MXPA97002816A

MXPA97002816A - Laser crystal of oxyhalogenuro impurified with elements of land ra

Info

Publication number: MXPA97002816A
Application number: MXPA/A/1997/002816A
Authority: MX
Inventors: Edward Dickinson James Jr
Original assignee: Corning Incorporated
Priority date: 1996-04-17
Filing date: 1997-04-16
Publication date: 1998-10-30

Abstract

The oxyhalogenide laser crystal doped with rare earth elements of the present invention comprises the replacement of oxygen by fluorine in crystals having the general molar composition of 50% SiO2, 25% CaO, 25% A12O3, for improve the distribution of rare earth doping agents in the crystal, the general molar mixture compositions of the invention vary from about 45 to 70% SiO2, from 15 to 35% CaO, from 10 to 25% of A12O3, from 4 to 15 % of A12F6, and 0.001 to 2% of ErsO3, this incorporation of fluorine in the 25iO2.A1sO3O crystal system provides erbium doped laser crystals that have a mix content of Er2O3 of 0.01 mole percent of Er2O3 at 1.2 mole percent of Er2O3 (500 ppm of Er2O3 to 5.68% by weight of Er2O3), which show little or no concentration extinction and exhibit useful fluorescence lifetimes of approximately 6 milliseconds (ms) or greater

Description

nRTSTRL OF LIFlSER OF OXIHfILOGENURO IMPURIFIED WITH ELEMENTS OF RARE LANDS FIELD OF THE INVENTION-1 This invention relates to oxyhalogenide laser crystals impuried with rare earth elements.

BACKGROUND OF THE INVENTION It is known from the prior art that laser crystals can be produced by impregnation of silica glass with elements of rare earths. The laser property of such laser crystals doped with rare earth elements 5 is derived from the amplification of light that is achieved by the stimulated emission of the excited ions of the rare earth elements contaminated in the crystal and depends on the time of the fluorescence of the ions irnpuri Lcados. It is also known that the output of the being of a laser crystal depends on the number of rare earth ions present in the crystal. The problem in the prior art has been that a maximum usable concentration of rare earth ions in a laser crystal is rapidly reached, due to the phenomenon of concentration extinction. Concentration extinction is due to the nonradioactive disintegration of the excited rare earth ions that are too close to their non-excited, rare earth excited ions. Excited rare earth ions transfer energy to non-excited ions of rare earths immediately adjacent to the polo d pole coupling, resulting in no net light output. Insofar as the concentration of rare earth ions in a crystal of l is increased, the rare earth Lones tend to cluster closely together with ions of rare and immediate earths; consequently, a real increase in the excitable rare earth ions responsible for the exit of the being is not reached and the life time of the fluorescence of the tier-to-rage ions is reduced. The problem faced by the prior art has been to provide a crystal composition that can be impurified with a relatively high concentration of rare earth ions, without clustering which reduces the lifetime of the fluorescence of the rare earth ions. Currently, erbium is a popular element of the rare earths used in doped laser crystals, since the crystals of being doped with erbium can effectively amplify the wavelength of light 1.55 jirn used in optical telecommunication systems. Neodymium is also used as a rare earth mpurifier in laser crystals. Therefore, the object of the present invention is to provide a crystal of l that solves the problems of the prior art.

RRFVF DESCRIPTION OF THE INVENTION Therefore, it is an object of the present invention to provide a crystal composition which has a relatively high concentration of excoriating erbium-resistant ions which can be used advantageously in laser applications such as pianos and other optical amplifiers. Compact products that require a high concentration of excitable ions for a short path length Briefly, the present invention relates to an oxyhalogenide crystal composition which allows an increased concentration of a rare earth dopant without the detrimental effects of concentration extinction In another aspect, the invention refers to < "? an oxyhalogenide laser crystal composition that advantageously disperses erbium ions to avoid diol-dipole coupling and provide higher luorescence life times. In another aspect, the invention relates to a crystal of l-alkynoxylic acid oxyfluoride. In a further aspect, the invention relates to an oxyfluoride laser crystal having a sufficient fluorine content to inhibit the detrimental effects of concentration extinction.

A further objective of the present invention > describe a method of inhibiting the concentration of rare earth dopant impurifiers in an oxide crystal. The composition of the invention provides an oxyhalogenide crystal with an increased concentration of erbium ion without the detrimental effects of concentration extinction.The oxyhalogenide crystal composition of the invention provides a chemical crystal structure that advantageously disperses the erbium ions away from immediate erbium ions, in order to avoid the dipole-dipole coupling of the concentration extinction that occures when the erbium ions they are located too close to each other. The composition of the invention maximizes the total erbium concentration in the crystal while also increasing the distance between immediate erbium ions. The composition of the invention allows relatively high concentrations of erbium at the same time giving useful life times of luorescence. The oxyfluoride laser crystal of the invention comprises the substitution of oxygen by fluorine in crystals of alurninosilicate. The distribution of the erbium impurifier in the glass is improved by replacing a percentage of the fll ^ O ^ in the general molar composition of the mixture 2Si0s.-Ala.0a- aO with Ols? Fe ,. The general molar composition of the mixture of the invention ranges from about 45 to 70% SiO », 15 to 35% CaO, 10 to 25% Ala03 4 to 15% AlaFß, and 0.001 to 2% Fr_aOa. The blend compositions of the invention melt and form under conditions to provide an oxyfluoride crystal having at least 6% by weight of F.? RFVF? FSCRTPTION OF THE DRAWINGS Figure 1 is a graph of fluorescence lifetime versus erbium ion concentration. Figure 2 is a graph of the lifetime of the fluorescence against the weight percent of analyzed fluorine of doped crystals with 0.01 mole percent of Er_.0! = ?. Figure 1 is a percentage weight chart of the composition of the invention.

DESCRIPTION OF THE INVENTION The oxyhalogenide crystal of the invention comprises the substitution of oxygen by fluorine in crystals having the general molar composition in the mixture of 50% LO ^, 25% CaO, 25% with approximately 11 moles poroLen + or the mixed Ala03. As «Fe, to improve the distribution of erbium impurified in the crystal. The general molar composition of the mixture of the invention ranges from about 45 to 7QX of SJ? A, 15 to 35% of CaO, 10 to 25% of ma03, 4 to 15% of Al?, And 0.001 to 2% of Er ^ Oa. With this incorporation of fluorine into the 2S? O! AAl? 2? 3 CaO crystal system, the inventor has produced erbium doped laser crystals having a content of Ers, 0: -, in the mixture of 0.01 mole percent of Er30a. to 1.2 mole percent of Er2Oa (500 pprn of Fri; Oa a .b (!% by weight of E ^ Oa), which shows little or no concentration extinction and exhibits fluorescence useful life times of approximately 6 milliliters ( rns) or larger The compositions of the mixture of the invention and comparison samples in platinum crucibles covered for about 6 hours at about 1600 ° C were melted, and then poured onto plates of glass to form glass bricks which They measure 10.2 ein x lfl.2 crn x 1.3 cm, which were subsequently annealed to 55 (l ° C.), and they made test samples of the crystal of these glass bricks by scratching and breaking them and then the life time of the fluorescence of the samples after in milliseconds (ms) to determine the properties l ser- of the cri tal. For such crystal formation conditions, a fluorine composition is particularly preferred for the mixture ranging from 5 to 11 mole percent of F5-F (7-15% by weight of F). The fluorine retention rates for the melt blends of the invention vary from 50 to 00%, depending on the initial fluoride concentration and the melting temperature. For example, if 30% by weight of F is mixed, 15% by weight of F is actually determined in the crystal analysis after melting. If 1% by weight of F is mixed, about 7% by weight of F is determined in the crystal analysis after melting. The percentage of F retained in the crystal increases with a reduced melting temperature. The general percentages by weight of the compositions of the mixture of the invention are: 30 -? % by weight of SL02, 25-45% by weight of AlaCa, 10-25% by weight of CaO 0.005-10% by weight of EraO, and 7 35% by weight of F i mixed as Al ^ F ,, ,), with a percentage by weight of fluorine analyzed after melting from 6.2 to 20% by weight of I-, the preferred weight percentages of the compositions of the mixture of the invention are: 30-45% by weight of L02, 30-40% by weight of AlaOg? 15-19% by weight of CaO, 0.005-6% by weight of E a0a, and 9-30% by weight of F 'mixed as Al? Ír?), With a percentage in weight of fluorine analyzed after fusion of 6.5 to 15 weight of F. Table 1 describes mixed compositions of the invention in weight percentage, as they were incorporated in samples 1-10. Table 1 also describes the percentage by weight analyzed of fluorine (F) present in the crystal after fusion and formation of samples 2, 4, 5, 6, 7, 8, 9 and 10. Table 1 includes the percentage by weight of mixed compositions of non-fluorine comparison samples, 11, 12, 13, 14, 15, 16, 17 and 19, which were made and compared with the crystals of the invention containing fluorine. TABLE 1 COMPOSITIONS OF SAMPLES 1-19 IN% FN PFS 1 2 3 4 5 6 7 8 9 10 Si02 39.4 39.4 39.4 39.4 39.4 39.1 38.7 38.3 37.9 37.2 AJA 33.5 33.5 33.5 33.5 33.5 33.1 32.8 32.5 32.2 31.6 CaO 18.4 18.4 18.4 18.4 18.4 18.2 18.0 17.9 17.7 17.4 Er2Oj .0050 .0151 .0251 .0377 .0502 .995 1.97 2.93 3.86 5.68 FOfez.) 14.7 14.6 14.6 14.6 14.6 14.5 14.4 14.2 14.1 13.8 F (Anal.) 7.1 7.7 10.2 8.4 8.3 6.7 7.4 7.5 11 12 13 14 15 16 17 18 19 S02 43.1 43.1 43.1 43.1 43.1 42.7 42.2 39.7 41.3 Al? Oj 36.6 36.6 36.6 36.6 36.6 36.2 35.8 33.7 35.1 CaO 20.1 20.1 20.1 20.1 20.1 19.9 19.7 18.5 19.3 Er2O3 .0055 0165 .0275. 0412 0549 1.09 2.15 4.05 4.21 F (-z.) 0 0 0 0 0 0 0 6.7 0 F (Anal.) 4-9 The fluorescence lifetimes of samples 1-19 were determined by exciting the samples with a beam of 1 Argon ion (514 n). The fluorescent radiation of lac.

Samples were detected with a fo + Ha of Ge and the fluorescence lifetimes were calculated from it, Figure 1 presents the fluorescence life times of the erbium ions from samples 1-19 in milliseconds (rns ) against the density of the erucous impurifier of samples 1-19 in erbium ions per-cm3. Figure 1 clearly shows the higher fluorescence lifetime performance of the invention compared to the non-fluoride samples of the piss by the curve of sample 11 to sample 19. As shown in Figure 1, to the extent that erbium increases from 0.0055% by weight of Er203 in sample 11 to 4.21% by weight of E? -OOp in sample 19 (less than 10 R to more than 10 ^ ions Er / crn3), the fluorescence lifetime declines exponentially from 7.5 ms to 3 ns. On this same scale of erbium concentration, the fluorine-containing samples of the invention have markedly improved life times. The composition of the invention allows higher erbium doping densities of 1030? S / cma at the same time maintaining fluorescence lifetimes of 6 rns and greater. With the composition of the invention, to the extent that the erbium concentration of the sample l (0.005% by weight of mixed EraOa) increases to sample 6 (0.995% by weight of Er- ^ Os, mixed), the time of fluorescence life continues to rise. By increasing the erbium purifier up to 10 years / crn3, the fluorescence lifetime levels leave the scale from 0 to 9 msec, and then decrease to 5 sec with sample 10. The time of *? Da of 6 rnseg of the sample 10 is a u-tilizable level, especially considering the high concentration of erbium. A comparison of sample 18 (4.05% by weight of mixed FraOa, 6.7% by weight of mixed F and 4.9% by weight of F analyzed) with samples 8, 9 and 10 describes that 4.9% by weight of F analyzed in sample 18 is not sufficient to inhibit concentration extinction at such high erbium densities. Table 2 and the graph of Figure 2 show the ratio of the fluorine content analyzed in the crystal after formation to the increased fluorescence lifetimes of the invention and the ability of the invention to inhibit concentration extinction. Table 2 presents the percentage by weight of compositions of the mixtures of samples 20-24 together with samples 15 and 5 of Table 1, all of which have an Er20a composition in the mixture of 0.01 mole percent. Figure 2 clearly shows the ratio of fluorine content of the crystal to its fluorescence lifetime.

TABLE 2 COMPOSITIONS IN% IN WEIGHT THAT HAVE 0.01 MOLES PERCENT OF EraOa 20 21 22 5 23 24 SiO2 43.1 42.0 41.4 39.7 39.4 36.8 35.6 AIA 36.6 35.7 35.1 39.1 33.5 31.3 30.2 CaO 20.1 19.6 19.3 15.6 18.4 17.2 16.6 Er2O3 0549 0535 0527 0506 0502 0469 0453 F (? Z.) 0 4 26 6.98 9.38 14.6 24.9 30 F (Anal.) 3.61 6.17 7.04 10.2 12.8 14.2 To the extent that the percentage by weight of F analyzed in the compositions of the mixture of 0.01 mole porclen or of EraOa of sample 15, which has no F, increases to l sample 21 with 6.17% by weight of F, the Fluorescence lifetime remains stable and on the 6.8-7 ins scale. After, with an increase of approximately 1% by weight of F, the fluorescence lifetime of sample 22 jumps up to 8 ms. Increased life times are also achieved with the weight percentage of F increased from samples 5, 23, and 24. This weight percentage of threshold F of between 6 and 7% correlates with the fluoride content of threshold of between 4.9% by weight of F of the sample 18 and 6.7% by weight of F of the sample 8. The composition of the invention inhibits concentration extinction of the erfcuous ions providing a quimic crystal structure in which the erbium ions are conveniently distributed distanced in between. The fluorine content of the composition of the invention allows an increased concentration of erbium ion at the same time providing fluorescence useful life times. As illustrated in the Composition Weight Percentage Diagram, of FIG. 3, the area of the general crystal oxide composition 101 of the invention is correlated with the general stequiornetpa of the crystalline phases of anorthite (CaO). Ala03- 2S? Oa) and gelenite (2CaO-Ala0:? - S? OM), with the addition of erbium and fluorine to provide laser characteristics that have adequate fluorescence lifetimes. The inventor has produced crystals of erbium doped oxyfluoride inosilicate alum by substituting CaO in the mixture compositions for ZnO, alkaline and alkaline-oxide oxides such as MgO, BaO and Naa0. Such glass compositions that incorporate the benefits of the fluorine content of the invention to suppress concentration extinction of the rare earth ions, must exhibit similar laser properties. The glass compositions of the invention further include the substitution of Al20a in the compositions of the mixture by Ga203. Al ^ Oa can be completely replaced in the composition of the mixture by gallium. The composition of the glass mixture of the invention can include 0 to 25 mole percent Slow Gaa03. The crystal compositions of the invention also include the substitution of O in the compositions of the mixture by GeOa. It can be completely replaced S? Oi in the composition of the mixture by germnamo. The composition of the glass mixture of the invention can include 0 to 50 mole percent of GeOa. The glass composition of the invention also includes the substitution of AlO in the composition of the mixture by EaO3. Aluminum can be substituted in the composition of the mixture by boron. The composition of the glass mixture of the invention can include from 0 to 15 mol percent of a0.

In addition to the modalities discussed above, it will be clear to persons skilled in the art that numerous modifications and changes may be made to the previous invention without departing from its intended spirit and scope.

Claims

NOVFDAIN OF THE INVENTION CLAIMS

1. - A doped oxyhalogenide laser crystal with a plurality of rare earth ions, said cpstal has a fluorescence lifetime of at least about 6 rnsec, characterized in that said crystal has a sufficient halogenide concentration to inhibit extinction of concentration of said rare earth ions.

2. A laser crystal according to claim 1, characterized in that said halide concentration is comprised of at least 6.2% by weight of F.

3. A laser crystal according to claim 1, further characterized in that said rare earth ions are erbium.

4. An oxyhalide laser crystal according to claim 1, characterized in that said oxyhalide laser crystal is an L-crystal of oxyhalide fluoride.

5.- A laser-contaminated glass with rare earth elements, said laser crystal. • Fill a molar mixture of 45 to 70 mole percent of S? Oa; from 15 to 35 moles of X; from 15 to 35 moles per cent of Y; wherein X is a metal oxide selected from the group consisting of alkali metal oxides, alkaline earth metal oxides, and ZnO; and Y is an aluminum compound selected from the group consisting of aluminum oxide and aluminum halide, and at least 10 moles per cent. Slow Y is aluminum halide.

6. A laser crystal according to claim 5, further characterized in that said crystal of L is impurified with erbium.

7. A laser crystal according to claim 5, further characterized in that X is CaO.

8. A laser crystal according to claim 5, further characterized in that said aluminum halide is FFA.

9. A laser crystal according to claim 5, further characterized in that said laser crystal exhibits a fluorescence lifetime of at least 6 milli seconds.

10. A laser crystal having a composition in weight percentage in the mixture of 30 to 45% by weight of LO ^; from 25 to 45% by weight of AlaOa; from 10 to 25% by weight of CaO; from 0.005 to 10% by weight of Er203; and from 7 to 35% by weight of F; and said crystal has an analyzed content of F of at least 6.2% by weight.

11. A laser crystal, according to claim 10, further characterized in that the F is mixed as AiaF6.

12. - A laser crystal - having a composition in percentage by weight in the mixture consisting essentially of 37 to 40% by weight of S? Oa; from 30 to 40% by weight of ñl ^ Oa, - from 0.005 to 5% by weight of EraO; and from 9 to 30% by weight of F; and d?; ho glass has an analyzed content of F of at least 6.5% by weight.

13.- An oxygen dioxide laser crystal doped with a plurality of erbium ions, said erbium ions are contained in a concentration of at least 10 X / cm3, said crystal has an analyzed content of fluorine in percentage of weight of at least 6.2% by weight of fluorine, and said crystal exhibits a fluorescence lifetime of at least 7.6 s.

14. A laser crystal according to claim 13, further characterized in that said rtuo ions are contained in a concentration of at least 1 x [eí jones / crn3.

15. An oxy halide laser crystal having a blend composition consisting of at least 13% by weight of F and at least 2% by weight of EraOa, and said crystal exhibits a fluorescence lifetime of at least 6 ms

16. A laser crystal according to claim 15, further characterized in that said laser crystal has a stoichiometry of the crystalline phase of anorthite or of the crystalline phase of geleruta.

17. - An optical amplifier formed of a laser crystal - having a mixture composition in percentage by weight constituted from 30 to 45% by weight of S Oa; from 25 to 45% by weight of Ala0: -J; from 10 to 25% by weight of CaO; from 0.005 to 10% by weight of FraOa; and from 7 to 35% by weight of F; and said crystal has an analyzed content of F of at least 6.2% by weight.

18. A method of inhibiting the concentration extinction of a rare earth impurifier in a laser crystal, said method comprises the step of replacing an oxygen ion in the laser crystal with a halogen ion. 19.- A crystal of it being impurified with rare earth elements, said laser crystal having a mixing composition consisting essentially of 45 to 70 moles per cent of S? Oa; from 15 to 35 moles of X; from 15 to 35 moles per cent of Y; wherein X is a metal selected from the group consisting of alkali metal oxides, oxides of metal at cal and noterreous, and ZnO; and Y is an aluminum compound selected from the group consisting of aluminum oxide and aluminum halide, and at least 10 mole percent of Y is aluminum halide. 20.- A laser crystal contaminated with rare earth elements, said laser crystal has a molar composition of mixture consisting of 45 to 70 moles of A; from 15 to 35 moles of X; from 15 to 35 moles per cent of Y; wherein A is a compound selected from the group consisting of L? a and GeOa; and X is a metal oxide selected from group 13 consisting of alkali metal oxides, alkaline motor oxides, and ZnO; and Y is a compound selected from the group consisting of aluminum oxide, aluminum halide, 6aa0p, and Ba0a, wherein at least 10 moles of Y is aluminum halide.