by us that the viscosity of KNaPO3F is lower than that of the conventional flux K6P4013 . Further,it is also observed that the mixture of and KNaPO3F melts and on cooling the melt the crystals are formed. The solubility of KTP in KNaPO3 F is higher than that in the conventional flux K6 P4 013 which facilitates fast growth of KTP. The KTP has been found to be the single stable phase over the entire cooling range studied. The following equation gives a general description of our growth process. KH2 PO4 + TiO2 > KTiOPO4 + H2 O (1) NaF + KH2 PO4 > KNaPO F+ H 0 (2) KTP has been prepared by reacting TiO2 with KH2 PO4 . The flux was obtained from KH2 PO4 and NaF in the ratio 1:1. The reactions (1) and (2) can be effected simultaneously also. Accordingly the present invention provides an improved process for the preparation of potassium titanyl phosphate (KTP) crystals useful as an unique nonlinear optical material which comprises mixing stoichometric quantities of KH2 PO4 & TiO2 and NaF & KH2 PO4 heating the mixture at a temperature in the of 1090-11250C and maintaining the mixture at the temperature for a period in the range of 2-24h for homogenisation, cooling the homogenised mixture at a rate in the range of 4-1500 C/day and separating potassium titanyl phosphate by washing in water crystals The KTP crystallises during the cooling down period in the o temperature 1100-1020 C. To get a single domain crystal and to prevent crystals from microcracking at the transition temperature o 934 C, the crystals are to be slowly cooled to a temperature in the range of 1020-9000C. In the present invention, the crystals are grown by spontaneous nucleation (without the use of seed crystals) in platinum crucibles prefereably of 50ml size. Hence the size of the crystals is limited. It is possible to grow large crystals with still better perfection by using large platinum crucibles of the size about 300 ml and with a cooling rate of o about 4 C per day and also by using seed crystals. The starting materials KH2 PO4 and TiO2 are weighed in stoichiometric ratios as per equation (1) and mixed well in an agate which is the KTP reaction mixture. Again KH2 PO4 and NaF are weighed in stoichiometric ratios (for the flux) as per equation (2) and mixed well. The KTP reaction mixture is then mixed well with different weight percentages of the flux. From several experiments of different solvent and solute compositions it is found that 10-30 weight percentage of solvent give good crystals. The mixture of KTiOPO4 and KNaPO3 F is taken in an open platinum crucible. It is then heated to a temperature in the range of 1090-11250C at soaked for a period in the range of 2-24h for homogenisation and then cooled at a rate in the range 4- 1500C/day. The growth period depends on the cooling rate. eg. 1 o day for a cooling rate of 120 C per day. The as-grown crystals are removed by dissolving the flux in ordinary water. The dimensions of the crystals depends on the cooling rate and the size of the platinum crucible. The crystals prepared according to the present invention are transparent and free of OH inclusions. The crystals so prepared show nonlinear optical properties. The details of the invention are given in the examples provided below by way of illustration only and therefore should not be construed to limit the scope of the invention. Example 1 KTP reaction mixture was prepared by mixing 6.8045g of KH2 PO4 with 3.995g of TiO2 in an agate. 4.199g of NaF was mixed with 13.609g of KDP to form the reaction mixture of the flux. 3.7g of the flux (25 wt.% of the total weight) is mixed with the o above KTP reaction mixture and heated to 1100 C for 2h for o homogenisation. Then the reaction mixture is cooled to 900 C at the rate of 5 C/h. Then the mixture is cooled to room temperature at the rate of 50 C/h. Crystals formed are separated from the flux by washing in water. Example 2 lOg of KTP reaction mixture (KDP+TiO2 ) was mixed with 1.7646g (15 wt.% of the total weight) of the flux mixture (NaF+KDP) in an agate. The mixture was heated to 11000C for 2h and then cooled to 9000C at the rate of 50C/h. After cooling to room temperature at the rate of 100 C/h the crucible is taken out and the crystals are separated from the flux by washing in water. Comparison of the crystals formed by the methods using different flux is given in the Table 1 shown below. Table 1 (Table Removed) (Spontaneous nucleation)The main advantages of the process of the present invention are: 1. Low viscosity of the solution of KTP in the flux KNaPO3 F. Hence very slow cooling rate is not needed for growth of the crystals. In the conventional flux growth method the approximate 3 size of the spontaneously grown crystal is about 26 X 15 x 7 mm using a cooling rate of 4 C per day in the crystallisation range 950-9000C (about 13 days) In the present invention one can grow 3 crystals up to the size 5X4X2 mm in a day by giving a cooling o rate of 1200C per day. 2. Because of the above advantage (Table 1) within a day 3 transparent crystals of size up to 5 X4X2 mm can be obtained o with a higher cooling rate of 120 C per day in the range 1100- 10200C. Higher cooling rate (rapid cooling) does not lead to glass formation unlike in the conventional method using K6P4O613 as flux. 3. The rate of growth of crystals according to the process of present invention is much higher than process hitherto known. 4. The process of present invention employing KNaPO3 F as flux does not result in glass formation. 5. Since KNaPO3 F used as flux is soluble in water, the separation of the crystals formed from the flux is easy. We claim: 1. An improved process for the preparation of potassium titanyl phosphate (KTP) crystals useful as an unique nonlinear optical material which comprises mixing stoichometric quantities of KH2PO4 & TiO2 and NaF & KH2 PO4 heating the mixture at a tempera-ture in the range of 1090-11250C and maintaining the mixture at the temperature for a period in the range of 2-24h for homogeni- sation, cooling the homogenised mixture at a rate in the range of 4-1500C/day and separating the crystals formed by dissolving the flux in water. 2. An improved process as claimed in claim 1 wherein the o temperature of crystallisation is in the range of 1100-1020 C. 3. An improved process as claimed in claims 1 & 2 wherein the mixture is slowly cooled to a temperature in the range of 1020- 9000C. 4. An improved process for the preparation of potassium titanyl phosphate (KTP) crystals useful as an unique nonlinear optical material substantially as herein described with reference to the examples.

Full Text

This invention relates to an improved process for the preparation of potassium titanyl phosphate (KTP) crystals useful as an unique nonlinear optical material.
Potassium titanyl phosphate (KTP) has been demonstrated (J.D.Bierlein and T.E. Gier, US patent No. 3949323 1976): F.C. Zusmteg, J.D. Bierlein and T.E.Gier, J. Appl. Phys. 47 (1976) 4980) to be a useful nonlinear optical material for second harmonic generation (SHG) applications. It is particularly attractive for this application because of its high nonlinear optical coefficient, high optical damage threshold and low phase matching properties (J.D. Bierlein and C.B. Arweiler, Appl. Phys. Lett. 49 (1986) 917). Its large electrooptic r coefficients and low dielectric constant make it attractive for various electrooptic applications such as modulators and Q switches. Recently KTP is also reported as an interesting material for waveguide purposes (J.D. Bierlein, A. Ferretti, L.H. Brixner and
W.Y. Hsu, Appl. Phys.Lett. 50(1987) 1216) and as a self -
3+ frequency doubling laser crystal, when doped with 50-500ppm Cr
(N.Y. Chou, E.B. Koker, N.P.Barnes and G.M. Loicano in : Tech. Digest Advanced solid State Lasers, Salt Lake City, Ut March 1990 Paper MA4-1). KTP also has an electrooptic waveguide modulator figure of merit that is nearly double that of any other inorganic material (J.D. Bierlein and C.B. Arweiler, Appl. Phys. Lett 49 (1986) 917). It is non-hygroscopic and physically and chemically
stable. An additional advantage of KTP is its relatively high

laser damage threshold which is approximately 0.3GW/cm2 for
pulse width of 30-200ns (R.F. Belt, G. Gashurov and Y.S. Lin, Laser Focus 21 (1985) 110).
KTP decomposes on melting and hence normal melt process cannot be used to grow this material. The growth of good quality KTP crystals is difficult. A good quality crystal contains fewer (or no) planar defects, line defects and impurities. It is
difficult to get good quality crystals using K6 P4 013 or tungstate flux due to flux inclusion, glass formation, high viscosity of the flux and hence very slow cooling rate is required. The KTP crystals can be grown by the flux and hydrothermal methods (G.O.Stucky, M.L.F. Philips and T.E.Gier Chem. Mater. 1(1989) 492, J.C. Jacco, G.M. Liocano, M. Jaso, G. Mizell and B. Greenberg, J. Cryst. Growth 70 (1984) 484; A.A. Ballman, H.Brown, 0. Olsan and C.E. Rice, J. Cryst. Growth 75 (1986) 390).
Hydrothermal method of growth.
In 1981 the Airtron Company started to produce KTP crystals
commercially by a hydrothermal process developed by the du Pont.
o The crystals are grown at a temperature of 600 C and pressure of
about 2 kilobars. This technique requires very sophisticated and expensive pressure equipment. The as-grown crystals contain the problem of OH incorporation in the crystal lattice. The rate of growth of KTP crystals by the hydrothermal method is about 1.5 mm per day (R.A. Laudise, R.J. Cava and A.J. Caporaso, J. Cryst. Growth 74 (1986) 275).
Flux method
In this method KTP is grown from a high temperature solution using a suitable flux (Jacco et al. J. Cryst. Growth 70 (1984) 484; Ballman et al. J. Cryst. Growth 75 (1986) 390; Bordui et al. J. Cryst. Growth 84 (1987) 403; Bolt et al. J. Cryst. Growth 112
(1991) 773). The commonly used flux for KTP growth is K6 P4 O13 This may be modified with substances like WO3 , MoO3 or a sulphate.
The KTP crystals are commercially grown in China (Foetsy Syon) Russia (Xovosibirsk) and USA (du Pont; Crystal Inc.). The flux and hydrothermal growth of KTP are patented by Gier (Europ. Pat. No. 0004-974 (1979); US Pat. No. 4305-978 (1981).
A significant advantage of the process employing a flux is that it operates at atmospheric pressures and hence does not require sophisticated pressure equipments as in the hydrothermal growth. The studies of Bordui et al and Jacco et al. on KTP
solution in K6P4013 indicated that the most important
disadvantage of phosphate flux is its high viscosity at low temperatures and one has to cool down very slowly during growth. Fast cooling leads to glass formation and do not yield crystals.
When crystals are grown using K6P4013 as a flux, the system is prone to spurious nucleation which can be avoided by extensive stirring and maintaining a uniform temperature. High level temperature control are required to avoid growth striations and
flux inclusions. The presence of OH inclusions deteriorates the NLO properties (W.T. Theis, G.B. Norris and M.D. Porter, Appl. Phys. Lett., 46 (1984) 1033).
In 1986 Ballman et al. published data on the growth of KTP single crystals from solutions in a flux system consisting of
K20-P205 -WO3 with 3:1:3 molar ratio between the three oxides.
According to the above authors this flux system has the advantage
over K6 P4 013 flux with the lower viscosity of its solution of KTP. But the main disadvantage of this flux is that during growth a considerable tungsten inclusion take place and the crystals are coloured. The crystals grow very slowly (about 1.5 mm per day) in both phosphate and tungstate fluxes. In the case of phosphate flux fast cooling leads to glass formation.
These crystals are used for second harmonic generation (SHG) applications. It has high nonlinear optical coefficients and high optical damage threshold. The crystals are very useful for various electrooptic applications such as modulators and Q-switches. Under these circumstances there is a need to develop a process for the preparation of such crystals which does not have the drawbacks of the hitherto known processes discussed above.
The main object of the present invention is to provide an improved process for the preparation of potassium titanyl phosphate (KTP) crystals useful as an unique nonlinear optical material which overcomes the drawbacks of the hitherto known processes.
The invention is based on our finding that potassium sodium
phosphate fluoride (KNaPO3F) can be used as flux in the process

for the preparation of KTP crystals. It is observed by us that
the viscosity of KNaPO3F is lower than that of the conventional

flux K6P4013 . Further,it is also observed that the mixture of
and KNaPO3F melts and on cooling the melt the crystals are
formed. The solubility of KTP in KNaPO3 F is higher than that in the conventional flux K6 P4 013 which facilitates fast growth of KTP. The KTP has been found to be the single stable phase over the entire cooling range studied. The following equation gives a general description of our growth process.
KH2 PO4 + TiO2 > KTiOPO4 + H2 O (1)

NaF + KH2 PO4 > KNaPO F+ H 0 (2)

KTP has been prepared by reacting TiO2 with KH2 PO4 . The flux

was obtained from KH2 PO4 and NaF in the ratio 1:1. The reactions

(1) and (2) can be effected simultaneously also.
Accordingly the present invention provides an improved process for the preparation of potassium titanyl phosphate (KTP) crystals useful as an unique nonlinear optical material which
comprises mixing stoichometric quantities of KH2 PO4 & TiO2 and NaF & KH2 PO4 heating the mixture at a temperature in the

of 1090-11250C and maintaining the mixture at the temperature for
a period in the range of 2-24h for homogenisation, cooling the

homogenised mixture at a rate in the range of 4-1500 C/day and

separating potassium titanyl phosphate by washing in water crystals The KTP crystallises during the cooling down period in the
o temperature 1100-1020 C. To get a single domain crystal and to
prevent crystals from microcracking at the transition temperature
o 934 C, the crystals are to be slowly cooled to a temperature in the range of 1020-9000C. In the present invention, the crystals are grown by spontaneous nucleation (without the use of seed crystals) in platinum crucibles prefereably of 50ml size. Hence the size of the crystals is limited. It is possible to grow large crystals with still better perfection by using large platinum
crucibles of the size about 300 ml and with a cooling rate of
o about 4 C per day and also by using seed crystals.
The starting materials KH2 PO4 and TiO2 are weighed in

stoichiometric ratios as per equation (1) and mixed well in an
agate which is the KTP reaction mixture. Again KH2 PO4 and NaF are

weighed in stoichiometric ratios (for the flux) as per equation (2) and mixed well. The KTP reaction mixture is then mixed well with different weight percentages of the flux. From several experiments of different solvent and solute compositions it is found that 10-30 weight percentage of solvent give good
crystals. The mixture of KTiOPO4 and KNaPO3 F is taken in an open

platinum crucible. It is then heated to a temperature in the
range of 1090-11250C at soaked for a period in the range of 2-24h
for homogenisation and then cooled at a rate in the range 4-
1500C/day. The growth period depends on the cooling rate. eg. 1
o day for a cooling rate of 120 C per day. The as-grown crystals
are removed by dissolving the flux in ordinary water. The dimensions of the crystals depends on the cooling rate and the size of the platinum crucible.
The crystals prepared according to the present invention are transparent and free of OH inclusions. The crystals so prepared show nonlinear optical properties.
The details of the invention are given in the examples provided below by way of illustration only and therefore should not be construed to limit the scope of the invention.
Example 1
KTP reaction mixture was prepared by mixing 6.8045g of
KH2 PO4 with 3.995g of TiO2 in an agate. 4.199g of NaF was mixed with 13.609g of KDP to form the reaction mixture of the flux.
3.7g of the flux (25 wt.% of the total weight) is mixed with the
o above KTP reaction mixture and heated to 1100 C for 2h for
o homogenisation. Then the reaction mixture is cooled to 900 C at
the rate of 5 C/h. Then the mixture is cooled to room temperature
at the rate of 50 C/h. Crystals formed are separated from the
flux by washing in water.
Example 2
lOg of KTP reaction mixture (KDP+TiO2 ) was mixed with

1.7646g (15 wt.% of the total weight) of the flux mixture
(NaF+KDP) in an agate. The mixture was heated to 11000C for 2h

and then cooled to 9000C at the rate of 50C/h. After cooling to
room temperature at the rate of 100 C/h the crucible is taken out and the crystals are separated from the flux by washing in water.
Comparison of the crystals formed by the methods using different flux is given in the Table 1 shown below.
Table 1
(Table Removed)
(Spontaneous nucleation)The main advantages of the process of the present invention are:
1. Low viscosity of the solution of KTP in the flux KNaPO3 F. Hence very slow cooling rate is not needed for growth of the crystals. In the conventional flux growth method the approximate 3 size of the spontaneously grown crystal is about 26 X 15 x 7 mm using a cooling rate of 4 C per day in the crystallisation range 950-9000C (about 13 days) In the present invention one can grow 3 crystals up to the size 5X4X2 mm in a day by giving a cooling o rate of 1200C per day.
2. Because of the above advantage (Table 1) within a day
3 transparent crystals of size up to 5 X4X2 mm can be obtained o with a higher cooling rate of 120 C per day in the range 1100- 10200C. Higher cooling rate (rapid cooling) does not lead to glass formation unlike in the conventional method using K6P4O613 as flux.
3. The rate of growth of crystals according to the process of
present invention is much higher than process hitherto known.
4. The process of present invention employing KNaPO3 F as flux does not result in glass formation.
5. Since KNaPO3 F used as flux is soluble in water, the separation of the crystals formed from the flux is easy.

We claim:
1. An improved process for the preparation of potassium titanyl phosphate (KTP) crystals useful as an unique nonlinear optical material which comprises mixing stoichometric quantities of
KH2PO4 & TiO2 and NaF & KH2 PO4 heating the mixture at a tempera-ture in the range of 1090-11250C and maintaining the mixture at
the temperature for a period in the range of 2-24h for homogeni-
sation, cooling the homogenised mixture at a rate in the range of
4-1500C/day and separating the crystals formed by dissolving the
flux in water.
2. An improved process as claimed in claim 1 wherein the
o temperature of crystallisation is in the range of 1100-1020 C.
3. An improved process as claimed in claims 1 & 2 wherein the
mixture is slowly cooled to a temperature in the range of 1020-
9000C.
4. An improved process for the preparation of potassium titanyl
phosphate (KTP) crystals useful as an unique nonlinear optical
material substantially as herein described with reference to the
examples.

Documents:

640-del-1996-abstract.pdf

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640-del-1996-correspondence-others.pdf

640-del-1996-correspondence-po.pdf

640-del-1996-description (complete).pdf

640-del-1996-form-1.pdf

640-del-1996-form-13.pdf

640-del-1996-form-2.pdf

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Patent Number

217730

Indian Patent Application Number

640/DEL/1996

PG Journal Number

17/2008

Publication Date

25-Apr-2008

Grant Date

28-Mar-2008

Date of Filing

27-Mar-1996

Name of Patentee

COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH

Applicant Address

RAFI MARG, NEW DELHI-110001, INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	SUBHADRA SUMA	REGIONAL RESEARCH LABORATORY, TRIVANDRUM, INDIA.
2	NARAYANA IYER SANTHA	REGIONAL RESEARCH LABORATORY, TRIVANDRUM, INDIA.
3	MAILADIL THOMAS SEBASTIAN	REGIONAL RESEARCH LABORATORY, TRIVANDRUM, INDIA.

PCT International Classification Number

B01D 9/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA