CN211859139U

CN211859139U - All-solid-state femtosecond laser of Kerr mode-locked ytterbium-doped lanthanum gadolinium silicate crystal

Info

Publication number: CN211859139U
Application number: CN202020962609.8U
Authority: CN
Inventors: 孙艳秋; 权岚; 俞海云
Original assignee: Ma'anshan Huayu Environmental Protection Equipment Manufacturing Co ltd
Current assignee: Ma'anshan Huayu Environmental Protection Equipment Manufacturing Co ltd
Priority date: 2020-05-29
Filing date: 2020-05-29
Publication date: 2020-11-03
Anticipated expiration: 2030-05-29

Abstract

The utility model discloses a Kerr mode locking mixes full solid-state femto second laser of ytterbium gadolinium lanthanum silicate crystal belongs to functional crystal material laser output technical field. The utility model discloses an all-solid-state femtosecond laser of Kerr mode-locked ytterbium-doped gadolinium lanthanum silicate crystal, which comprises a pump, wherein a pumping light source output horizontally by the pump is emitted to a focusing lens through an optical fiber coupler; the pump light source is focused by the focusing lens to be a focusing light source, and is transmitted to the concave mirror II through the Yb crystal, and then is oscillated in a resonant cavity formed by the concave mirror I, the concave mirror II and the plane reflecting mirror to realize laser output; then reflected to an SF6 triple prism through a concave mirror II for compensating the dispersion in the cavity; and finally, the femtosecond pulse laser output is realized through the laser output coupling mirror.

Description

All-solid-state femtosecond laser of Kerr mode-locked ytterbium-doped lanthanum gadolinium silicate crystal

Technical Field

The utility model relates to a functional crystal material laser output technical field, the more specifically all solid-state femtosecond laser that Kerr mode locking mixes ytterbium gadolinium lanthanum silicate crystal that says so.

Background

In 1981, the first femtosecond dye laser appeared in the world, which marks the development of ultrafast laser to the femtosecond (10-15s) stage, and thus the femtosecond laser technology and science are generated. The femtosecond laser plays an important role in the fields of ultrafast time-resolved spectroscopy, biomedical science, optical clocks, metering, microelectronic processing, high-capacity optical communication and the like in a very short time after birth due to the characteristics of the femtosecond laser, such as ultrashort pulse, high peak power, wide spectrum and the like. In 1991, the first international femtosecond titanium gem laser emerged to mark the new era of femtosecond laser entering solid femtosecond laser, which is characterized in that: the emission spectrum is broader than the dye emission spectrum, providing a narrower pulse width and greater saturation intensity and more stable optical performance. In recent years, with the birth and development of a series of revolutionary technologies such as chirped pulse amplification technology (acquiring 2018 Nobel prize for physics), mode locking technology, laser Q-switching technology, LD (laser diode) technology and the like, the limit of the width of all-solid-state femtosecond laser pulses is broken through continuously, the peak power of the laser pulses is improved continuously, and the volume, stability and laser efficiency of the femtosecond laser are improved obviously, so that the femtosecond laser technology becomes one of the most active research frontiers and key competitive fields in the fields of optics, even physics and information science at present.

At present, the commercialized femtosecond laser mainly takes a mode-locked titanium sapphire laser as a main laser, but the absorption peak of the titanium sapphire crystal is positioned in a visible rangeThe wave band can not be directly pumped by LD, and generally only argon ion laser (wavelength 515nm) or Nd can be adopted³⁺Green light (532nm) obtained by frequency doubling of the doped solid laser is used as a pumping source, so that the laser has a complex structure, a large volume and high maintenance cost, and the development and the application of the laser are limited. Compared with the prior art, the LD pump ultrafast laser crystal directly realizes femtosecond laser output, has the advantages of compact structure, high efficiency, good stability and the like, and is an important development direction of the current femtosecond laser.

In all current ultrafast laser crystals capable of realizing LD pumping all-solid-state femtosecond laser output, due to trivalent ytterbium ion (Yb)³⁺) Unique energy level structure, and the like, and doping Yb³⁺The laser medium generally has a relatively strong and wide absorption band in the range of 900-1000nm, can be effectively coupled with the InGaAs (especially around 980 nm) of a commercial laser diode, and simultaneously has the characteristic of broadband emission in the wavelength band of 1000-1100 nm. It is known that a wider absorption band is more beneficial to absorption of pump light, so that the requirement on temperature control of a device can be effectively reduced, and the pumping efficiency is improved, while a wider emission band is more beneficial to obtaining shorter pulse laser output, however, how to realize broadening of the absorption band is a problem that people are constantly searching for. Because the ytterbium-doped laser crystal is very suitable for LD direct pumping and outputs about 1.0 μm femtosecond laser, the ytterbium-doped laser crystal becomes a research hotspot in the field of femtosecond laser since 21 century.

SUMMERY OF THE UTILITY MODEL

1. Technical problem to be solved by the utility model

In the prior art, an argon ion laser (with the wavelength of 515nm) or Nd is generally adopted³⁺The utility model provides an all-solid-state femtosecond laser of Kerr mode-locked Yb-doped gadolinium lanthanum silicate crystal, which takes Yb: GLSO crystal as femtosecond laser medium, adopts femtosecond laser as pump to emit pumping light source with central wavelength in corresponding interval range according to Yb: GLSO crystal transmission spectrogram, focuses on Yb: GLSO crystal end face through fiber coupler and focusing lens, and then transmits Yb: GLSO crystalLaunch on concave mirror II, finally realize femtosecond pulse laser output through laser output coupling mirror, the utility model discloses an efficient advantage such as high, the stability is good of femtosecond laser utensil.

2. Technical scheme

In order to achieve the above purpose, the utility model provides a technical scheme does:

a Kerr mode-locked ytterbium-doped gadolinium lanthanum silicate crystal all-solid-state femtosecond laser comprises a pump, wherein a pump light source output horizontally by the pump is emitted to a focusing lens through an optical fiber coupler; the pump light source is focused into a focusing light source through a focusing lens and is emitted to the concave mirror II through the Yb GLSO crystal, and the concave mirror II reflects the femtosecond laser transmitted in the Yb GLSO crystal to the SF6 triple prism for compensating dispersion in the cavity; the femtosecond laser penetrates through the SF6 triangular prism arranged in pairs and then penetrates through a laser output coupling mirror to realize laser output; according to Yb, GLSO crystal has strong absorption bands at 940nm and 970nm, so that a 940nm or 970nm semiconductor laser mature in the prior art can be used as a pump to emit a pump light source, and the energy of the pump light source is effectively absorbed by the Yb GLSO crystal and then passes through the Yb GLSO crystal²F_7/2→²F_5/2Transition of energy level, Yb³⁺Pumping particles of ground state to²F_5/2At an energy level, then²F_5/2The particles on the energy level are relaxed to²F_5/2At the lowest Stark sublevel, population inversion is formed, thereby realizing²F_5/2To²F_7/2The stimulated transition generates 1.03 micron near infrared laser, and femtosecond pulse laser output is realized in a mode of mode locking; at present, a femtosecond laser mainly uses a mode-locked titanium sapphire laser, but because the absorption peak of a titanium sapphire crystal is positioned in a visible waveband, LD direct pumping cannot be directly adopted, and generally only an argon ion laser (with the wavelength of 515nm) or Nd can be adopted³⁺The green light (532nm) obtained by doping the frequency multiplication of the solid laser is used as a pumping source, so that the structure of the laser is complex, the volume is large, and the maintenance cost is highGood and the like.

The further technical scheme is that the Yb GLSO crystal is wrapped by indium foil and fixed on a red copper water-cooling heat sink, the temperature of the water-cooling heat sink is stabilized to be about 16 ℃ in an active control mode, and then the Yb GLSO crystal is placed in a femtosecond laser at a Brewster angle to reduce the adverse effect of waste heat on laser oscillation; the Yb/GLSO crystal comprises a left end surface, a right end surface and a peripheral side surface, and the left end surface and the right end surface of the Yb/GLSO crystal are polished to have high surface smoothness and keep good parallelism between the two end surfaces; the pump light source is focused into a focusing light source on the right end face of the Yb GLSO crystal, and the focusing light source enters from the right end face of the Yb GLSO crystal, passes through the Yb GLSO crystal and then penetrates out from the left end face of the Yb GLSO crystal; the diameter of a focal spot of the focusing light source focused on the end face of the Yb/GLSO crystal is about 20 microns, the aperture of the pumping emission hole is 22 microns and is larger than the diameter of the focal spot, so that the pumping light source can be completely absorbed by the Yb/GLSO crystal, and mode locking is realized.

According to the further technical scheme, a concave mirror I is further arranged at the position, corresponding to the concave mirror II, on the right side of the Yb/GLSO crystal, an antireflection film with the thickness of 800-1000 nm and a high-reflection film with the thickness of 1000-1200 nm are plated on the surfaces of the concave mirror I and the concave mirror II, laser input into the Yb/GLSO crystal forms an X-type optical resonant cavity through the concave mirror I and the concave mirror II, and the laser oscillated in the X-type optical resonant cavity is reflected by the concave mirror II after the conditions of particle beam inversion and the like are met.

According to the technical scheme, retro-reflection of laser is achieved through the plane reflecting mirror by the laser reflected by the concave mirror I, a high-reflection film with the thickness of 1000-1200 nm is plated on the surface of the plane reflecting mirror, so that retro-reflection of the laser is effectively achieved, when the aperture of the pumping emission hole is smaller than the diameter of a focal spot, the laser in the X-shaped optical resonant cavity continuously vibrates, and therefore the conditions of particle beam reversal and the like are met.

In a further technical scheme, in an experiment, the adjustment of parameters such as the size of a Yb GLSO crystal, the curvature radius, the transmittance of a laser output coupling mirror and the like can influence the efficiency of outputting femtosecond laser and the pulse width of the femtosecond laser, and the size of the Yb GLSO crystal is as follows: the length of the end face is 2-8 mm, the length is 2-6 mm, the curvature radius of the concave mirror I and the concave mirror II is 70-200 mm, and the transmittance of the laser output coupling mirror is 0.2% -1%.

The further technical scheme is that the Yb GLSO crystal is a femtosecond laser crystal which takes gadolinium lanthanum silicate as a matrix and has a monoclinic symmetrical structure; the chemical formula of the Yb/GLSO crystal is Yb³⁺:(GdLa)₂SiO₅Molecular formula Yb_xGd_2-x- _yLa_ySiO₅Wherein 0 is<x<1，0<y<Compared with gadolinium silicate crystals, the gadolinium lanthanum silicate crystals cause larger system disorder due to the introduction of lanthanum ions, and spectral non-uniformity broadening caused by the system disorder can further widen the emission spectral bandwidth, so that gadolinium lanthanum silicate has wider emission spectral bandwidth than the gadolinium silicate crystals, and is expected to realize shorter pulse laser output.

3. Advantageous effects

Adopt the technical scheme provided by the utility model, compare with prior art, have following beneficial effect:

(1) the utility model discloses an all solid-state femtosecond laser of Kerr mode-locked ytterbium-doped gadolinium lanthanum silicate crystal, according to Yb GLSO crystal 940nm and 970nm department have strong absorption band, therefore can adopt the mature 940nm or 970nm semiconductor laser of current technology as sending the pumping light source as the pumping, after the effectual energy that absorbs the pumping light source of Yb GLSO crystal, through the energy of passing through²F_7/2→²F_5/2Transition of energy level, Yb³⁺Pumping particles of ground state to²F_5/2At an energy level, then²F_5/2The particles on the energy level are relaxed to²F_5/2At the lowest Stark sublevel, population inversion is formed, thereby realizing²F_5/2To²F_7/2The stimulated transition generates 1.03 micron near infrared laser, and finally, femtosecond pulse laser output is realized in a mode of mode locking;

(2) the utility model relates to an all-solid-state femtosecond laser of Kerr mode-locked ytterbium-doped gadolinium lanthanum silicate crystal, wherein a Yb GLSO crystal is placed at a Brewster angle, and a pumping light source is focused on the surface of the Yb GLSO crystal to be a focusing light source; when the aperture of the pumping emission hole is smaller than the diameter of a focal spot, the laser in the X-type optical resonant cavity continuously vibrates, so that the conditions of particle beam inversion and the like are met;

(3) the utility model relates to an all-solid-state femtosecond laser of Kerr mode-locked ytterbium-doped gadolinium lanthanum silicate crystal, a concave mirror II reflects femtosecond laser penetrating in a Yb GLSO crystal to SF6 triple prisms arranged in pairs so as to compensate dispersion in a cavity;

(4) the utility model discloses an all-solid-state femtosecond laser of Kerr mode-locked ytterbium-doped gadolinium lanthanum silicate crystal, which adjusts parameters such as the size, the curvature radius of a GLSO crystal, the transmittance of a laser output coupling mirror and the like, thereby controlling the efficiency of outputting femtosecond laser and the pulse width of the femtosecond laser;

(5) the utility model discloses an all solid-state femtosecond laser of ytterbium-doped gadolinium lanthanum silicate crystal is locked to Kerr, GLSO crystal is with gadolinium lanthanum silicate as matrix, and have the femtosecond laser crystal of monoclinic symmetrical structure, compare with gadolinium silicate crystal, because lanthanum ion's introduction in gadolinium lanthanum silicate crystal, has caused bigger system disorder nature, the spectral heterogeneity broadening that causes by system disorder nature can make the emission spectral bandwidth further widen, therefore gadolinium lanthanum silicate has widewell emission spectral bandwidth than gadolinium silicate crystal, be expected to realize shorter pulse laser output.

Drawings

Fig. 1 is a schematic diagram of the structure of the working state of the femtosecond laser of the utility model;

FIG. 2 is a photograph of a crystal of GLSO according to the present invention;

FIG. 3 shows that the present invention is doped with 5 at% Yb³⁺Absorption spectrum of the Yb of the GLSO crystal;

FIG. 4 shows the Yb of the utility model³⁺Energy level transition scheme in Yb: GLSO crystal;

FIG. 5 shows Yb of the present invention³⁺In Yb GLSO crystals²F_5/2→²F_7/2Energy level transition fluorescence decay lifetime graph.

In the figure: 1-pumping; 2-a fiber optic coupler; 3-a focusing lens; a 4-X type optical resonant cavity; 5-Yb is GLSO crystal; 6-SF6 triangular prism; 11-a pump light source; 31-a focused light source; 41-concave mirror I; 42-concave mirror II; 43-a plane mirror; 44-laser output coupling mirror; 51-end face; 52-lateral surface.

Detailed Description

For a further understanding of the present invention, reference will be made to the following detailed description taken in conjunction with the accompanying drawings.

Example 1

The all-solid-state femtosecond laser of the Kerr mode-locked ytterbium-doped gadolinium lanthanum silicate crystal of the embodiment, as shown in fig. 1, includes a pump 1, and a pump light source 11 horizontally output by the pump 1 is emitted to a focusing lens 3 through a fiber coupler 2; the pump light source 11 is focused into a focusing light source 31 through a focusing lens 3 and is emitted to the concave mirror II42 through the Yb GLSO crystal 5, and the concave mirror II42 reflects the femtosecond laser transmitted in the Yb GLSO crystal 5 to the SF6 triple prism 6 for compensating dispersion in the cavity; the femtosecond laser penetrates through the SF6 triple prisms 6 arranged in pairs and then penetrates through the laser output coupling mirror 44 to realize laser output; as shown in fig. 3, the Yb: GLSO crystal 5 has a strong absorption effect in the range of 900-; as shown in FIG. 4, the Yb: GLSO crystal effectively absorbs the energy of the pumping light source and then passes through²F_7/2→²F_5/2Transition of energy level, Yb³⁺Pumping particles of ground state to²F_5/2At an energy level, then²F_5/2The particles on the energy level are relaxed to²F_5/2At the lowest Stark sublevel, population inversion is formed, thereby realizing²F_5/2To²F_7/2The stimulated transition generates 1.03 micron near infrared laser, and femtosecond pulse laser output is realized in a mode of mode locking; the right side of the Yb: GLSO crystal 5 corresponding to the position of the concave mirror II42 is also provided with a concave mirror I41, the surfaces of the concave mirror I41 and the concave mirror II42 are both coated with an antireflection film of 800-1000 nm and a high-reflection film of 1000-1200 nm, laser input into the Yb: GLSO crystal 5 forms an X-type optical resonant cavity 4 through the concave mirror I41 and the concave mirror II42, and the laser oscillated in the X-type optical resonant cavity 4 is reflected by the concave mirror II42 after the conditions of particle beam inversion and the like are met; the laser reflected by the concave mirror I41 reflects back through the plane reflecting mirror 43, the surface of the plane reflecting mirror 43 is coated with a high reflection film of 1000-1200 nm so as to effectively reflect back the laser, and when the aperture of the emission hole of the pump 1 is smaller than the diameter of a focal spot, the laser in the X-shaped optical resonant cavity 4 continuously vibrates, so that the conditions of particle beam inversion and the like are met. At present, a femtosecond laser mainly uses a mode-locked titanium sapphire laser, but because the absorption peak of a titanium sapphire crystal is positioned in a visible waveband, LD direct pumping cannot be directly adopted, and generally only an argon ion laser (with the wavelength of 515nm) or Nd can be adopted³⁺The green light (532nm) obtained by doping the frequency multiplication of the solid laser is used as a pumping source, so that the structure of the laser is complex, the volume is large, and the maintenance cost is high.

Example 2

The basic structure of the all-solid-state femtosecond laser of the Kerr mode-locked ytterbium-doped lanthanum gadolinium silicate crystal of the embodiment is the same as that of the embodiment 1, and the differences and improvements are as follows: as shown in fig. 1, the Yb: GLSO crystal 5 is wrapped with indium foil in advance and fixed on a red copper water-cooled heat sink, the temperature of the water-cooled heat sink is stabilized at about 16 ℃ by adopting an active control mode, and then the Yb: GLSO crystal 5 is placed in a femtosecond laser at a brewster angle to reduce adverse effects of waste heat on laser oscillation; the Yb GLSO crystal 5 comprises a left end surface and a right end surface 51 and a peripheral side surface 52, as shown in figure 2, the left end surface and the right end surface 51 of the Yb GLSO crystal 5 are polished to have high surface smoothness, and good parallelism between the two end surfaces 51 is kept; the pump light source 11 focuses on the end face of the right side of the Yb GLSO crystal 5 to form a focusing light source 31, the focusing light source 31 enters from the end face of the right side of the Yb GLSO crystal 5, penetrates through the Yb GLSO crystal 5 and then penetrates out from the end face of the left side of the Yb GLSO crystal 5; the focal spot diameter of the focusing light source 31 focused on the end face 51 of the Yb GLSO crystal 5 is about 20 μm, the aperture of the emission hole of the pump 1 is 22 μm and is larger than the focal spot diameter, so that the pumping light source 11 can be completely absorbed by the Yb GLSO crystal 5 to realize mode locking;

in this embodiment, the adjustment of parameters such as the size, the curvature radius, and the transmittance of the laser output coupling mirror 44 of the Yb: GLSO crystal 5 affects the efficiency of outputting the femtosecond laser and the pulse width of the femtosecond laser, and the size of the Yb: GLSO crystal 5 is: the length of the end face 51 is 2-8 mm, the length is 2-6 mm, the curvature radius of the concave mirror I41 and the concave mirror II42 is 70-200 mm, and the transmittance of the laser output coupling mirror 44 is 0.2% -1%.

Example 3

The basic structure of the all-solid-state femtosecond laser of the Kerr mode-locked ytterbium-doped lanthanum gadolinium silicate crystal of the embodiment is the same as that of the embodiment 2, and the differences and improvements are as follows: as shown in fig. 1, the laser reflected by the concave mirror i 41 reflects back through the plane mirror 43, the surface of the plane mirror 43 is coated with a high reflective film of 1000-1200 nm to effectively reflect back, and when the aperture of the emission hole of the pump 1 is smaller than the diameter of the focal spot, the laser in the X-shaped optical resonant cavity 4 continuously vibrates, so as to satisfy the conditions of particle beam inversion and the like.

Example 4

The basic structure of the all-solid-state femtosecond laser of the Kerr mode-locked ytterbium-doped lanthanum gadolinium silicate crystal of the embodiment is the same as that of the embodiment 3, and the differences and improvements are as follows: as shown in FIG. 2, the Yb GLSO crystal 5 is a femtosecond laser crystal having a monoclinic symmetric structure and taking gadolinium lanthanum silicate as a matrix; the chemical formula of the Yb/GLSO crystal 5 is Yb³⁺:(GdLa)₂SiO₅Molecular formula Yb_xGd_2-x-yLa_ySiO₅Wherein 0 is<x<1，0<y<GLSO, Yb, gadolinium silicate, in contrast to gadolinium silicate crystalsDue to the introduction of lanthanum ions in the lanthanum crystal, greater system disorder is caused, and the spectral bandwidth of emission spectrum can be further widened due to the spectral non-uniformity broadening caused by the system disorder, so that the gadolinium lanthanum silicate has a wider emission spectral bandwidth than the gadolinium silicate crystal, and is expected to realize shorter pulse laser output; as shown in FIG. 5, Yb³⁺In GLSO crystals²F_5/2→²F_7/2Energy level transition fluorescence decay lifetime graph: it can be seen that the fluorescence decay curve shows the single exponential decay trend, and the Yb is obtained by adopting single exponential fitting³⁺In GLSO crystals²F_5/2→²F_7/2The energy level lifetime is 2.44ms and is longer than Yb³⁺In YAG crystal²F_5/2→²F_7/2Energy level lifetime (1.11 ms); the longer fluorescence lifetime and the wide emission bandwidth both indicate that the Yb: GLSO crystal is very favorable for realizing femtosecond laser output by adopting semiconductor laser pumping, and the Yb: GLSO crystal is expected to realize pulse laser output with shorter energy than femtosecond laser pulse realized by Yb: YAG crystal.

The present invention and its embodiments have been described above schematically, and the description is not limited thereto, and what is shown in the drawings is only one of the embodiments of the present invention, and the actual structure is not limited thereto. Therefore, if the person skilled in the art receives the teaching of the present invention, without departing from the inventive spirit of the present invention, the person skilled in the art should also design the similar structural modes and embodiments without creativity to the technical solution, and all shall fall within the protection scope of the present invention.

Claims

1. A Kerr mode-locked ytterbium-doped gadolinium lanthanum silicate crystal all-solid-state femtosecond laser is characterized in that: the femtosecond laser is used for laser output of Yb GLSO crystal (5), the femtosecond laser comprises a pump (1), a pump light source (11) horizontally output by the pump (1) is emitted to a focusing lens (3) through a fiber coupler (2), and the central wavelength of the pump light source (11) is 940nm or 970 nm; the pump light source (11) is focused into a focusing light source (31) through a focusing lens (3), and is emitted to the concave mirror II (42) through the Yb GLSO crystal (5), the concave mirror II (42) reflects laser to the SF6 triple prism (6), and a laser output coupling mirror (44) is arranged behind the SF6 triple prism (6).

2. The all-solid-state femtosecond laser of the Kerr mode-locked ytterbium-doped lanthanum gadolinium silicate crystal according to claim 1, characterized in that: the Yb/GLSO crystal (5) comprises a left end surface and a right end surface (51) and a peripheral side surface (52), the Yb/GLSO crystal (5) is placed at a Brewster angle, and the pump light source (11) is focused on the right end surface of the Yb/GLSO crystal (5).

3. The all-solid-state femtosecond laser of the Kerr mode-locked ytterbium-doped lanthanum gadolinium silicate crystal according to claim 2, characterized in that: a concave mirror I (41) is further arranged at the position, corresponding to the concave mirror II (42), on the right side of the Yb/GLSO crystal (5), and laser input into the Yb/GLSO crystal (5) forms an X-type optical resonant cavity (4) through the concave mirror I (41) and the concave mirror II (42); the surfaces of the concave mirror I (41) and the concave mirror II (42) are both plated with 800-1000 nm of antireflection film and 1000-1200 nm of high-reflection film.

4. The all-solid-state femtosecond laser of the Kerr mode-locked ytterbium-doped lanthanum gadolinium silicate crystal according to claim 3, characterized in that: the laser reflected by the concave mirror I (41) reflects the laser back through the plane reflecting mirror (43), and the surface of the plane reflecting mirror (43) is plated with a high-reflection film of 1000-1200 nm.

5. The all-solid-state femtosecond laser of the Kerr mode-locked ytterbium-doped lanthanum gadolinium silicate crystal according to claim 4, characterized in that: the curvature radius of the concave mirror I (41) and the concave mirror II (42) is 70-200 mm.

6. The all-solid-state femtosecond laser of Kerr mode-locked ytterbium-doped lanthanum gadolinium silicate crystal according to claim 5, characterized in that: the SF6 triple prisms (6) are arranged in pairs between the concave mirror II (42) and the laser output coupling mirror (44).

7. The all-solid-state femtosecond laser of the Kerr mode-locked ytterbium-doped lanthanum gadolinium silicate crystal according to claim 6, characterized in that: the transmittance of the laser output coupling mirror (44) is 0.2% -1%.

8. The all-solid-state femtosecond laser of the Kerr mode-locked ytterbium-doped lanthanum gadolinium silicate crystal according to claim 7, characterized in that: the Yb/GLSO crystal (5) is a femtosecond laser crystal which takes gadolinium lanthanum silicate as a matrix and has a monoclinic symmetrical structure; the chemical formula of the Yb/GLSO crystal (5) is Yb³⁺:(GdLa)₂SiO₅Molecular formula Yb_xGd_2-x-yLa_ySiO₅Wherein 0 is<x<1，0<y<1, abbreviated as Yb: GLSO.