Dysprosium ion-activated orthophosphate mixed crystal and its yellow-light band solid-state laser

Abstract

The present invention discloses a class of dysprosium ion-activated orthophosphate mixed crystals, belonging to the field of solid laser materials and devices. The molecular formula of this class of crystal materials is: Lu 1‑2x‑y Y y Bi x Dy x PO4, where: 0 < x ≤ 0.1, 0 < y < 0.8. In the present invention, Dy 3+ ions are doped into the orthophosphate mixed crystal, and Y 3+ ions with similar radii are introduced to enhance the absorption of the pump light by the crystal, and Bi 3+ ions with larger radii are introduced to enhance the yellow light emission. The dysprosium ion-activated orthophosphate mixed crystal laser crystal is prepared by the molten salt method. Using this crystal as the gain medium and pumping with a semiconductor laser with a wavelength near 450 nm, high-performance yellow light band solid laser output in the 565-590 nm band can be realized.

Description

Technical Field

[0001] The invention relates to the field of solid laser materials and devices, and in particular to a dysprosium ion activated orthophosphate mixed crystal laser crystal. Technical Background

[0002] Solid-state lasers in the yellow wavelength band have important application value in the fields of measurement, display, military, biomedicine and storage. Dysprosium ions have a rich energy level structure. 4 F 9 / 2 → 6 H 13 / 2 The transition can achieve yellow laser emission in the band around 575nm. 3+ The absorption of ions near 450nm of pump light and the emission of yellow light are both weak, making it difficult to realize Dy 3+ There are relatively few types of crystals that can activate visible-band solid-state lasers. The only crystal that has been publicly reported is Dy 3+ :KGd(WO4)2、Dy 3+ :KY(WO4)2、Dy 3+ :YAG、Dy 3+ :Tb 3+ :LiLuF4 and Dy 3+ :ZnWO4, and the output power is relatively low.

[0003] LuPO4 crystals are a class of excellent matrix crystal materials with stable physical and chemical properties and a high melting point. However, directly using dysprosium ions to activate LuPO4 crystals as gain media cannot achieve laser output.

[0004] In summary, in the prior art, Dy 3+ The performance of ion-activated yellow laser crystals cannot meet the needs of practical applications. Summary of the invention

[0005] The present invention aims to provide a dysprosium ion activated orthophosphoric acid mixed crystal laser crystal Lu 1-2x-y Y y Bi x Dy x PO4, of which: 0 <x≤0.1,0<y<0.8,通过在正磷酸盐LuPO4晶体中引入半径相近的Y 3+ Ion increases Dy 3+ The half-width of the absorption peak of ions in the crystal enhances the absorption of pump light by the crystal and introduces Bi with a larger radius. 3+ ions, which can improve Dy without changing the crystal structure 3+ The ion coordination environment enhances the yellow light emission, thereby enhancing the absorption of pump light and the yellow light emission of the dysprosium ion-activated yellow light band laser crystal, thereby achieving the output of yellow light band laser.

[0006] Further, the crystal belongs to the tetragonal crystal system and the space group is I41.

[0007] Further, x can be 0.01, 0.02, 0.03, etc., and y can be 0.4, 0.5, 0.6, etc. The orthophosphoric acid mixed crystal laser crystal is Lu 0.28 Y 0.7 Bi 0.01 Dy 0.01 PO4, Lu 0.36 Y 0.6 Bi 0.02 Dy 0.02 PO4, Lu 0.48 Y 0.5 Bi 0.01 Dy 0.01 PO4, Lu 0.56 Y 0.4 Bi 0.02 Dy 0.02 PO4, etc. All of the above crystals belong to the tetragonal crystal system and the space group is I41.

[0008] Further, the dysprosium ion-activated orthophosphate mixed crystal is prepared by a molten salt method.

[0009] Further, for the use of the dysprosium ion-activated orthophosphate mixed crystal, the crystal is used as a gain medium of a laser.

[0010] Further, the present invention also provides a solid laser in the 565 - 590 nm band, which is composed of a semiconductor laser pumping system, a laser resonator and a gain medium. The aforementioned crystal is used as the gain medium of the laser; the semiconductor laser pumping system includes a light source with an emission wavelength near 450 nm and an optical coupler placed between the light source and the resonator; the laser resonator is composed of an input mirror and an output mirror; the input mirror is designed to have a transmittance T≥80% near the wavelength of 450 nm and a transmittance T≤0.5% in the 565 - 590 nm band; the output mirror is designed to have a transmittance of 0.5%≤T≤10% in the 565 - 590 nm band.

[0011] Further, the input mirror and the output mirror are respectively directly coated on one or two opposite end faces of the gain medium.

[0012] Further, using such a crystal as the gain medium, a yellow solid laser output in the 565 - 590 nm band is obtained.

[0013] The beneficial effects of the present invention are as follows:

[0014] (1) By introducing Y with a similar radius into the orthophosphate LuPO4 crystal 3+Ions can increase the full width at half maximum of the absorption peak of Dy ions in the crystal while ensuring the structural stability, and enhance the absorption of the pump light by the crystal. 3+

[0015] (2) Introduce Bi ions with the same amount as the activator ions but a larger radius into the crystal, which can improve the coordination environment of Dy ions without changing the crystal structure and enhance the yellow light emission. Finally, high-performance yellow light band laser output is achieved through this crystal. 3+ 3+

[0016] (3) The present invention prepares for the first time the LuYBiDyPO4 laser crystal. Data shows that this crystal material can be used as a new laser crystal material for realizing yellow light laser output in the range of 565 - 590 nm. 1-2x-y Y y Bi x Dy x Description of the Drawings

[0017] Figure 1 : XRD pattern of the laser crystal prepared in Example 1.

[0018] Figure 2 : Emission spectrum of the sample prepared in Example 1. Detailed Embodiments

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0020] Preparation Example 1: Grow the LuYBiDyPO4 laser crystal by the molten salt method. Charge the raw materials Lu2O3 (4N), Y2O3 (4N), Dy2O3 (5N), Bi2O3 and the flux PbHPO4 according to the molar ratio of the chemical formula LuYBiDyPO4; then fully mix them into a uniform mixed powder, press it into a cylindrical block under a pressure of 1 - 4 GPa, put the block into a platinum crucible, place it in a molten salt furnace, grow the crystal at a temperature of 1000 - 1250 °C, then cool down and anneal to take out the crystal; after pickling, obtain the LuYBi 0.56 Y 0.4 Bi 0.02 Dy 0.02 0.56 Y 0.4 Bi 0.02 Dy 0.02 0.56 Y 0.4 Bi0.02 Dy 0.02 PO4 transparent crystal. Figure 1 and Figure 2 are the XRD spectrogram and emission spectrogram of the sample obtained by testing respectively. The results show that Y 3+ , Bi 3+ and Dy 3+ addition does not cause the change of crystal structure; the sample has strong absorption near 450nm band and strong emission in yellow light band.

[0021] Comparative Example 1: Using the molten salt method to grow Lu 3+ and Bi 3+ ion-free 0.98 Dy 0.02 PO4 laser crystal. The specific crystal growth process is as in Example 1, and the test data of the absorption / emission full width at half maximum, peak absorption cross section and peak emission cross section of the crystal are shown in Table 1. The experimental results show that the absorption and emission performance parameters of the Lu 3+ and Bi 3+ ion-free crystal are lower than the corresponding parameters of other crystals, as shown in Table 1 specifically.

[0022] Comparative Example 2: Using the molten salt method to grow Lu 3+ ion-free 0.96 Bi 0.02 Dy 0.02 PO4 laser crystal. The specific crystal growth process is as in Example 1, and the test data of the absorption / emission full width at half maximum, peak absorption cross section and peak emission cross section of the crystal are shown in Table 1. The experimental results show that after doping with Bi 3+ , the peak emission cross section increases from 5.0×10 -22 cm 2 to 5.7×10 -22 cm 2 ; doping with Bi 3 + can greatly increase the peak emission cross section, that is, enhance the yellow light emission of the crystal.

[0023] Comparative Example 3: Using the molten salt method to grow Lu 3+ ion-free 0.58 Y 0.4 Dy 0.02 PO4 laser crystal. The specific crystal growth process is as in Example 1, and the test data of the absorption / emission full width at half maximum, peak absorption cross section and peak emission cross section of the crystal are shown in Table 1. The experimental results show that after doping with Y 3+ , the full width at half maximum of the absorption peak increases from 6.3nm to 8.5nm, and the increase of the half-width can effectively increase the absorption of the pump light by the laser crystal.

[0024] It can be seen by comparing Example 1 with Comparative Examples 2 and 3 that when Bi 3+ and Y 3+ are doped simultaneously, compared with the effect of doping Bi 3+ and Y 3+ separately, this result indicates that doping Bi 0.98 and Y 0.02 in Lu 3+ Dy 3+ PO4 crystals has a certain synergistic effect on achieving yellow light band emission, and stable yellow light laser output can be obtained by simultaneous doping.

[0025] Table 1. Absorption / Emission Full Width at Half Maximum, Peak Absorption Cross Section and Peak Emission Cross Section of Different Crystals

[0026]

[0027] Preparation Example 2: Growing Lu 0.68 Y 0.3 Bi 0.01 Dy 0.01 PO4 laser crystal. Mix the raw materials Lu2O3 (4N), Y2O3 (4N), Dy2O3 (5N), Bi2O3 and the flux PbHPO4 according to the molar ratio of the chemical formula Lu 0.68 Y 0.3 Bi 0.01 Dy 0.01 PO4; then mix them thoroughly into a uniform mixed powder, press it into a cylindrical block under a pressure of 1 - 4 GPa, put the block into a platinum crucible, place it in a molten salt furnace, grow the crystal at a temperature of 1000 - 1250 °C, then cool down, anneal and take out the crystal; after pickling, obtain Lu 0.68 Y 0.3 Bi 0.01 Dy 0.01 PO4 transparent crystal. The test results show that the addition of Y 3+ , Bi 3+ and Dy 3+ does not cause a change in the crystal structure; the sample has strong absorption near the 450 nm band and strong emission in the yellow light band.

[0028] Preparation Example 3: Growing Lu 0.46 Y 0.5 Bi 0.02 Dy 0.02 PO4 laser crystal. Mix the raw materials Lu2O3 (4N), Y2O3 (4N), Dy2O3 (5N), Bi2O3 and the flux PbHPO4 according to the molar ratio of the chemical formula Lu 0.46 Y 0.5 Bi 0.02 Dy0.02 Mix ingredients according to the molar ratio of PO4; then fully mix them into a uniform mixed powder, press it into a cylindrical block under a pressure of 1-4 GPa, put the block into a platinum crucible, place it in a molten salt furnace, grow crystals at a temperature of 1000-1250 °C, then cool down, anneal and take out the crystals; after pickling, obtain Lu 0.46 Y 0.5 Bi 0.02 Dy 0.02 PO4 transparent crystal. The test results show that the addition of Y 3+ , Bi 3+ and Dy 3+ does not cause a change in the crystal structure; the sample has strong absorption near the 450 nm band and strong emission in the yellow light band.

[0029] Application Example 1: 450 nm semiconductor laser end-pumped Lu 0.52 Y 0.4 Bi 0.04 Dy 0.04 PO4 crystal realizes 570 nm solid laser output.

[0030] Use the molten salt method to grow Lu 0.52 Y 0.4 Bi 0.04 Dy 0.04 PO4 laser crystal, select PbHPO4 as the flux. This crystal belongs to the tetragonal system and is a uniaxial crystal. After orientation with a polarizing microscope, take a section with the light-transmitting surface perpendicular to the c-axis, cut a crystal sample with a thickness of 11 mm (the end area is generally from square millimeters to square centimeters), polish the end faces and place it in the laser cavity. The transmittance T of the input mirror of the laser cavity is 95% at a wavelength of 450 nm and 0.1% at a wavelength of 570 nm; the transmittance T of the output mirror of the laser cavity is 2.0% at a wavelength of 570 nm. Using a 450 nm semiconductor laser end-pumping can achieve continuous 570 nm solid laser output. It is also possible to directly coat the input and output mirrors of the laser cavity on the two end faces of the laser crystal respectively to achieve the same purpose.

[0031] Application Example 2: 450 nm semiconductor laser end-pumped Lu 0.51 Y 0.45 Bi 0.02 Dy 0.02 PO4 crystal realizes 585 nm solid laser output.

[0032] Use the molten salt method to grow Lu 0.51 Y 0.45 Bi 0.02 Dy 0.02For the PO4 laser crystal, PbHPO4 is selected as the flux. This crystal belongs to the tetragonal system and is a uniaxial crystal. After orientation using a polarizing microscope, a slice with the optical transmission plane parallel to the c-axis is taken, and a crystal sample with a thickness of 10 mm (the end area is generally from square millimeters to square centimeters) is cut. After polishing the end faces, it is placed in the laser cavity. The input mirror of the laser cavity has a transmittance T = 90% at a wavelength of 450 nm and a transmittance T = 0.1% at a wavelength of 585 nm; the output mirror of the laser cavity has a transmittance T = 2.0% at a wavelength of 585 nm and a transmittance T > 5% in the wavelength band of 570 - 580 nm. Continuous solid-state laser output at 585 nm can be achieved by end-pumping with a semiconductor laser at a wavelength of 450 nm. It is also possible to directly coat the input and output mirrors of the laser cavity on the two end faces of the laser crystal respectively to achieve the same purpose.

[0033] Application Example 3: End-pumping Lu 0.52 Y 0.4 Bi 0.04 Dy 0.04 PO4 crystal to achieve 570 nm solid-state laser output.

[0034] Using the molten salt method to grow Lu 0.52 Y 0.4 Bi 0.04 Dy 0.04 PO4 laser crystal, PbHPO4 is selected as the flux. This crystal belongs to the tetragonal system and is a uniaxial crystal. After orientation using a polarizing microscope, a slice with the optical transmission plane perpendicular to the c-axis is taken, and a crystal sample with a thickness of 11 mm (the end area is generally from square millimeters to square centimeters) is cut. After polishing the end faces, it is placed in the laser cavity. The input mirror of the laser cavity has a transmittance T = 95% at a wavelength of 450 nm and a transmittance T = 0.1% at a wavelength of 570 nm; the output mirror of the laser cavity has a transmittance T = 2.0% at a wavelength of 570 nm. Continuous solid-state laser output at 570 nm can be achieved by end-pumping with a 450 nm semiconductor laser. It is also possible to directly coat the input and output mirrors of the laser cavity on the two end faces of the laser crystal respectively to achieve the same purpose.

[0035] Application Example 4: End-pumping Lu 0.3 Y 0.62 Bi 0.04 Dy 0.04 PO4 crystal to achieve 572 nm solid-state laser output.

[0036] Using the molten salt method to grow Lu 0.3 Y 0.62 Bi 0.04 Dy 0.04For the PO4 laser crystal, PbHPO4 is selected as the flux. This crystal belongs to the tetragonal system and is a uniaxial crystal. After orientation using a polarizing microscope, a slice with the optical transmission plane parallel to the c-axis is taken, and a crystal sample with a cutting thickness of 8 mm (the end area is generally from square millimeters to square centimeters) is cut. After the end faces are polished, it is placed in the laser cavity. The transmissivity T of the input mirror of the laser cavity is 85% at a wavelength of 450 nm and 0.3% at a wavelength of 572 nm; the transmissivity T of the output mirror of the laser cavity is 2.5% at a wavelength of 572 nm. Continuous solid laser output at 572 nm can be achieved by end-pumping with a 450 nm semiconductor laser. It is also possible to directly coat the input and output mirrors of the laser cavity on the two end faces of the laser crystal respectively to achieve the same purpose.

[0037] Although the embodiments of the present invention have been disclosed as above, it is not limited to the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the field, additional modifications can be easily made. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to specific details.

Claims

1. A dysprosium ion-activated orthophosphate mixed crystal laser crystal, characterized in that, The molecular formula of the laser crystal is Lu 1-2x-y Y y Bi x Dy x PO4, where: 0.01 ≤ x ≤ 0.1, 0 < y < 0.8; the laser crystal belongs to the tetragonal system, and the space group is I41.

2. The preparation method of the dysprosium ion-activated orthophosphate mixed crystal laser crystal according to claim 1, characterized in that, The laser crystal is prepared by the molten salt method.

3. Use of the dysprosium ion-activated orthophosphate mixed crystal laser crystal according to claim 1, characterized in that, The laser crystal is used as the gain medium of a laser.

4. A solid-state laser in the 565 - 590 nm wavelength band, which is composed of a semiconductor laser pumping system, a laser resonator cavity, and a gain medium, and is characterized in that: The laser crystal as described in claim 1 is used as the gain medium of the solid laser; the semiconductor laser pumping system includes a light source emitting at a wavelength in the 450 nm band and an optical coupler placed between the light source and the resonator; the laser resonator is composed of an input mirror and an output mirror; the input mirror is designed to have a transmittance T≥80% in the 450 nm band and a transmittance T≤0.5% in the 565 - 590 nm band; the output mirror is designed to have a transmittance 0.5%≤T≤10% in the 565 - 590 nm band.

5. The solid-state laser according to claim 4, characterized in that: The input mirror and the output mirror are respectively directly coated on one or two opposite end faces of the gain medium.

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