A ytterbium-doped silicate broadband emission laser crystal, a preparation method thereof, and an application thereof

Abstract

The present invention discloses a ytterbium-doped silicate broadband emission laser crystal, a preparation method thereof and an application thereof, relating to the technical field of laser crystal gain materials. The chemical formula of the crystal is Yb 4y CaRe 4x La 4(1‑x‑y) Si3O 13 , wherein Re is one of Y 3+ , Gd 3+ , Lu 3+ , Sc 3+ , x = 0.01 to 0.50, and y = 0.01 to 0.30. By using such a crystal as a gain medium and pumping with a laser having a central emission wavelength in the range of 940 to 980 nanometers, high-efficiency tunable and ultrashort pulse laser output near 1 micrometer can be achieved, and it has important application prospects in the fields of industrial applications, scientific research, national defense and military, etc.

Description

Technical Field

[0001] The present invention relates to the technical field of laser crystal gain materials, and particularly relates to a ytterbium-doped silicate broadband emission laser crystal, a preparation method thereof, and an application thereof. Background Art

[0002] Among all the current ultrafast laser crystals capable of realizing LD-pumped all-solid-state femtosecond laser output, laser crystal materials doped with Yb 3+ have attracted much attention. The reasons are as follows: (1) Yb3+ has only two electron energy levels (ground state 2F7 / 2 and excited state 2F5 / 2), and its laser operation belongs to a quasi-three-level system, which can effectively avoid defects such as concentration quenching, excited state absorption, and upconversion; (2) Due to the simple energy levels, it can emit a relatively wide fluorescence spectrum, supporting the generation of ultrashort pulses; (3) Its absorption wavelength matches the output wavelength of semiconductor lasers, and semiconductor lasers can be directly used for pumping. And high-performance femtosecond laser crystal materials need to meet a basic requirement: a wide emission spectral bandwidth (which is beneficial to realizing ultrashort pulses).

[0003] In the internal structure of disordered crystals, since luminescent ions randomly occupy different positions in the lattice, compared with traditional ordered crystals, they have a wider inhomogeneous broadening fluorescence spectrum, which is beneficial to the generation of ultrashort pulses. At the same time, the absorption spectrum is also broadened to a certain extent compared with traditional ordered crystals, which makes disordered crystals have good application scenarios in the research of laser crystals. In addition, its own physical and chemical properties are also relatively excellent, attracting the attention of many researchers. Summary of the Invention

[0004] The first object of the present invention is to provide a ytterbium-doped silicate broadband emission laser crystal. This is a laser crystal material that generates 1-micron ultrashort pulses, and the material has a greater degree of disorder, and it is more conducive to generating ultrashort pulsed lasers through mode-locking technology.

[0005] The second object of the present invention is to provide a preparation method of the above-mentioned ytterbium-doped silicate broadband emission laser crystal.

[0006] The third object of the present invention is to provide an application of the above-mentioned ytterbium-doped silicate broadband emission laser crystal.

[0007] The first object of the present invention can be achieved by the following technical solutions:

[0008] A ytterbium-doped silicate broadband emission laser crystal, the chemical formula of the laser crystal is Yb 4y CaRe 4x La 4(1-x-y) Si3O 13 , wherein Re is Y 3+ , Gd 3+, Lu 3+ , Sc 3+ Any one of 3+ and 3+ , where x = 0.01 - 0.50 and y = 0.01 - 0.30. Preferably, x = 0.1 - 0.2 and y = 0.05 - 0.08.

[0009] Furthermore, in the laser crystal, the La element is partially replaced by any one of Re (Y 3+ , Gd 3+ , Lu 3+ , Sc 3+ ), and at the same time, the La and Re elements are partially replaced by Yb 3+ .

[0010] The second object of the present invention can be achieved by the following technical solutions:

[0011] For the preparation method of the above ytterbium-doped silicate broadband emission laser crystal, the laser crystal can be grown by the Czochralski method, including the following steps:

[0012] 1) Select Yb2O3, CaCO3, La2O3, Re2O3, SiO2 as raw materials, and proportion the raw materials according to the following chemical equation; the Re2O3 refers to any one of Y2O3, Gd2O3, Lu2O3, Sc2O3;

[0013] 2yYb2O3 + CaCO3 + 2(1 - x - y)La2O3 + 2xRe2O3 + 3SiO2 → Yb 4y CaRe 4x La 4(1-x-y) Si3O 13 +CO2↑;

[0014] 2) Mix the raw materials proportioned in step 1) evenly, press them into blocks, and calcine to obtain a sintered material;

[0015] 3) Perform crystal growth by the Czochralski method:

[0016] The operation is as follows: Place the sintered material obtained in step 2) in a reactor, heat it to above the melting point to completely melt it, perform isothermal treatment, and then carry out crystal growth; after crystal growth is completed, cool it to room temperature, take out the crystal, and the target product is obtained.

[0017] Furthermore, in step 2), the calcination conditions are set as follows: the sintering temperature is 1200 - 1400 °C, and the sintering time is 4 - 24 hours.

[0018] Furthermore, in step 3), heating to above the melting point specifically means heating to 60 - 120 °C above the melting point.

[0019] Further, in the step 3), the time for the constant temperature treatment is 1 to 12 hours.

[0020] Further, in the step 3), during the crystal growth process, the pulling speed is 0.2 to 5.0 mm / h, and the rotation speed is 5 to 50 rpm.

[0021] Further, in the step 3), during the cooling process, the annealing rate is 8 to 20 °C / h.

[0022] Further, in the step 1), the purity of all raw materials reaches 99.999%.

[0023] The third object of the present invention can be achieved by the following technical solutions:

[0024] For the application of the above ytterbium-doped silicate broadband emission laser crystal, the laser crystal is used to generate ultrafast laser pulses in a 1-μm band all-solid-state mode-locked laser.

[0025] An all-solid-state mode-locked laser uses the above ytterbium-doped silicate broadband emission laser crystal as a laser working medium, and uses a flash lamp or a laser diode as a pump source.

[0026] Further, the central emission wavelength of the pump source is in the range of 940 to 980 nm.

[0027] Further, the output wavelength of the all-solid-state mode-locked laser is in the 1-μm band.

[0028] For the application of the above ytterbium-doped silicate broadband emission laser crystal or all-solid-state mode-locked laser, the application is in the fields of spectroscopy, biochemistry, medicine, military, national defense, etc.

[0029] The present invention has the following advantages and effects compared with the prior art:

[0030] Using such a crystal as a gain medium and pumping with a laser having a central emission wavelength in the range of 940 to 980 nm, high-efficiency tunable and ultrashort pulse laser output near 1 μm can be achieved, which has important application prospects in the fields of industrial applications, scientific research, national defense and military, etc. Specific Embodiments

[0031] The following combines embodiments to further describe in detail the specific embodiments of the present invention. The following embodiments are used to illustrate the present invention, but do not limit the scope of the present invention.

[0032] Embodiment 1

[0033] Weigh the required masses of the raw materials Yb2O3 (99.999%), CaCO3 (99.999%), La2O3 (99.999%), Y2O3 (99.999%), and SiO2 (99.999%) precisely according to the chemical equation of the ratio, where x = 0.1 and y = 0.08. Then put the prepared raw materials into a mixer to mix them evenly, and press the mixed sample into a block and place it in a crucible. Next, place the sample in a muffle furnace for calcination. The sintering temperature is 1200 °C and the sintering time is 8 hours to obtain the sintered material. Place the obtained sintered material in a Czochralski furnace, heat it up to 60 °C above the melting point, completely melt it, and keep it at a constant temperature for 4 hours. Then slowly lower the temperature to the crystallization point for crystal growth. The pulling speed is 1 mm / h and the rotation speed is 10 rpm. When the growth process ends, the crystal is pulled out of the melt and cooled to room temperature at an annealing rate of 12 °C / h, and then the crystal Yb is taken out 0.32 CaY 0.4 La 3.28 Si3O 13 。

[0034] Using such a crystal as the gain medium and pumping it with a laser whose central emission wavelength is in the range of 940 - 980 nm, high-efficiency tunable and ultrashort-pulse laser output near 1 μm can be achieved, which has important application prospects in the fields of industrial applications, scientific research, national defense, and military

[0035] Example 2

[0036] Weigh the required masses of the raw materials Yb2O3 (99.999%), CaCO3 (99.999%), La2O3 (99.999%), Gd2O3 (99.999%), and SiO2 (99.999%) precisely according to the chemical equation of the ratio, where x = 0.2 and y = 0.05. Then put the prepared raw materials into a mixer to mix them evenly, and press the mixed sample into a block and place it in a crucible. Next, place the sample in a muffle furnace for calcination. The sintering temperature is 1250 °C and the sintering time is 9 hours to obtain the sintered material. Place the obtained sintered material in a Czochralski furnace, heat it up to 80 °C above the melting point, completely melt it, and keep it at a constant temperature for 6 hours. Then slowly lower the temperature to the crystallization point for crystal growth. The pulling speed is 1.2 mm / h and the rotation speed is 12 rpm. When the growth process ends, the crystal is pulled out of the melt and cooled to room temperature at an annealing rate of 16 °C / h, and then the crystal Yb is taken out 0.2 CaGd 0.8 La3Si3O 13 。

[0037] Using such a crystal as the gain medium and pumping with a laser whose central emission wavelength is in the range of 940 to 980 nanometers, high-efficiency tunable and ultrashort pulse laser output near 1 micron can be achieved, which has important application prospects in the fields of industrial applications, scientific research, national defense and military, etc.

[0038] The above-described embodiments merely represent several implementation manners of the present invention, and their descriptions are relatively specific and detailed. However, they should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A ytterbium-doped silicate broadband emission laser crystal, characterized in that: The chemical formula of the laser crystal described is Yb 4y CaRe 4x La 4(1-x-y) Si3O 13 , where Re is any one of Y 3+ , Gd 3+ , Lu 3+ , Sc 3+ , x = 0.01 to 0.50, y = 0.01 to 0.

30.

2. The preparation method of the ytterbium-doped silicate broadband emission laser crystal according to claim 1, characterized in that: It includes the following steps: 1) Select Yb2O3, CaCO3, La2O3, Re2O3, SiO2 as raw materials, and proportion the raw materials according to the following chemical equation; the Re2O3 refers to any one of Y2O3, Gd2O3, Lu2O3, Sc2O3; 2Yb2O3 + CaCO3 + 2(1 - x - y)La2O3 + 2xRe2O3 + 3SiO2 → Yb 4y CaRe 4x La 4(1-x-y) Si3O 13 + CO2↑; 2) Mix the raw materials proportioned in step 1) evenly, press them into blocks, and calcine to obtain a sintered material; 3) Adopt the Czochralski method for crystal growth: The operation is as follows: Place the sintered material obtained in step 2) in a reactor, heat it to above the melting point to completely melt it, perform isothermal treatment, and then carry out crystal growth; after the crystal growth is completed, cool it to room temperature and take out the crystal to obtain the target product.

3. The preparation method of the ytterbium-doped silicate broadband emission laser crystal according to claim 2, wherein: In step 2), the calcination conditions are set as follows: the sintering temperature is 1200 - 1400 °C, and the sintering time is 4 - 24 hours.

4. The preparation method of the ytterbium-doped silicate broadband emission laser crystal according to claim 2, wherein: In step 3), heating to above the melting point specifically means heating to 60 - 120 °C above the melting point; In step 3), the isothermal treatment time is 1 - 12 hours; In step 3), during the crystal growth process, the pulling speed is 0.2 - 5.0 mm / h, and the rotation speed is 5 - 50 rpm; In step 3), during the cooling process, the annealing rate is 8 - 20 °C / h.

5. The preparation method of the ytterbium-doped silicate broadband emission laser crystal according to claim 2, wherein: In step 1), the purity of all raw materials reaches 99.999%.

6. Use of the ytterbium-doped silicate broadband emission laser crystal according to claim 1, characterized in that: The laser crystal is used to generate ultrafast laser pulses in a 1-μm band all-solid-state mode-locked laser.

7. An all-solid-state mode-locked laser, wherein: The ytterbium-doped silicate broadband emission laser crystal described in claim 1 is used as the laser working medium, and a flash lamp or a laser diode is used as the pump source.

8. The all-solid-state mode-locked laser according to claim 7, wherein: The central emission wavelength of the pump source is 940 - 980 nm.

9. The all-solid-state mode-locked laser according to claim 7, wherein: The output wavelength of the all-solid-state mode-locked laser is in the 1-μm band.

10. The application of the all-solid-state mode-locked laser according to any one of claims 7 - 9 in the fields of spectroscopy, biochemistry, medicine, military or national defense.