CN108988115B - A Novel Same Threshold Equivalent Dual Band Mid-Infrared Pulse Laser and Laser Output Method - Google Patents

Abstract

The invention discloses a novel dual-band mid-infrared pulse laser with the same threshold value and a laser output method, and relates to the technical field of mid-near-infrared lasers. The invention includes a 1150 nm LD pump source and a first dichroic mirror arranged in sequence along a horizontal direction. , a second dichroic mirror, a first focusing lens, a double-clad holmium-doped fluoride gain fiber, a first collimating mirror and a gold-coated mirror, and a 1950nm LD pump source disposed above the first dichroic mirror, the first A second focusing lens, an antimonene two-dimensional saturable absorbing material and a second collimating mirror are sequentially arranged between the collimating mirror and the gold-plated reflecting mirror along the horizontal direction. The output of dual-band CW laser, and by adjusting the power ratio of the 1150nm LD pump source and the 1950nm LD pump source, can achieve synchronous equal-efficiency output of ~3μm and ~2.1μm dual-wavelength pulsed lasers, which can be widely used in multi-materials Processing, medical surgery and other fields.

Description

A Novel Same Threshold Equivalent Dual Band Mid-Infrared Pulse Laser and Laser Output Method

technical field

The invention relates to the technical field of mid-near-infrared lasers, and more particularly to a novel mid-infrared pulsed laser with the same threshold and equivalent dual-band and a laser output method.

Background technique

With the continuous development of fiber laser technology, mid-infrared pulsed fiber laser has gradually attracted the attention of many scholars at home and abroad. Its potential applications mainly include military defense, laser minimally invasive surgery, mid-infrared spectroscopy, long-wave mid-infrared pump source, etc. . Due to the continuous maturity of commercial products of high-power semiconductor lasers, diode-pumped erbium- and holmium-doped fluoride fiber lasers are outstanding for achieving high-energy, high-peak-power mid-infrared laser pulses. Generally speaking, there are two ways to realize this pulsed laser chain, namely Q-switching and mode-locking. Among them, the mode-locked fiber laser can realize the laser pulse output of ultra-short and high peak power. At present, the passive mode-locked fiber laser A pulsed laser with femtosecond peak power up to 37kW has been achieved in the ~3 micron waveband; however, Q-switched fiber lasers can effectively achieve higher-energy pulsed laser output. In the past few decades, a large number of The experimentally produced ~3 micron Q-switched fiber laser mainly adopts active Q-switching methods (such as: acousto-optic Q-switching, electro-optical Q-switching and mechanical Q-switching) and passive Q-switching (such as: semiconductor saturable absorber mirrors, transmission type metal-doped crystals) , graphene, topological insulators and new two-dimensional materials such as black phosphorus), compared with solid-state active Q-switched fiber lasers, passive Q-switched fiber lasers have low cost, simple and compact structure, and more importantly, no additional additional The electric drive system to achieve Q-switching.

At present, the rise of new two-dimensional materials mainly focuses on graphene, topological insulators and transmissive metal dichalcogenides, which are expected to become a new type of electro-optical modulation devices due to their excellent physical and chemical properties. In 2004, two-dimensional graphene materials were first discovered, and in 2009, they were used to realize erbium-doped fiber pulsed lasers in the ~1.55-micron waveband; in 2013, Wei Chen et al. The output of erbium-doped fluoride Q-switched pulsed lasers is not very suitable for short-pulse Q-switched lasers because of the extremely low absorption efficiency due to the low modulation depth of this material. Since then, topological insulators and transmissive metal dichalcogenides have been used to generate ~3 μm erbium/holmium fluoride fiber pulsed lasers. Although topological insulators can have a large modulation depth in the broadband range, it is more complex It is difficult to combine the two different components in the preparation process of the broadband transmission type; in addition, the broadband transmission type metal dichalcogenide can make the energy level suitable for the mid-infrared band due to the introduction of some defects inside its material, but its manufacturing process is also relatively complicated and cumbersome. .

In recent years, black phosphorus has attracted much attention due to its unique direct bandgap layer, which is composed of group V elements and has a tunable bandgap in the range of ~0.3eV to ~2eV, which makes it very suitable for near-infrared Even on mid-infrared photoelectric switches, but during the experiment, black phosphorus is easily oxidized in the surrounding environment, causing its performance to deteriorate and further increase its thermal effect reaction with water and oxygen in the air. Compared with the previous two-dimensional materials, antimonene, as a new type of two-dimensional material, has excellent properties, such as: higher stability, greater carrier carrying capacity, excellent thermal conductivity, strain-induced band It is precisely because this material has broadband saturable absorption characteristics, and the pulse energy in the ~3 micron band can be effectively absorbed in the superficial soft tissue, which is very suitable for medical tissue resection without thermal damage. The ~2.1 micron pulsed laser can play a good role in coagulation in laser surgery; in addition, the ~3 micron pulse and ~2.1 micron pulse equivalent to the threshold value also play a very important role in multi-material processing. Therefore, combined with A new type of antimonene two-dimensional material to achieve equivalently stable dual-band (~3 μm and ~2.1 μm) mid-infrared pulsed laser output at the same threshold is a new technical means. This kind of dual-band mid-infrared pulsed laser has many practical applications. play a significant role.

As shown in Figure 3, it is a structural diagram of an erbium-doped ZBLAN fiber laser based on the Q-switching of two-dimensional nanomaterial graphene, which adopts passive Q-switching to realize the output of laser pulses in the ~3 micron waveband. Among them, the 976nm pump laser The diode is used as the pump source, the pump light is coupled into the erbium-doped ZBLAN gain fiber through the collimating lens, the dichroic mirror and the focusing lens, and then the graphene fiber mirror is directly connected to the tail of the gain fiber. The dichroic mirror near the 976nm pump laser diode is derived and the output pulsed laser is filtered for detection. Graphene fiber mirror is to deposit graphene on the fiber mirror as an effective saturable absorption device to realize the formation of intracavity laser pulses. The filter is used to filter out the residual pump light in the output laser. By changing the length of the gain fiber and the The power of the pump light source can be used to achieve ~3 micron laser pulse output in different states, but this laser has the following disadvantages:

1. Since the laser uses two-dimensional nanomaterial graphene as a saturable absorber to achieve passive Q-switched pulse output, the modulation depth of graphene material is low, resulting in a low absorption efficiency of pump light, so it cannot be used. Effectively generate stable short pulse Q-switched laser;

2. The graphene is deposited on the fiber mirror, which makes the experimental operation more difficult. At the same time, the graphene fiber mirror is directly connected to the tail of the gain fiber, which improves the accuracy of the experimental operation, which is not easy to operate, and the residual pumping When the light energy is concentrated on the material, it is very easy to damage the material and greatly reduce the laser conversion efficiency of ~3 microns;

3. The laser can only generate ~3 micron single-wavelength laser pulses, and cannot acquire ~2.1 micron lasers at the same time, so the applicability is narrow.

As shown in Figure 4, it is a structural diagram of an erbium-doped ZBLAN fiber pulsed laser based on two-dimensional black phosphorus Q-switching. It uses a 976nm semiconductor laser as a laser pump source to pump an erbium-doped ZBLAN gain fiber to achieve ~3 micron passive modulation. Q pulsed laser output, in which the pump laser diode is coupled into the erbium-doped gain fiber through the dichroic mirror F2 after passing through the collimating focusing lens F1, and the light from the other end of the gain fiber exits to the two total reflection mirrors M1 and M2 for the optical path. adjusted, and finally injected into the gold mirror coated with two-dimensional material black phosphorus, and the modulation of the pulsed laser was realized; the gold mirror coated with two-dimensional material black phosphorus was prepared by the liquid phase exfoliation method, which acts as a reflection type saturable absorption mirror, the left end face of the erbium-doped gain fiber and the gold mirror coated with two-dimensional material black phosphorus are used as the resonator of the laser, and the dichroic mirror close to the 976nm pump source is used to guide the laser output of ~3 microns. Change the power of the 976nm pump source to obtain the waveform of the output pulse in different states and the corresponding power of the pulse, but this laser has the following shortcomings:

1. Since the laser is based on the two-dimensional material black phosphorus as a saturable absorber to achieve passive Q-switched pulse output, black phosphorus is prepared by liquid phase exfoliation and deposited on the gold mirror. Oxidation causes its performance to attenuate, and further increases the thermal effect reaction with water and oxygen in the air, thus reducing its modulation ability to the system and making the absorption efficiency low, which is not conducive to the stable formation of Q-switched pulses;

2. The two-dimensional material black phosphorus is deposited on the surface of the gold mirror, which is easy to damage the gold mirror and is not conducive to the reuse of the gold mirror, and the preparation cost is high, making the experimental equipment expensive;

3. The laser output wavelength of the laser is single, which is no longer applicable to some applications requiring multi-wavelength laser output, which limits the application potential of the laser.

Since most of the current experiments are based on new two-dimensional materials to achieve passive Q-switched pulsed mid-infrared lasers, the wavelengths are mainly ~3 microns and ~3.5 microns, lacking the synchronous threshold output of ~3 microns and ~2.1 microns dual-wavelength CW lasers, and the commonly used Two-dimensional materials mainly include graphene, topological insulators, and black phosphorus. However, due to the different physical and chemical properties of these two-dimensional materials, long-term stable and broadband operation of Q-switched laser pulses cannot be achieved.

SUMMARY OF THE INVENTION

The purpose of the present invention is: in order to solve the problem that the wavelengths of the existing passive Q-switched pulse mid-infrared lasers based on new two-dimensional materials are mainly ~3 microns and ~3.5 microns, and lack of synchronization of ~3 microns and ~2.1 microns dual-wavelength continuous lasers To solve the problem of threshold output, the present invention provides a novel dual-band mid-infrared pulse laser with the same threshold equivalent and a laser output method.

The present invention specifically adopts the following technical solutions in order to achieve the above object:

A new type of equivalent dual-band mid-infrared pulsed laser with the same threshold value, including a 1150nm LD pump source, a first dichroic mirror, a second dichroic mirror, a first focusing lens, and a double-clad holmium-doped fluoride gain The optical fiber, the first collimating mirror and the gold-plated reflecting mirror are characterized in that: it further comprises a 1950 nm LD pump source arranged above the first dichroic mirror, and the first dichroic mirror and the second dichroic mirror are both arranged obliquely,

The 1150nm LD pump source is used to generate the CW pump laser A; the 1950nm LD pump source is used to generate the CW pump laser B; High reflectivity, used to combine continuous pump laser A and continuous pump laser B; the second dichroic mirror is highly transparent to continuous pump laser A and continuous pump laser B, and is suitable for ~3 micron and ~2.1 micron lasers High reflection, used to guide the generated ~3 micron and ~2.1 micron lasers to output; the first focusing lens is used to focus the continuous pump laser A and the continuous pump laser B to the double-clad holmium-doped fluoride gain fiber , and for collimating the resulting ~3 micron and ~2.1 micron lasers; double-clad holmium-doped fluoride gain fiber for ~3 micron and ~2.1 micron laser generation; first collimator for ~3 micron and ~2.1 micron lasers The 3-micron and ~2.1-micron lasers are collimated and incident on a gold-coated mirror; the gold-coated mirror is highly reflective to the ~3-micron and ~2.1-micron lasers to provide feedback throughout the laser cavity; the double-clad holmium-fluorine-doped The left end face of the compound gain fiber and the gold-coated mirror form a resonant cavity.

Further, a second focusing lens, an antimonene two-dimensional saturable absorbing material and a second collimating mirror are arranged in sequence along the horizontal direction between the first collimating mirror and the gold-plated reflecting mirror. For focusing the ~3 micron and ~2.1 micron lasers, and lasing on the antimonene two-dimensional saturable absorber material; the antimonene two-dimensional saturable absorber material passively Q-switches the ~3 micron and ~2.1 micron lasers; the first The ~3 micron and ~2.1 micron lasers were again collimated by two collimating mirrors and incident on the gold-coated mirrors.

Further, the antimonene two-dimensional saturable absorbing material is prepared by a liquid phase exfoliation method, and is deposited on a CaF ₂ -based substrate.

Further, the angle between the left end face and the horizontal plane of the double-clad holmium fluoride gain fiber is 0°, and the angle between the right end face and the horizontal plane is an oblique angle of 8°, which is used to prevent parasitic laser oscillation.

Further, the energy level change process in the double-clad holmium-doped fluoride gain fiber is: the continuous pumping laser A pumps part of the ground state particles on the ⁵ I _8/2 energy level to the ⁵ I _6/2 energy level. , realize the ground state absorption process A ⁵ I _8/2 → ⁵ I _6/2 , accumulate ground state particles for the ⁵ I _6/2 energy level, and realize the particles between the ⁵ I _6/2 energy level and the ⁵ I _7/2 energy level Number inversion, so that the particle transition from the ⁵ I _6/2 energy level to the ⁵ I _7/2 energy level produces a ~3 micron laser;

The continuous pumping laser B pumps part of the ground state particles on the ⁵ I _8/2 energy level to the ⁵ I _7/2 energy level, and realizes the ground state absorption process B ⁵ I _8/2 → ⁵ I _7/2 , which is ⁵ I The _7/2 energy level accumulates ground-state particles, realizing the population inversion between the ⁵ I _7/2 energy level and the ⁵ I _8/2 energy level, so that the particles on the ⁵ I _7/2 energy level transition to ⁵ I _8/2 The energy level produces a ~2.1 micron laser.

The laser output method of a new type of equivalent dual-band mid-infrared pulsed laser with the same threshold includes the following steps:

S1: Turn on the 1150nm LD pump source and the 1950nm LD pump source, the 1150nm LD pump source generates continuous pump laser A, and the 1950nm LD pump source generates continuous pump laser B;

S2: After the continuous pump laser A and the continuous pump laser B are combined by the first dichroic mirror, they are coupled into the double-clad holmium fluoride gain fiber through the second dichroic mirror and the first focusing lens. The continuous pumping laser A in the holmium-doped fluoride gain fiber makes part of the ground state particles radiate from the ⁵ I _6/2 energy level to the ⁵ I _7/2 energy level to generate ~3 μm laser light, and the continuous pumping laser B makes part of the ground state particles radiate from the ⁵ I 7/2 energy level. I _7/2 energy level radiation to ⁵ I _8/2 energy level produces ~2.1 micron laser;

S3: respectively adjust the power of the 1150nm LD pump source and the 1950nm LD pump source to achieve the generation of dual-wavelength CW lasers with the same threshold of ~3 microns and ~2.1 microns;

S4: The generated ~3 micron and ~2.1 micron dual-wavelength CW lasers are collimated by the first collimating mirror, and then irradiated on the gold-coated mirror. The output is collimated by a first focusing lens and reflected by a second dichroic mirror to guide the output.

Further, the second focusing lens, the antimonene two-dimensional saturable absorbing material and the second collimating mirror are placed between the first collimating mirror and the gold-coated mirror, and the antimonene two-dimensional saturable absorbing material is adjusted to focus on the second At the focal length of the lens, adjust the power of the 1150nm LD pump source and the 1950nm LD pump source respectively. When S3 generates dual-wavelength continuous lasers with the same threshold of ~3 microns and ~2.1 microns, a relaxation oscillation process is formed, and then the ~3 microns generated by S4 After being collimated by the first collimating lens, the two-wavelength continuous lasers of ~3 microns and ~2.1 microns are focused and injected into the antimonene two-dimensional saturable absorption material through the second focusing lens. The two-dimensional saturable absorbing material modulates the ~3 micron and ~2.1 micron dual-wavelength continuous lasers, and then modulates and then injects into the gold-coated mirror through the second collimating mirror to achieve a high peak power of ~3 microns with narrowed pulse width. and ~2.1 μm dual wavelength pulsed laser output.

Further, the powers of the pulsed lasers of ~3 microns and ~2.1 microns were measured from behind the second dichroic mirror, and the slope efficiencies were calculated respectively, and the power ratios of the 1150 nm LD pump source and the 1950 nm LD pump source were adjusted to achieve ~ 3 microns and Synchronous equal-efficiency output of ~2.1 micron dual-wavelength pulsed laser.

The beneficial effects of the present invention are as follows:

1. The present invention can realize the dual-wavelength continuous laser of ~3 microns and ~2.1 microns with the same threshold value by using the continuous laser pump source in the 1150nm and 1950nm bands to perform hybrid pumping on the double-clad holmium-doped fluoride gain fiber. It can effectively avoid the laser transition self-termination phenomenon caused by the ~3 micron transition saturation phenomenon. The method of the present invention can achieve high efficiency ~3 micron laser output, and can reduce the problem of high heat generation when the gain fiber is output at a single wavelength.

2. The present invention prepares a new two-dimensional material antimonene by adopting a liquid phase exfoliation method, and deposits it on the surface of a CaF ₂ substrate to make a transmission-type saturable absorption device. The fabrication cost is low, and the operation is simple, which greatly reduces the difficulty of experimental operation. , at the same time simplifying the system, and due to the unique advantages of antimonene, such as high stability, large carrier carrying capacity, excellent thermal conductivity, strain-induced bandgap conversion and broadband absorption, it is conducive to the generation of synchronization ~3 Micron and ~2.1 micron pulsed lasers were output simultaneously.

3. By adjusting the power ratio of the 1150nm and 1950nm pump sources, the present invention is easy to achieve the output power of ~3 microns and ~2.1 microns passively Q-switched pulsed laser output with the same efficiency, and is based on the stability of the new two-dimensional antimonene material. The pulsed laser output by the whole system can work stably for a long time, and the laser of the present invention can be widely used in the fields of multi-material processing, medical surgery and the like.

Description of drawings

Figure 1 is a schematic diagram of the overall structure of the present invention.

Figure 2 is a simplified energy level diagram of a double-clad holmium-doped fluoride gain fiber.

Figure 3 is a structural diagram of an erbium-doped ZBLAN fiber laser based on two-dimensional nanomaterial graphene Q-switching.

Figure 4 is a structural diagram of an erbium-doped ZBLAN fiber pulsed laser based on two-dimensional black phosphorus Q-switching.

Reference numerals: 1. 1150 nm LD pump source; 2, 1950 nm LD pump source; 3, first dichroic mirror; 4, second dichroic mirror; 5, first focusing lens; 6, double-clad holmium-doped fluoride Gain fiber; 7. First collimating mirror; 8. Second focusing lens; 9. Antimonene two-dimensional saturable absorbing material; 10. Second collimating mirror; 11. Gold-coated mirror; 12, ⁵ I _8/2 Energy level; 13, ⁵ I _7/2 energy level; 14, ⁵ I _6/2 energy level; 15, ground state absorption process A; 16, ground state absorption process B; 17, ~3 micron laser; 18, ~2.1 micron laser .

Detailed ways

For those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and the following embodiments.

Example 1

As shown in FIG. 1 , this embodiment provides a novel dual-band mid-infrared pulsed laser with the same threshold value, which includes a 1150 nm LD pump source 1 , a first dichroic mirror 3 , and a second dichroic mirror arranged in sequence along the horizontal direction. 4. The first focusing lens 5, the double-clad holmium-doped fluoride gain fiber 6, the first collimating mirror 7 and the gold-coated mirror 8, also include a 1950nm LD pump source 2 arranged above the first dichroic mirror 3, so The first dichroic mirror 3 and the second dichroic mirror 4 are all inclined and arranged, and the specific inclination angle is determined according to the actual situation. The included angle with the horizontal plane is an 8° oblique angle,

Among them, the 1150nm LD pump source 1 is used to generate the continuous pump laser A; the 1950nm LD pump source 2 is used to generate the continuous pump laser B; the first dichromatic mirror 3 is highly transparent to the continuous pump laser A, and The pump laser B has high reflection and is used to combine the continuous pump laser A and the continuous pump laser B; the second dichroic mirror 4 is highly transparent to the continuous pump laser A and the continuous pump laser B, and is suitable for ~3 microns and The ~2.1 micron laser is highly reflective, used to guide the generated ~3 micron and ~2.1 micron lasers to output; the first focusing lens 5 is used to focus the continuous pump laser A and the continuous pump laser B to the double cladding doping Holmium fluoride gain fiber 6, and for collimating the generated ~3 micron and ~2.1 micron lasers; double-clad holmium fluoride gain fiber 6 for generating ~3 micron and ~2.1 micron lasers; first The collimating mirror 7 is used for collimating the ~3 micron and ~2.1 micron lasers and incident on the gold-coated mirror 11; the gold-coated mirror 11 is highly reflective to the ~3 micron and ~2.1 micron lasers and is used to provide feedback of the laser cavity ; The left end face of the double-clad holmium-doped fluoride gain fiber 6 and the gold-coated mirror surround a resonant cavity.

The laser output method of a new type of equivalent dual-band mid-infrared pulsed laser with the same threshold includes the following steps:

S1: Turn on 1150 nm LD pump source 1 and 1950 nm LD pump source 2, 1150 nm LD pump source 1 generates continuous pump laser A, and 1950 nm LD pump source 2 generates continuous pump laser B;

S2: After the continuous pump laser A and the continuous pump laser B are combined by the first dichroic mirror 3, they are coupled into the double-clad holmium-doped fluoride gain fiber 6 through the second dichroic mirror 4 and the first focusing lens 5, In the double-clad holmium-doped fluoride gain fiber 6, the continuous pump laser A makes the particles on the ⁵ I _6/2 energy level 14 radiate to the ⁵ I _7/2 energy level 13 to generate a ~3 micron laser 17, and the continuous pump laser B makes the particles on the ⁵ I _7/2 energy level 13 radiate to the ⁵ I _8/2 energy level 12 to generate a ~2.1 micron laser 18;

The energy level change process in the double-clad holmium fluoride gain fiber 6 is as follows: the continuous pump laser A pumps part of the ground state particles on the ⁵ I _8/2 energy level 12 to the ⁵ I _6/2 energy level 14 , realize the ground state absorption process A15 ⁵ I _8/2 → ⁵ I _6/2 , accumulate ground state particles for the ⁵ I _6/2 energy level 14, and realize the ⁵ I _6/2 energy level 14 and ⁵ I _7/2 energy level 13 The particle number inversion between ⁵ I _6/2 energy level 14 and ⁵ I _7/2 energy level 13 produces a ~3 micron laser 17;

The continuous pumping laser B pumps part of the ground state particles on the ⁵ I _8/2 energy level 12 to the ⁵ I _7/2 energy level 13, and realizes the ground state absorption process B16 ⁵ I _8/2 → ⁵ I _7/2 , which is The ⁵ I _7/2 energy level 13 accumulates ground-state particles, and the population inversion between the ⁵ I _7/2 energy level 13 and the ⁵ I _8/2 energy level 12 is realized, and the particles on the ⁵ I _7/2 energy level 13 transition. To ⁵ I _8/2 energy level 12 to generate ~2.1 micron laser 18;

S3: Adjust the power of the 1150nm LD pump source 1 and the 1950nm LD pump source 2 respectively to achieve the generation of dual-wavelength CW lasers with the same threshold of ~3 microns and ~2.1 microns, specifically:

Properly adjust the power of 1150nmLD pump source 1 and 1950nmLD pump source 2 so that the power ratios between them satisfy:

The power ratio of 1150nm LD pump source 1 is: 35%<P ₁₁₅₀ /(P ₁₁₅₀ +P ₁₉₅₀ )<50%;

The power ratio of 1950nm LD pump source 2 is: 50%<P ₁₉₅₀ /(P ₁₁₅₀ +P ₁₉₅₀ )<75%;

S4: The generated dual-wavelength continuous lasers of ~3 microns and ~2.1 microns are collimated by the first collimating mirror 7, and then irradiated on the gold-coated mirror 11. After being reflected by the gold-coated mirror 11, the double-clad holmium-doped fluoride is used to gain gain The left end face of the optical fiber 6 is output, and is collimated by the first focusing lens 5 and reflected by the second dichroic mirror 4 to guide the output.

Example 2

This embodiment is further optimized on the basis of Embodiment 1, specifically:

A second focusing lens 8, an antimonene two-dimensional saturable absorbing material 9 and a second collimating mirror 10 are sequentially arranged between the first collimating mirror 7 and the gold-coated mirror 11 along the horizontal direction. The lens 8 is used to focus the ~3 micron and ~2.1 micron lasers, and lasing on the antimonene two-dimensional saturable absorbing material 9; the antimonene two-dimensional saturable Passive Q-switching; the second collimating mirror 10 collimates the ~3 micron and ~2.1 micron lasers again and enters the gold-coated mirror 11, and the antimonene two-dimensional saturable absorbing material is prepared by the liquid phase exfoliation method, and deposited on the CaF ₂ base.

The second focusing lens 8, the antimonene two-dimensional saturable absorbing material 9 and the second collimating mirror 10 are placed between the first collimating mirror 7 and the gold-plated mirror 11, and the antimonene two-dimensional saturable absorbing material 9 is adjusted to At the focal length of the second focusing lens 8, the powers of the 1150 nm LD pump source 1 and the 1950 nm LD pump source 2 are adjusted respectively so that their power ratios meet the conditions in the embodiment, and the same thresholds of ~3 μm and ~2.1 μm are generated at S3 When the dual-wavelength continuous laser is used, a relaxation oscillation process is formed, and then the ~3 microns and ~2.1 microns dual-wavelength continuous lasers generated by S4 are collimated by the first collimating lens 7, and the ~3 microns and ~ The 2.1-micron dual-wavelength CW laser is focused and injected into the antimonene two-dimensional saturable absorbing material 9, and the ~3-micron and ~2.1-micron dual-wavelength CW lasers are modulated by the antimonene two-dimensional saturable absorbing material 9. The collimating mirror 10 is incident on the gold-coated mirror 11. During the relaxation process, due to the difference in signal strength, it will be modulated by the antimonene two-dimensional saturable absorbing material 9. When the laser power is high, this part of the laser can be effectively Through the antimonene two-dimensional saturable absorbing material 9, when the laser power is low, the part of the laser light will be absorbed by the antimonene two-dimensional saturable absorbing material 9, so that the above process is continuously cycled during the laser oscillation process, so that the pulse The places where the laser light intensity is strong keeps getting stronger, and the weaker places are continuously absorbed, finally realizing the output of dual-wavelength pulsed laser of ~3 microns and ~2.1 microns with high peak power with narrowed pulse width.

Example 3

This embodiment is further optimized on the basis of Embodiment 2, specifically:

From the second dichroic mirror 4, the powers of the pulsed lasers of ~3 microns and ~2.1 microns were measured respectively, and the slope efficiencies were calculated respectively, and the power ratios of the 1150 nm LD pump source and the 1950 nm LD pump source were adjusted to meet the conditions in Example 1, The difference between the calculated two-slope efficiencies is made to float below 2%, and the synchronous equal-efficiency output of the dual-wavelength pulsed lasers of ~3 microns and ~2.1 microns is realized.

The above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. The scope of patent protection of the present invention is subject to the claims. Any equivalent structural changes made by using the contents of the description and drawings of the present invention, Similarly, all should be included in the protection scope of the present invention.

Claims (4)

1. The utility model provides an with threshold value equivalent dual band mid infrared pulse laser, includes 1150nmLD pumping source (1), first dichroic mirror (3), second dichroic mirror (4), first focusing lens (5), double-clad holmium-doped fluoride gain optic fibre (6), first collimating mirror (7) and gilt speculum (11) that set up in order along the horizontal direction, its characterized in that: the lighting device also comprises a 1950nmLD pump source (2) arranged above the first dichroic mirror (3), wherein the first dichroic mirror (3) and the second dichroic mirror (4) are obliquely arranged,

wherein the 1150nmLD pump source (1) is used for generating continuous pump laser A; 1950nmLD pump source (2) for generating continuous pump laser B; the first dichroic mirror (3) is highly transparent to the continuous pumping laser A and highly reflective to the continuous pumping laser B, and is used for combining the continuous pumping laser A and the continuous pumping laser B; the second dichroic mirror (4) is highly transparent to the continuous pumping laser A and the continuous pumping laser B, highly reflective to the-3 micron and-2.1 micron lasers, and is used for guiding and outputting the generated-3 micron and-2.1 micron lasers; the first focusing lens (5) is used for focusing the continuous pumping laser A and the continuous pumping laser B into the double-clad holmium-doped fluoride gain fiber (6) and collimating the generated laser with the wavelength of-3 micrometers and-2.1 micrometers; a double-clad holmium-doped fluoride gain fiber (6) is used for generating laser of 3-micron and 2.1-micron; the first collimating mirror (7) is used for collimating the laser light of 3 micrometers and 2.1 micrometers and is incident on the gold-plated reflecting mirror (11); the gold-plated reflecting mirror (11) is highly reflective to the laser light of 3 microns and 2.1 microns and is used for providing feedback of the whole laser cavity; the left end surface of the double-clad holmium-doped fluoride gain fiber (6) and the gold-plated reflector enclose a resonant cavity;

a second focusing lens (8), an antimonene two-dimensional saturable absorption material (9) and a second collimating lens (10) are sequentially arranged between the first collimating mirror (7) and the gold-plated reflecting mirror (11) along the horizontal direction, and the second focusing lens (8) is used for focusing lasers of-3 micrometers and-2.1 micrometers and exciting the lasers to the antimonene two-dimensional saturable absorption material (9); the stibene two-dimensional saturable absorption material (9) passively adjusts Q of the laser of 3 microns and 2.1 microns; the second collimating mirror (10) collimates the laser of 3 microns and 2.1 microns again and then irradiates the laser to the gold-plated reflecting mirror (11);

the stibene two-dimensional saturable absorption material (9) is prepared by a liquid phase stripping method and is deposited on CaF₂A substrate;

and measuring the power of the pulse laser with the wavelength of 3 microns and 2.1 microns from the second dichroic mirror (4), calculating the skew efficiency, adjusting the power ratio of the 1150nmLD pump source (1) to the 1950nmLD pump source (2), and realizing the synchronous equivalent rate output of the pulse laser with the wavelength of 3 microns and 2.1 microns.

2. The same-threshold equivalent dual-band mid-ir pulsed laser according to claim 1, characterized in that: the left end face of the double-clad holmium-doped fluoride gain fiber (6) forms an angle of 0 degree with the horizontal plane, and the right end face of the double-clad holmium-doped fluoride gain fiber forms an oblique angle of 8 degrees with the horizontal plane.

3. The same-threshold equivalent dual-band mid-ir pulsed laser according to claim 1, characterized in that: the energy level change process in the double-clad holmium-doped fluoride gain fiber (6) is as follows: continuously pumped laser A will⁵I_8/2Pumping part of the ground state particles at energy level (12) to⁵I_6/2At energy level (14), effecting a ground state absorption process A (15)⁵I_8/2→⁵I_6/2Is a⁵I_6/2Energy level (14) accumulates ground state particles to achieve⁵I_6/2Energy level (14) and⁵I_7/2the population between the energy levels (13) is reversed so that⁵I_6/2Transition of particles on energy level (14) to⁵I_7/2The energy level (13) generates a-3 micron laser (17);

continuously pumped laser B will⁵I_8/2Pumping part of the ground state particles at energy level (12) to⁵I_7/2At energy level (13), effecting a ground state absorption process B (16)⁵I_8/2→⁵I_7/2Is a⁵I_7/2Energy level (13) accumulates ground state particles to achieve⁵I_7/2Energy level (13) and⁵I_8/2the population between the energy levels (12) is reversed to⁵I_7/2Transition of particles on energy level (13) to⁵I_8/2The energy level (12) produces a 2.1 micron laser (18).

4. A laser output method of a same-threshold equivalent dual-waveband intermediate infrared pulse laser is characterized by comprising the following steps:

s1: starting 1150nmLD pump source (1) and 1950nmLD pump source (2), wherein the 1150nmLD pump source (1) generates continuous pump laser A, and the 1950nmLD pump source (2) generates continuous pump laser B;

s2: after the continuous pumping laser A and the continuous pumping laser B are combined through the first dichroic mirror (3), the continuous pumping laser A and the continuous pumping laser B are coupled into the double-cladding holmium-doped fluoride gain optical fiber (6) through the second dichroic mirror (4) and the first focusing lens (5), and the continuous pumping laser A in the double-cladding holmium-doped fluoride gain optical fiber (6) enables the continuous pumping laser A to be pumped⁵I_6/2Particles at an energy level (14) are irradiated to⁵I_7/2The energy level (13) generates a-3 micron laser (17) that is continuously pumped by laser B⁵I_7/2Particles at an energy level (13) are irradiated to⁵I_8/2An energy level (12) generates a 2.1 micron laser (18);

s3: the power of the 1150nmLD pump source (1) and the power of the 1950nmLD pump source (2) are respectively adjusted, and the generation of dual-wavelength continuous laser with the same threshold value of 3 microns and 2.1 microns is realized;

s4: the generated continuous laser with double wavelengths of 3 microns and 2.1 microns is collimated by a first collimating mirror (7), then is emitted onto a gold-plated reflecting mirror (11), is reflected by the gold-plated reflecting mirror (11), is output from the left end face of a double-clad holmium-doped fluoride gain optical fiber (6), and is collimated by a first focusing lens (5) and reflected by a second dichroic mirror (4) to be guided to be output;

placing a second focusing lens (8), an antimonene two-dimensional saturable absorption material (9) and a second collimating lens (10) between a first collimating lens (7) and a gold-plated reflecting mirror (11), adjusting the antimonene two-dimensional saturable absorption material (9) at the focal length of the second focusing lens (8), respectively adjusting the power of a 1150nmLD pump source (1) and a 1950nmLD pump source (2), then after collimating the-3 micron and-2.1 micron dual-wavelength continuous laser generated by S4 through the first collimating lens (7), focusing the-3 micron and-2.1 micron dual-wavelength continuous laser through the second focusing lens (8) and injecting into the antimonene two-dimensional saturable absorption material (9), modulating the-3 micron and-2.1 micron dual-wavelength continuous laser through the antimonene two-dimensional saturable absorption material (9), injecting the modulated dual-wavelength continuous laser into the reflecting mirror (11) through the second collimating lens (10), the output of pulse laser with double wavelengths of 3 microns and 2.1 microns with narrow pulse width and high peak power is realized;

and measuring the power of the pulse laser with the wavelength of 3 microns and 2.1 microns from the second dichroic mirror (4), calculating the skew efficiency, adjusting the power ratio of the 1150nmLD pump source (1) to the 1950nmLD pump source (2), and realizing the synchronous equivalent rate output of the pulse laser with the wavelength of 3 microns and 2.1 microns.

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