Erbium-doped silicate crystals and 1.5 μm lasers using the same

Abstract

A class of erbium-doped silicate crystals have a general chemical formula of (Er.sub.xYb.sub.yCe.sub.zA.sub.(1-x-y-z)).sub.3RM.sub.3Si.sub.2O.sub.14, in which the range of x is 0.002 to 0.02, y is 0.005 to 0.1, and z is 0 to 0.15; A is one, two or three elements selected from Ca, Sr, or Ba; R is one or two elements selected from Nb or Ta; M is one or two elements selected from Al or Ga. Using one of such crystals as a gain medium and a diode laser at 940 nm or 980 nm as a pumping source, a 1.5 μm continuous-wave solid-state laser with high output power and high efficiency, as well as a pulse solid-state laser with high energy and narrow width can be obtained.

Claims

1. An erbium-doped silicate crystal having a general chemical formula of (Er.sub.xYb.sub.yCe.sub.zA.sub.(1-x-y-z)).sub.3RM.sub.3Si.sub.2O.sub.14, wherein x is 0.002 to 0.02, y is 0.005 to 0.10, z is 0 to 0.15; A is selected from Sr, Ba, and combinations thereof; R is selected from Nb, Ta, and combinations thereof; and M is selected from Al, Ga, and combinations thereof.

2. The erbium-doped silicate crystal of claim 1 belongs to a trigonal crystal system and is P321 space group.

3. A method of preparing the erbium-doped silicate crystal of claim 1, comprising: S1: mixing and grinding a compound containing Er, a compound containing Yb, a compound containing Ce, a compound containing A, a compound containing R, a compound containing M, and a compound containing S1; S2: sintering a mixture obtained from step S1 to obtain a polycrystalline material; and S3: carrying out a crystal growth of the polycrystalline material obtained in step S2; wherein, the A, R, M are defined in claim 1, wherein, in step S1, the compound containing Er is selected from oxides of Er and Er.sub.2O.sub.3; the compound containing Yb is selected from oxides of Yb and Yb.sub.2O.sub.3; the compound containing Ce is selected from oxides of Ce and CeO.sub.2; the compound containing Si is selected from oxides of Si and SiO.sub.2; the compound containing A is selected from carbonates of A, SrCO.sub.3, BaCO.sub.3, and combinations thereof, and the compound containing R is selected from oxides of R, Nb.sub.2O.sub.5, Ga.sub.2O.sub.3, and combinations thereof.

4. The method of claim 3, wherein, in step S2, the sintering temperature is 1100 to 1250° C.

5. The method of claim 3, wherein, in step S3, the growth temperature is 1200 to 1400° C., and in the process of crystal growth, a pulling speed of the crystal is 0.6 to 1.5 mm/h, and a rotation rate for the crystal is 6 to 15 rpm.

6. The method of claim 3, wherein, when M is Ga, step S1 comprises: mixing and grinding the compound containing Er, the compound containing Yb, the compound containing Ce, the compound containing A, the compound containing R, a first amount of the compound containing Ga, and the compound containing Si to obtain a first mixture; adding a second amount of the compound containing Ga to the first mixture and then grinding to obtain the mixture, wherein the second amount of the compound containing Ga is 0.5 mol % to 2.5 mol % of the first amount of the compound containing Ga.

7. The method of claim 6, wherein the second amount of the compound containing Ga is 1.2 mol % of the first amount of the compound containing Ga.

8. A laser, comprising: a laser gain medium that is the erbium-doped silicate crystal according to claim 1, a laser oscillator, and a laser amplifier.

9. The laser of claim 8, having a wavelength of 1.5 μm, wherein the laser is a 1.5 μm pulse solid-state laser, a 1.5 μm tunable solid-state laser, a 1.5 μm frequency-doubled, or a 1.5 μm self-frequency-doubled solid-state laser.

10. A laser comprises a diode laser pumping system, an input mirror, a gain medium, and an output mirror; the gain medium is the erbium-doped silicate crystal of claim 1; the diode laser pumping system comprises a 940 nm or 980 nm diode laser and an optical coupler; the gain medium is located between the input mirror and the output mirror.

11. The laser of claim 10, wherein the laser further comprises a 1.5 μm Q-switching or a mode-locking element located between the gain medium and the output mirror, or the Q-switching and the mode-locking element are placed between the gain medium and the output mirror, the input mirror is directly deposited on the input surface of the gain medium, and the output mirror is directly deposited on the output surface of the Q-switching or the mode-locking element, wherein the Q-switching element is selected from a passively Q-switched crystal, a Co.sup.2+: MgAl.sub.2O.sub.4 crystal, a Co.sup.2+: ZnSe crystal, a Cr.sup.2+: ZnSe crystal, and an acousto-optic Q-switched module.

12. The laser of claim 10, wherein the laser further comprises a wavelength-tunable element around 1.5 μm located between the gain medium and the output mirror, and wherein the wavelength-tunable element is a birefringent filter, a grating, or a prism.

13. The laser of claim 10, wherein the laser further comprises a 1.5 μm frequency-doubling crystal.

14. The laser of claim 10, wherein the laser is a 1.5 μm self-frequency-doubled solid-state laser using the gain medium as a self-frequency-doubling laser crystal, wherein a cut angle of the self-frequency-doubling laser crystal is a frequency-doubling phase-matching angle of an emitted fundamental 1.5 μm laser; the input mirror has a transmission T≥70% at 980 nm, and T≤0.5% at 1.5 μm and in the frequency-doubled waveband; the output mirror has a transmission T 0.5% at 1.5 μm, and T≥70% in the frequency-doubled waveband.

15. The laser of claim 10, wherein the optical coupler is arranged between the diode laser and the input mirror, wherein the input mirror has a transmission T≥70% in a pump waveband, and T≤0.5% at 1.5 μm, and the output mirror has a transmission 0.5% T≤10% at 1.5 μm, wherein the input mirror and the output mirror are disposed on the input surface of the gain medium and on the output surface of the gain medium, respectively.

16. The erbium-doped silicate crystal of claim 1, wherein R is Ta.

17. An erbium-doped silicate crystal having a general chemical formula of (Er.sub.xYb.sub.yCe.sub.zA.sub.(1-x-y-z)).sub.3RM.sub.3Si.sub.2O.sub.14, wherein x is 0.002 to 0.02, y is 0.005 to 0.10, z is 0 to 0.15; A is selected from Ca, Sr, Ba, and combinations thereof; R is selected from Nb, Ta, and combinations thereof, and M is Al.

18. A laser, comprising: a laser gain medium that is the erbium-doped silicate crystal according to claim 17, a laser oscillator, and a laser amplifier.

19. The laser of claim 18, having a wavelength of 1.5 μm, wherein the laser is a 1.5 μm pulse solid-state laser, a 1.5 μm tunable solid-state laser, a 1.5 μm frequency-doubled, or a 1.5 μm self-frequency-doubled solid-state laser.

20. A laser comprises a diode laser pumping system, an input mirror, a gain medium, and an output mirror; the gain medium is the erbium-doped silicate crystal of claim 18; the diode laser pumping system comprises a 940 nm or 980 nm diode laser and an optical coupler; the gain medium is located between the input mirror and the output mirror.

21. The laser of claim 20, wherein the laser further comprises a 1.5 μm Q-switching or a mode-locking element located between the gain medium and the output mirror, or the Q-switching and the mode-locking element are placed between the gain medium and the output mirror, the input mirror is directly deposited on the input surface of the gain medium, and the output mirror is directly deposited on the output surface of the Q-switching or the mode-locking element, wherein the Q-switching element is selected from a passively Q-switched crystal, a Co.sup.2+: MgAl.sub.2O.sub.4 crystal, a Co.sup.2+: ZnSe crystal, a Cr.sup.2+: ZnSe crystal, and an acousto-optic Q-switched module.

22. The laser of claim 20, wherein the laser further comprises a wavelength-tunable element around 1.5 μm located between the gain medium and the output mirror, and wherein the wavelength-tunable element is a birefringent filter, a grating, or a prism.

23. The laser of claim 20, wherein the laser further comprises a 1.5 μm frequency-doubling crystal.

24. The laser of claim 20, wherein the laser is a 1.5 μm self-frequency-doubled solid-state laser using the gain medium as a self-frequency-doubling laser crystal, wherein a cut angle of the self-frequency-doubling laser crystal is a frequency-doubling phase-matching angle of an emitted fundamental 1.5 μm laser; the input mirror has a transmission T≥70% at 980 nm, and T≤0.5% at 1.5 μm and in the frequency-doubled waveband; the output mirror has a transmission T≤0.5% at 1.5 μm, and T≥70% in the frequency-doubled waveband.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a picture of the (Er.sub.0.007Yb.sub.0.02Ce.sub.0.03Ca.sub.0.943).sub.3NbGa.sub.3Si.sub.2O.sub.14 crystal in Example 4.

(2) FIG. 2 shows XRD pattern of the (Er.sub.0.007Yb.sub.0.02Ce.sub.0.03Ca.sub.0.943).sub.3NbGa.sub.3Si.sub.2O.sub.14 crystal in Example 4.

(3) FIG. 3A to FIG. 3E show exemplary laser systems of the current disclosure.

(4) The reference numerals in the figures are: 1. 940 nm or 980 nm diode laser; 2. optical coupler; 3. input mirror; 4. gain medium; 5. output mirror; 6. Q-switching or mode-locking element 7. wavelength-tunable element 8. frequency-doubling crystal; self-frequency-doubling laser crystal.

EXAMPLES

(5) The crystals and lasers of the disclosure will be further described in the following in combination with specific embodiments. It should be understood that the following embodiments exemplarily illustrate and explain the disclosure, and should not be interpreted to limit the protection scope of the disclosure. The technologies implemented based on the above-described contents disclosed herein all fall into the protection scope of the disclosure.

(6) Unless otherwise specified, the raw materials and reagents used in the following examples are all commercially available products, or can be prepared by known methods.

EXAMPLE 1

(7) An (Er.sub.0.005Yb.sub.0.01Ca.sub.0.985).sub.3NbGa.sub.3Si.sub.2O.sub.14 crystal end-pumped by a 976 nm diode laser realizing a solid-state laser at 1.56 μm.

(8) An (Er.sub.0.005Yb.sub.0.01Ca.sub.0.985).sub.3NbGa.sub.3Si.sub.2O.sub.14 crystal was grown by the Czochralski method, and the specific preparation steps were as follows:

(9) (1) Use CaCO.sub.3, Er.sub.2O.sub.3, Yb.sub.2O.sub.3, Nb.sub.2O.sub.5, Ga.sub.2O.sub.3 and SiO.sub.2 as raw materials, which are mixed together according to the stoichiometric ratio of the crystal formula.

(10) (2) Add Ga.sub.2O.sub.3 to the mixture obtained in step (1), the addition amount being 1.2 mol % of Ga.sub.2O.sub.3 in step (1).

(11) (3) Grind the mixture for 16 hours, and then press the uniformly ground mixture into tablets; sinter the tablets at 1150° C. for 30 hours, and synthesize to obtain a polycrystalline material after complete reaction.

(12) (4) Put the polycrystalline material into a single crystal growth furnace for carrying out the crystal growth, a growth temperature being 1300° C., a rotation rate being 12 rpm, and a pulling speed being 1.0 mm/h. After the crystal grew to the required size, pull the crystal of f the liquid surface and cool down, a cooling rate being 20° C./h, and then take the crystal out after the temperature in the furnace dropped to room temperature.

(13) The crystal belongs to the trigonal crystal system, the space group is P321, the crystal is uniaxial, and its optical axis is parallel to the crystallographic c-axis. After orientation by using a polarized light microscope, a crystal sample having a pair of smooth surfaces perpendicular to the c-axis was cut and polished. Because the absorption coefficient at pumping wave length of 976 nm is about 3.0 cm.sup.−1, a 4.0 mm-thick crystal sample (the area of the surface is generally square millimeters to square centimeters) has 70% absorption efficiency. The crystal sample was fixed in a copper chamber with a small hole in the middle of front and rear ends. The chamber was placed in a laser cavity. The input mirror of the laser cavity had a transmission of 90% at 976 nm, and 0.1% at 1.56 μm; the output mirror of the laser cavity had a transmission of 3.0% at 1.56 μm. When end-pumped by a 6 W diode laser at 976 nm, a solid-state laser at 1.56 μm with a continuous-wave output power of more than 500 mW was obtained. The input and output mirrors of the laser cavity can be directly deposited on the input and/or output surfaces of the laser crystal, respectively, to achieve the same purpose.

EXAMPLE 2

(14) An (Er.sub.0.006Yb.sub.0.015Ca.sub.0.979).sub.3TaGa.sub.3Si.sub.2O.sub.14 crystal end-pumped by a 976 nm diode laser realizing a solid-state laser at 1.56 μm.

(15) An (Er.sub.0.006Yb.sub.0.015Ca.sub.0.979).sub.3TaGa.sub.3Si.sub.2O.sub.14 crystal was grown by the Czochralski method, and the specific preparation method was referred to Example 1. The crystal is uniaxial, and its optical axis is parallel to the crystallographic c-axis. After orientation by using a polarized light microscope, a crystal sample having a pair of smooth surfaces perpendicular to the c-axis was cut and polished. Because the absorption coefficient at pumping wavelength of 976 nm is about 3.8 cm.sup.−1, a 3.2 mm-thick crystal sample (the area of the surface is generally square millimeters to square centimeters) has 70% absorption efficiency. The crystal sample was fixed in a copper chamber with a small hole in the middle of front and rear ends. The chamber was placed in a laser cavity. The input mirror of the laser cavity had a transmission of 90% at 976 nm, and 0.1% at 1.56 μm; the output mirror of the laser cavity had a transmission of 2.0% at 1.56 μm. When end-pumped by a 6 W diode laser at 976 nm, a solid-state laser at 1.56 μm with a continuous-wave output power of more than 400 mW was obtained. The input and output mirrors of the laser cavity can be directly deposited on the input and/or output surfaces of the laser crystal, respectively, to achieve the same purpose.

EXAMPLE 3

(16) An (Er.sub.0.01Yb.sub.0.03Sr.sub.0.96).sub.3TaGa.sub.3Si.sub.2O.sub.14 crystal end-pumped by a 976 nm diode laser realizing a solid-state laser at 1.58 μm.

(17) An (Er.sub.0.01Yb.sub.0.03Sr.sub.0.96).sub.3TaGa.sub.3Si.sub.2O.sub.14 crystal was grown by the Czochralski method, and the specific preparation method was referred to Example 1. The crystal is uniaxial, and its optical axis is parallel to the crystallographic c axis. After orientation by using a polarized light microscope, a crystal sample having a pair of smooth surfaces perpendicular to the c-axis was cut and polished. Because the absorption coefficient at pumping wavelength of 976 nm is about 7.5 cm.sup.−1, a 2.1 mm-thick crystal sample (the area of the surface is generally square millimeters to square centimeters) has 80% absorption efficiency. The crystal sample was fixed in a copper chamber with a small hole in the middle of front and rear ends. The chamber was placed in a laser cavity. The input mirror of the laser cavity had a transmission of 90% at 976 nm, and 0.1% at 1.58 μm; the output mirror of the laser cavity had a transmission of 1.0% at 1.58 μm. When end-pumped by a 6 W diode laser at 976 nm, a solid-state laser at 1.58 μm with a continuous-wave output power of more than 200 mW was obtained. The input and output mirrors of the laser cavity can be directly deposited on the input and/or output surfaces of the laser crystal, respectively, to achieve the same purpose.

EXAMPLE 4

(18) An (Er.sub.0.007Yb.sub.0.02Ce.sub.0.03Ca.sub.0.943).sub.3NbGa.sub.3Si.sub.2O.sub.14 crystal end-pumped by a 976 nm diode laser realizing a solid-state laser at 1.56 μm.

(19) An (Er.sub.0.007Yb.sub.0.02Ce.sub.0.03Ca.sub.0.943).sub.3NbGa.sub.3Si.sub.2O.sub.14 crystal was grown by the Czochralski method, and the specific preparation method was referred to Example 1. The picture of the (Er.sub.0.007Yb.sub.0.02Ce.sub.0.03Ca.sub.0.943).sub.3NbGa.sub.3Si.sub.2O.sub.14 crystal is shown in FIG. 1, and its XRD pattern is indicated in FIG. 2.

(20) The crystal is uniaxial, and its optical axis is parallel to the crystallographic c-axis. After orientation by using a polarized light microscope, a crystal sample having a pair of smooth surfaces perpendicular to the c-axis was cut and polished. Because the absorption coefficient at pumping wavelength of 976 nm is about 4.0 cm.sup.−1, a 3.0 mm-thick crystal sample (the area of the surface was generally square millimeters to square centimeters) has 70% absorption efficiency. The crystal sample was fixed in a copper chamber with a small hole in the middle of front and rear ends. The chamber was placed in a laser cavity. The input mirror of the laser cavity had a transmission of 90% at 976 nm, and 0.1% at 1.56 μm; the output mirror of the laser cavity had a transmission of 3.4% at 1.56 μm. When end-pumped by a 6 W diode laser at 976 nm, a solid-state laser at 1.56 μm with a continuous-wave output power of more than 600 mW was obtained. The input and output mirrors of the laser cavity can be directly deposited on the input and/or output surfaces of the laser crystal, respectively, to achieve the same purpose.

EXAMPLE 5

(21) An (Er.sub.0.005Yb.sub.0.04Ce.sub.0.06Ca.sub.0.895).sub.3TaAl.sub.3Si.sub.2O.sub.14 crystal end-pumped by a 976 nm diode laser realizing a solid-state laser at 1.56 μm.

(22) An (Er.sub.0.005Yb.sub.0.04Ce.sub.0.06Ca.sub.0.895).sub.3TaAl.sub.3Si.sub.2O.sub.14 crystal was grown by the Czochralski method, and the specific preparation method was similar to that in Example 1, except that in step (1) the raw material Al.sub.2O.sub.3 was proportioned in the stoichiometric ratio of the crystal, and step (2) for adding Al.sub.2O.sub.3 was not necessary. The crystal is uniaxial, and its optical axis is parallel to the crystallographic c-axis. After orientation by using a polarized light microscope, a crystal sample having a pair of smooth surfaces perpendicular to the c-axis was cut and polished. Because the absorption coefficient at pumping wavelength of 976 nm is about 10 cm.sup.−1, a 1.5 mm-thick crystal sample (the area of the surface was generally square millimeters to square centimeters) has 78% absorption efficiency. The crystal sample was fixed in a copper chamber with a small hole in the middle of front and rear ends. The chamber was placed in a laser cavity. The input mirror of the laser cavity had a transmission of 90% at 976 nm, and 0.1% at 1.56 μm; the output mirror of the laser cavity had a transmission of 2.7% at 1.56 μm. When end-pumped by a 6 W diode laser at 976 nm, a solid-state laser at 1.56 μm with a continuous-wave output power of more than 500 mW was obtained. The input and output mirrors of the laser cavity can be directly deposited on the input and/or output surfaces of the laser crystal, respectively, to achieve the same purpose.

EXAMPLE 6

(23) An (Er.sub.0.012Yb.sub.0.08Ce.sub.0.13Sr.sub.0.778).sub.3NbGa.sub.3Si.sub.2O.sub.14 crystal end-pumped by a 976 nm diode laser realizing a solid-state laser at 1.56 μm.

(24) An (Er.sub.0.012Yb.sub.0.08Ce.sub.0.13Sr.sub.0.778).sub.3NbGa.sub.3Si.sub.2O.sub.14 crystal was grown by the Czochralski method, and the specific preparation method was referred to Example 1. The crystal is uniaxial, and its optical axis is parallel to the crystallographic c axis. After orientation by using a polarized light microscope, a crystal sample having a pair of smooth surfaces perpendicular to the c-axis was cut and polished. Because the absorption coefficient at pumping wavelength of 976 nm is about 20 cm.sup.−1, a 1.0 mm-thick crystal sample (the area of the surface was generally square millimeters to square centimeters) has 86% absorption efficiency. The crystal sample was fixed in a copper chamber with a small hole in the middle of front and rear ends. The chamber was placed in a laser cavity. The input mirror of the laser cavity had a transmission of 90% at 976 nm, and 0.1% at 1.56 m; the output mirror of the laser cavity had a transmission of 4.2% at 1.56 μm. When end-pumped by a 6 W diode laser at 976 nm, a solid-state laser at 1.56 μm with a continuous-wave output power of more than 500 mW was obtained. The input and output mirrors of the laser cavity can be directly deposited on the input and/or output surfaces of the laser crystal, respectively, to achieve the same purpose.

EXAMPLE 7

(25) An (Er.sub.0.007Yb.sub.0.02Ce.sub.0.03Ca.sub.0.943).sub.3NbAl.sub.3Si.sub.2O.sub.14 crystal end-pumped by a 976 nm diode laser realizing a solid-state laser at 1.56 μm.

(26) An (Er.sub.0.007Yb.sub.0.02Ce.sub.0.03Ca.sub.0.943).sub.3NbAl.sub.3Si.sub.2O.sub.14 crystal was grown by the Czochralski method, and the specific preparation method was similar to that in Example 1, except that in step (1) the raw material Al.sub.2O.sub.3 was proportioned in the stoichiometric ratio of the crystal, and step (2) for adding Al.sub.2O.sub.3 was not necessary. The crystal is uniaxial, and its optical axis is parallel to the crystallographic c axis. After orientation by using a polarized light microscope, a crystal sample having a pair of smooth surfaces perpendicular to the c-axis was cut and polished. Because the absorption coefficient at pumping wavelength of 976 nm is about 4.0 cm.sup.1, a 3.0 mm-thick crystal sample (the area of the surface was generally square millimeters to square centimeters) has 70% absorption efficiency. The crystal sample was fixed in a copper chamber with a small hole in the middle of front and rear ends. The chamber was placed in a laser cavity. The input mirror of the laser cavity had a transmission of 90% at 976 nm, and 0.1% at 1.56 μm; the output mirror of the laser cavity had a transmission of 3.4% at 1.56 μm. When end-pumped by a 6 W diode laser at 976 nm, a solid-state laser at 1.56 μm with a continuous-wave output power of more than 600 mW was obtained. The input and output mirrors of the laser cavity can be directly deposited on the input and/or output surfaces of the laser crystal, respectively, to achieve the same purpose.

EXAMPLE 8

(27) An Er.sup.3+-doped silicate crystal end-pumped by a 976 nm diode laser realizing a pulse solid-state laser near 1.56 μm.

(28) When a 1.5 μm passively Q-switched crystal (such as a Co.sup.2+:MgAl.sub.2O.sub.4 crystal, a Co.sup.2+:ZnSe crystal, a Cr.sup.2+:ZnSe crystal, etc.), or an acousto-optic Q-switched module was directly inserted between anyone laser crystal of Examples 1 to 7 and the output mirror, a Q-switched pulse laser near 1.56 μm could be realized. The input mirror can further be directly deposited on the input surface of the gain medium, and the output mirror can be directly deposited on the output surface of the Q-switching or mode-locking element, respectively, to achieve the same purpose.

EXAMPLE 9

(29) An Er.sup.3+-doped silicate crystal end-pumped by a 976 nm diode laser realizing a tunable solid-state laser between 1530-1580 nm.

(30) Any one laser crystal of Examples 1 to 7 was fixed in a copper chamber with a small hole in the middle of front and rear ends. The chamber was placed in a laser cavity. The input mirror of the laser cavity had a transmission of 90% at 976 nm, and 0.1% between 1.5-1.6 μm; the output mirror of the laser cavity had a transmission of 1.0% between 1.5-1.6 μm. A tunable element around wavelength of 1.5 μm (such as a birefringent filter, a grating, a prism, etc.) was inserted between the laser crystal and the output mirror of the laser cavity to achieve a tunable solid-state laser at 1530-1580 nm when the laser crystal was end-pumped by a 976 nm diode laser.

EXAMPLE 10

(31) An Er.sup.3+-doped silicate crystal end-pumped by a 976 nm diode laser realizing a frequency-doubled solid-state laser at 790 nm.

(32) A nonlinear optical crystal for a 1.5 μm frequency-doubled laser (such as a K TP crystal, an LBO crystal, a β-BBO crystal, etc.) was directly inserted between any one laser crystal of Examples 1 to 7 and the output mirror. The input mirror of the laser cavity had a transmission of 90% at 976 nm, and 0.1% at 1.58 μm and 790 nm; the output mirror had a transmission of 0.3% at 1580 nm and 80% at 790 nm. A frequency-doubled laser at 790 nm could be achieved when the the laser crystal was end-pumped by a 976 nm diode laser. The input mirror can further be directly deposited on the input surface of the gain medium, and the output mirror can be directly deposited on the output surface of the nonlinear optical crystal, respectively, to achieve the same purpose.

EXAMPLE 11

(33) An (Er.sub.0.007Yb.sub.0.02Ce.sub.0.03Ca.sub.0.943).sub.3NbGa.sub.3Si.sub.2O.sub.14 crystal end-pumped by a 976 nm diode laser realizing a self-frequency-doubled solid-state laser at 790 nm.

(34) The (Er.sub.0.007Yb.sub.0.02Ce.sub.0.03Ca.sub.0.943).sub.3NbGa.sub.3Si.sub.2O.sub.14 laser crystal in Example 4 was used as a self-frequency-doubling crystal, which was fixed in a copper chamber with a small hole in the middle of front and rear ends. The chamber was placed in a laser cavity. The cut angles of the type I phase-matching direction of the self-frequency-doubling crystal were 0=27.5°, o=30°. The input mirror of the laser cavity had a transmission of 90% at 976 nm, and 0.1% at 1.58 μm and 790 nm; the output mirror had a transmission of 0.3% at 1.58 μm and 80% at 790 nm. A self-frequency-doubled laser at 790 nm could be achieved when the laser crystal was end-pumped by a 976 nm diode laser. The input and output mirrors of the laser cavity can be directly deposited on the input and/or output surfaces of the self-frequency-doubling laser crystal, respectively, to achieve the same purpose.

(35) The embodiments of the disclosure are described above. However, the disclosure is not limited to the above-described embodiments. Any modification, equivalent alternative, improvement, etc., made within the spirit and principles of the disclosure, are intended to be included within the scope of the disclosure.