A transition metal ion-doped scandium oxide laser crystal and its preparation method

Abstract

The present invention relates to a transition metal ion doped scandium oxide laser crystal and a preparation method thereof. The chemical formula of the laser crystal is (TM x Sc 1‑x )2O3; wherein TM is a transition metal element, 0.0001≤x≤0.03, that is, the laser crystal uses scandium oxide crystal as the matrix crystal, transition metal ions as the activation ions, especially Ti 3+ Cr 3+ or Fe 3+ As an activating ion. This invention overcomes the technical problem that transition metal ions have difficulty forming luminescent centers in traditional oxide-based crystals. A new type of near-infrared laser crystal is prepared. By using scandium oxide with weak crystal field coupling as the matrix of the transition metal ion-doped laser crystal, the effective incorporation of transition metal ions into the scandium oxide matrix can reach more than one thousandth.

Description

Technical Field

[0001] The present invention relates to the field of laser crystal materials and all-solid-state laser technology, and in particular to a transition metal ion-doped scandium oxide laser crystal and a preparation method thereof. Background Art

[0002] Transition Metal (TM) ion-doped laser materials have a long history of research and development. In fact, the first laser output achieved by humans was from the transition metal ion Cr 3+ Doped sapphire crystal (commonly known as ruby). Near-infrared lasers have attracted widespread attention due to their important new applications in optical communications, gas detection, biomedicine, directional infrared countermeasures and other fields, and have become a new frontier in the development of laser crystals. Among them, Cr 3+ Ions have 3d 3 When the shell structure is used as the active ion of the tunable laser crystal, the weak crystal field coupling condition of trivalent Cr ion is usually used. 2 E→ 4 The transition between A2, this transition will vary greatly with the change of crystal field intensity, and has the advantages of large Huang Kun-Reese factor, wider spectral line width, wide tunable range, covering the entire infrared band, large absorption and emission cross-section, and can achieve high quantum efficiency and low excited state absorption at room temperature. However, it is difficult for TM ions to form luminescence centers in traditional oxide matrices, and it is very easy to form concentration quenching and macro defects. The effective doping amount is usually only one thousandth of the order, and the proportion of luminescence centers formed is even rarer. Due to the limitations of the test level, it is impossible to directly test the number and concentration of luminescence centers, and it can only be inferred through comparison of spectral data. Insufficient luminescence centers result in insufficient absorption of the lower energy level, and an insufficient number of inversion particles cannot be formed. Insufficient effective doping amount makes it impossible to cause sufficiently strong crystal field distortion, which hinders Ti 3 + Cr 3+ Therefore, finding a matrix material that can achieve weak crystal field coupling conditions is of great significance for improving near-infrared lasers using transition metal ions as gain media. Summary of the Invention

[0003] In view of the problems existing in the prior art, the present invention provides a transition metal ion doped scandium oxide laser crystal and a preparation method thereof. The chemical formula of the laser crystal is (TM x Sc 1-x )2O3; wherein TM is a transition metal element, 0.0001≤x≤0.03, that is, the laser crystal uses scandium oxide as the matrix crystal, and transition metal ions as the activation ions, especially Cr 3+、Ti 3+ or Fe 3+ As an activating ion. This invention overcomes the technical problem that transition metal ions have difficulty forming luminescent centers in traditional oxide-based crystals. A new type of near-infrared laser crystal is prepared. By using scandium oxide with weak crystal field coupling as the matrix of the transition metal ion-doped laser crystal, the effective incorporation of transition metal ions into the scandium oxide matrix can reach more than one thousandth.

[0004] To achieve this object, the present invention adopts the following technical solutions:

[0005] One of the purposes of the present invention is to provide a transition metal ion doped scandium oxide laser crystal, wherein the chemical formula of the transition metal ion doped scandium oxide laser crystal is (TM x Sc 1-x )2O3; wherein TM is a transition metal element, 0.0001≤x≤0.03.

[0006] The present invention overcomes the technical problem that transition metal ions are difficult to form luminescent centers in traditional oxide matrix crystals, and prepares a new type of laser crystal. By using scandium oxide with weak crystal field coupling as the matrix of the transition metal ion-doped laser crystal, the effective incorporation amount of transition metal ions in the scandium oxide matrix can reach more than one thousandth.

[0007] The chemical formula of the transition metal ion doped scandium oxide laser crystal of the present invention is (TM x Sc 1-x )2O3, wherein 0.0001≤x≤0.03, x can be 0.0001, 0.0005, 0.001, 0.005, 0.008, 0.01, 0.015, 0.02, 0.025 or 0.03, etc., but is not limited to the listed values, and other values not listed within the above numerical range are also applicable.

[0008] It is worth noting that the chemical formula of the transition metal ion doped scandium oxide laser crystal of the present invention is (TM x Sc 1-x )2O3, wherein 0.0001≤x≤0.03, means that the atomic percentage of TM as the active ion in the cations in the laser crystal is 0.01-3at%.

[0009] As a preferred technical solution of the present invention, the TM is any one of Ti, Cr or Fe.

[0010] As a preferred technical solution of the present invention, it is characterized in that the chemical formula of the transition metal ion-doped scandium oxide laser crystal is (TM x Sc 1-x)2O3; wherein TM is a transition metal element, 0.001≤x≤0.03.

[0011] A second object of the present invention is to provide a method for preparing the transition metal ion-doped scandium oxide laser crystal described in the first object, the method comprising the following steps:

[0012] (1) According to the chemical formula (TM x Sc 1-x )2O3 chemical dosage ratio, weighing Sc2O3 powder and TM2O3 powder and mixing; wherein TM is a transition metal element, 0.0001≤x≤0.03;

[0013] (2) subjecting the mixed powder obtained in step (1) to pressing and sintering in sequence to obtain a blank;

[0014] (3) The blank obtained in step (2) is melted, and a single crystal is formed and grown by a descending method to obtain a transition metal ion-doped scandium oxide laser crystal.

[0015] It is worth noting that scandium oxide is extremely difficult to grow using the pulling method and guided mold method. It is usually grown using the descent method or heat exchange method. However, the heat exchange method is more expensive. The present invention gives priority to the descent method and does not exclude the use of the heat exchange method.

[0016] As a preferred technical solution of the present invention, the TM2O3 powder in step (1) is any one of Ti2O3 powder, Cr2O3 powder or Fe2O3 powder.

[0017] Preferably, the purity of the Sc2O3 powder in step (1) is ≥99%.

[0018] Preferably, the purity of the TM2O3 powder in step (1) is ≥99%.

[0019] Preferably, the mixing in step (1) is carried out in a mixer.

[0020] As a preferred technical solution of the present invention, the pressing treatment in step (2) is carried out in a hydraulic press.

[0021] Preferably, the pressure of the pressing treatment in step (2) is 200-250 MPa, for example, 200 MPa, 205 MPa, 210 MPa, 215 MPa, 220 MPa, 225 MPa, 230 MPa, 235 MPa, 240 MPa, 245 MPa or 250 MPa, etc., but is not limited to the listed values. Other values not listed within the above numerical range are also applicable.

[0022] Preferably, the pressing treatment time in step (2) is 5-10 min, for example, 5 min, 5.5 min, 6 min, 6.5 min, 7 min, 7.5 min, 8 min, 8.5 min, 9 min, 9.5 min or 10 min, etc., but is not limited to the listed values, and other values not listed within the above numerical range are also applicable.

[0023] As a preferred technical solution of the present invention, the sintering treatment in step (2) is carried out in a muffle furnace.

[0024] Preferably, the temperature of the sintering treatment in step (2) is 1300-1800°C, for example, 1300°C, 1350°C, 1400°C, 1450°C, 1500°C, 1550°C, 1600°C, 1650°C, 1700°C, 1750°C or 1800°C, etc., but is not limited to the listed values, and other values not listed within the above numerical range are also applicable.

[0025] Preferably, the sintering treatment time in step (2) is 10-15h, for example, 10h, 10.5h, 11h, 11.5h, 12h, 12.5h, 13h, 13.5h, 14h, 14.5h or 15h, etc., but is not limited to the listed values, and other values not listed within the above numerical range are also applicable.

[0026] Preferably, the sintering treatment in step (2) is carried out in an air atmosphere.

[0027] As a preferred technical solution of the present invention, in step (3), the blank obtained in step (2) is placed in a rhenium crucible for melting treatment.

[0028] Preferably, the temperature of the melting treatment in step (3) is 2500-3000°C, for example, 2500°C, 2550°C, 2600°C, 2650°C, 2700°C, 2750°C, 2800°C, 2850°C, 2900°C, 2950°C or 3000°C, etc., but is not limited to the listed values, and other values not listed within the above numerical range are also applicable.

[0029] It is worth noting that the temperature of the melting treatment described in the present invention is 2500-3000°C, which can not only achieve the gradual melting of the scandium oxide matrix crystal, but also far exceed the melting point of the transition metal ions serving as activating ions, thereby forming a certain transition metal ion vapor pressure in the high-temperature resistant rhenium crucible, thereby facilitating the subsequent descent method to form a single crystal and grow a transition metal ion-doped scandium oxide laser crystal.

[0030] Preferably, the protective gas for the melting treatment in step (3) is a mixed gas of hydrogen and oxygen.

[0031] Preferably, the oxygen partial pressure ratio in the mixed gas is 0.01-3%, for example, 0.01%, 0.05%, 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5% or 3%, etc., but is not limited to the listed values. Other values not listed within the above numerical range are also applicable.

[0032] As a preferred technical solution of the present invention, the laser crystal grown in step (3) is annealed to obtain a transition metal ion-doped scandium oxide laser crystal.

[0033] Preferably, the annealing temperature is 1300-1600°C, such as 1300°C, 1350°C, 1400°C, 1450°C, 1500°C, 1550°C or 1600°C, but is not limited to the listed values. Other values not listed within the above range are also applicable.

[0034] It is worth noting that the preparation method of the present invention includes annealing treatment and controlling the temperature to 1300-1600°C, which can avoid the occurrence of problems such as a large amount of internal stress and defects formed during the growth process of the scandium oxide matrix crystal due to its high melting point, thereby obtaining a transparent scandium oxide matrix crystal.

[0035] As a preferred technical solution of the present invention, the preparation method comprises the following steps:

[0036] (1) According to the chemical formula (TM x Sc 1-x )2O3 chemical dosage ratio, weighing Sc2O3 powder with a purity of ≥99% and TM2O3 powder with a purity of ≥99% and mixing them in a mixer;

[0037] Wherein, TM is a transition metal element, 0.0001≤x≤0.03; the TM2O3 powder is any one of Ti2O3 powder, Cr2O3 powder or Fe2O3 powder;

[0038] (2) placing the mixed powder obtained in step (1) into a hydraulic press, pressing at 200-250 MPa for 5-10 min, then placing the obtained block mixture into a muffle furnace, and sintering at 1300-1800° C. in an air atmosphere for 10-15 h to obtain a blank;

[0039] (3) placing the blank obtained in step (2) into a rhenium crucible, heating it to 2500-3000° C. for melting treatment, wherein the protective gas for the melting treatment is a mixture of hydrogen and oxygen, and the oxygen partial pressure ratio in the mixture is controlled to be 0.01-3%, forming a single crystal and growing it by a descending method, and annealing the produced laser crystal at 1300-1600° C. to obtain a transition metal ion-doped scandium oxide laser crystal.

[0040] It is worth noting that, in the preparation method of the present invention, after the mixed raw materials are fully melted, a temperature gradient is formed by descending the crucible, and then the melt forms a single crystal and grows under the action of a seed crystal or by spontaneous nucleation, and then grows upward as the crucible descends to obtain an inch-scale transition metal ion-doped scandium oxide laser crystal; In addition, the preparation method of the present invention is according to the chemical formula (TM x Sc 1-x )2O3 (0.0001≤x≤0.03) to weigh Sc2O3 powder and TM2O3 powder, which can avoid excessively high proportion of transition ions in the melt obtained by melting, resulting in serious devitrification or external cracking of the laser crystal as a whole.

[0041] Compared with the existing technical solutions, the present invention has at least the following beneficial effects:

[0042] The present invention overcomes the technical problem that transition metal ions are difficult to form luminescence centers in traditional oxide matrix crystals, and prepares a new type of near-infrared laser crystal. By using scandium oxide with weak crystal field coupling as the matrix of the transition metal ion-doped laser crystal, the effective incorporation amount of transition metal ions in the scandium oxide matrix can reach more than one thousandth. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 1 is a comparison diagram of the visible band absorption spectra and the corresponding energy level transitions of the transition metal ion-doped scandium oxide laser crystals obtained in Example 1 and Example 2;

[0044] Figure 2 This is a comparison of the fluorescence spectra of the transition metal ion-doped scandium oxide laser crystals obtained in Example 1 and Example 2 under excitation by an Ar lamp at 488 nm;

[0045] Figure 3 This is a graph showing the fluorescence lifetime of the transition metal ion-doped scandium oxide laser crystal obtained in Example 1, corresponding to the emission at 799 nm under 488 nm excitation by an Ar lamp;

[0046] Figure 4 This is a curve chart of the fluorescence lifetime of the transition metal ion-doped scandium oxide laser crystal obtained in Example 2, corresponding to the emission at 799 nm under 488 nm excitation of an Ar lamp. DETAILED DESCRIPTION

[0047] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific implementation methods.

[0048] To better illustrate the present invention and facilitate understanding of the technical solutions of the present invention, typical but non-limiting embodiments of the present invention are as follows:

[0049] Example 1

[0050] This embodiment provides a method for preparing a transition metal ion-doped scandium oxide laser crystal, the method comprising the following steps:

[0051] (1) According to the chemical formula (Cr 0.005 Sc 0.995 )2O3 chemical dosage ratio, weigh 99% pure Sc2O3 powder and 99% pure Cr2O3 powder and mix them in a mixer;

[0052] (2) placing the mixed powder obtained in step (1) into a hydraulic press and pressing at 210 MPa for 5 min, then placing the obtained block mixture into a muffle furnace and sintering it at 1500° C. for 12 h in an air atmosphere to obtain a blank;

[0053] (3) placing the blank obtained in step (2) into a rhenium crucible, heating it to 2500° C. for melting treatment, wherein the protective gas for the melting treatment is a mixture of hydrogen and oxygen, and the oxygen partial pressure ratio in the mixture is controlled to be 0.1%, forming a single crystal and growing it by a descending method, and annealing the produced laser crystal at 1500° C. to obtain a transition metal ion-doped scandium oxide laser crystal.

[0054] Example 2

[0055] This embodiment provides a method for preparing a transition metal ion-doped scandium oxide laser crystal, which is based on the preparation method described in Example 1, with the only difference being that: in step (1), the chemical formula (TM x Sc 1-x )2O3 corresponds to x = 0.01; the specific content is as follows:

[0056] (1) According to the chemical formula (Cr 0.01 Sc 0.99 )2O3 chemical dosage ratio, weigh 99% pure Sc2O3 powder and 99% pure Cr2O3 powder and mix them in a mixer.

[0057] Example 3

[0058] This embodiment provides a method for preparing a transition metal ion-doped scandium oxide laser crystal, which is based on the preparation method described in Example 1, with the only difference being that: in step (1), the chemical formula (TM x Sc 1-x )2O3 corresponds to x = 0.03; the specific content is as follows:

[0059] (1) According to the chemical formula (Cr 0.03 Sc 0.97)2O3 chemical dosage ratio, weigh Sc2O3 powder with a purity of 99.999% and Cr2O3 powder with a purity of 99.999% and mix them in a mixer.

[0060] Example 4

[0061] This embodiment provides a method for preparing a transition metal ion-doped scandium oxide laser crystal, which is based on the preparation method described in Example 1, with the only difference being that: in step (1), the chemical formula (TM x Sc 1-x )2O3 corresponds to x = 0.0001; the specific content is as follows:

[0062] (1) According to the chemical formula (Cr 0.0001 Sc 0.9999 )2O3 chemical dosage ratio, weigh Sc2O3 powder with a purity of 99.999% and Cr2O3 powder with a purity of 99.999% and mix them in a mixer.

[0063] Example 5

[0064] This embodiment provides a method for preparing a transition metal ion-doped scandium oxide laser crystal. The method is based on the preparation method described in Example 2, with the only difference being that the Cr2O3 powder in step (1) is replaced with Ti2O3 powder. The specific details are as follows:

[0065] (1) According to the chemical formula (Ti 0.01 Sc 0.99 )2O3 chemical dosage ratio, weigh 99% pure Sc2O3 powder and 99% pure Ti2O3 powder and mix them in a mixer.

[0066] Example 6

[0067] This embodiment provides a method for preparing a transition metal ion-doped scandium oxide laser crystal. The method is based on the preparation method described in Example 2, with the only difference being that the Cr2O3 powder in step (1) is replaced with Fe2O3 powder. The specific contents are as follows:

[0068] (1) According to the chemical formula (Fe 0.01 Sc 0.99 )2O3 chemical dosage ratio, weigh 99% pure Sc2O3 powder and 99% pure Fe2O3 powder and mix them in a mixer.

[0069] Taking the transition metal ion-doped scandium oxide laser crystals obtained in Examples 1 and 2 of the present invention as an example, the visible band absorption spectra were respectively obtained and the absorption cross sections of the corresponding energy level transitions were calculated. The comparison diagram of the obtained visible band absorption spectra and the corresponding energy level transitions is shown in FIG. Figure 1As shown; the fluorescence spectra of the wavelength range from 798 nm to 488 nm under the excitation of Ar lamp were respectively obtained, and the comparison of the fluorescence spectra under the excitation of Ar lamp at 488 nm was shown in FIG. Figure 2 As shown; the fluorescence lifetime test of ~799nm luminescence under 488nm excitation of Ar lamp was carried out respectively, and the comparison chart obtained is shown in Figure 3 and Figure 4 Based on the above test results, the luminescence cross-section data in the ~798nm band were calculated. The above test results are summarized in Table 1; similarly, the corresponding results of the transition metal ion-doped scandium oxide laser crystals obtained in Examples 3-6 are also at an excellent level.

[0070] Table 1

[0071]

[0072] With the Cr 3+ The ion doping concentration increases from 0.5% to 1%, at 488nm 4 A2→ 4 T1 absorption cross section increased from 0.37 cm -1 Rising to 0.5cm -1 , at 798nm 2 E→ 4 The fluorescence of A2 under the same test conditions was 0.7×10 5 Significantly increased to 2.6×10 5 , the emission cross section is 1.24×10 -22 cm 2 Increased to 1.32×10 -22 cm 2 The luminescence performance parameters are all enhanced, indicating that the saturation state has not been reached. The fluorescence lifetime remains unchanged, indicating that no new luminescence centers are generated. The gains in absorption cross section, luminescence intensity and emission cross section all come from the increase in the concentration of luminescence centers. Similarly, in Fe 3+ and Ti 3+ In scandium oxide-doped crystals, spectral parameters such as absorption cross section and emission cross section achieve similar gain effects.

[0073] In summary, the present invention overcomes the technical problem that transition metal ions are difficult to form luminescence centers in traditional oxide matrix crystals, and prepares a new type of near-infrared laser crystal. By using weak crystal field coupled scandium oxide as the matrix of the transition metal ion-doped laser crystal, the effective incorporation amount of transition metal ions in the scandium oxide matrix can reach more than one thousandth.

[0074] While the present invention is described through the above-described embodiments to illustrate the detailed structural features of the present invention, the present invention is not limited to these detailed structural features, nor does it necessarily rely on these detailed structural features for implementation. Those skilled in the art should understand that any improvements to the present invention, equivalent replacements for selected components, additions of auxiliary components, and selection of specific embodiments, etc., fall within the scope of protection and disclosure of the present invention.

[0075] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0076] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0077] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for preparing a transition metal ion-doped scandium oxide laser crystal, characterized in that: The preparation method comprises the following steps: (1) According to the chemical formula (TM x Sc 1-x )2O3 chemical dosage ratio, weighing Sc2O3 powder and TM2O3 powder and mixing; wherein TM is Cr, 0.005≤x≤0.01; (2) subjecting the mixed powder obtained in step (1) to pressing and sintering in sequence to obtain a blank; (3) melting the blank obtained in step (2), forming a single crystal and growing it by a descending method to obtain a transition metal ion-doped scandium oxide laser crystal; The temperature of the melting treatment in step (3) is 2500-3000°C; The protective gas for the melting treatment in step (3) is a mixed gas of hydrogen and oxygen; The chemical formula of the transition metal ion doped scandium oxide laser crystal is (TM x Sc 1-x )2O3; wherein TM is Cr, 0.005≤x≤0.

01.

2. The preparation method according to claim 1, characterized in that The TM2O3 powder in step (1) is Cr2O3 powder.

3. The preparation method according to claim 1, characterized in that The purity of the Sc2O3 powder in step (1) is ≥99%.

4. The preparation method according to claim 1, characterized in that The purity of the TM2O3 powder in step (1) is ≥99%.

5. The preparation method according to claim 1, characterized in that The mixing in step (1) is carried out in a mixer.

6. The preparation method according to claim 1, characterized in that The pressing process in step (2) is carried out in an oil press.

7. The preparation method according to claim 1, characterized in that The pressure of the pressing treatment in step (2) is 200-250 MPa.

8. The preparation method according to claim 1, characterized in that The pressing time in step (2) is 5-10 minutes.

9. The preparation method according to claim 1, characterized in that The sintering treatment in step (2) is carried out in a muffle furnace.

10. The preparation method according to claim 1, characterized in that The temperature of the sintering treatment in step (2) is 1300-1800°C.

11. The preparation method according to claim 1, characterized in that The sintering treatment time in step (2) is 10-15 hours.

12. The preparation method according to claim 1, characterized in that The sintering treatment in step (2) is carried out in an air atmosphere.

13. The preparation method according to claim 1, characterized in that In step (3), the blank obtained in step (3) is placed in a rhenium crucible for melting treatment.

14. The preparation method according to claim 1, characterized in that The oxygen partial pressure ratio in the mixed gas is 0.01-3%.

15. The preparation method according to claim 1, characterized in that The laser crystal grown in step (3) is annealed to obtain a transition metal ion-doped scandium oxide laser crystal.

16. The preparation method according to claim 15, characterized in that The temperature of the annealing treatment is 1300-1600°C.

17. The preparation method according to claim 1, characterized in that The preparation method comprises the following steps: (1) According to the chemical formula (TM x Sc 1-x )2O3 chemical dosage ratio, weighing Sc2O3 powder with a purity of ≥99% and TM2O3 powder with a purity of ≥99% and mixing them in a mixer; Wherein, TM is Cr, 0.005≤x≤0.01; the TM2O3 powder is Cr2O3 powder; (2) placing the mixed powder obtained in step (1) into a hydraulic press, pressing at 200-250 MPa for 5-10 min, then placing the obtained block mixture into a muffle furnace, and sintering at 1300-1800° C. in an air atmosphere for 10-15 h to obtain a blank; (3) placing the blank obtained in step (2) into a rhenium crucible, heating it to 2500-3000° C. for melting treatment, wherein the protective gas for the melting treatment is a mixture of hydrogen and oxygen, and the oxygen partial pressure ratio in the mixture is controlled to be 0.01-3%, forming a single crystal and growing it by a descending method, and annealing the produced laser crystal at 1300-1600° C. to obtain a transition metal ion-doped scandium oxide laser crystal.

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