A transmission electron microscope sample rod with in-situ laser loading

Abstract

The application discloses a transmission electron microscope sample rod loaded with laser in situ, which comprises, from front end to rear end, a sample rod head with a hollow structure, a first lens arranged in front of the front end, a sample loading platform arranged in front of the first lens, a rod body with a hollow structure, a rear end of the rod body coaxially connected with a rear end of the sample rod head, a window sheet arranged at a rear end of the rod body and in sealing connection with the rod body, a second lens arranged at a rear end of the window sheet and forming a double-lens group with the first lens, a five-axis displacement adjustment mechanism comprising a displacement platform base, a five-axis displacement platform and a light shield cover, and an Fc / Pc seat arranged on the five-axis displacement platform and used for connecting a laser source optical fiber, the five-axis displacement platform being used for controlling X / Y / Z direction displacement and pitch / level inclination of a laser focal point. The transmission electron microscope sample rod can reduce the cost of an electron microscope, is simple to operate and supports 0-2200nm waveband laser in-situ regulation and control of sample energy transient change observation.

Description

Technical Field

[0001] This invention relates to the field of transmission electron microscopy, and in particular to a transmission electron microscope sample holder with in-situ laser loading. Background Technology

[0002] The macroscopic properties of materials depend on their microstructure, and transmission electron microscopy (TEM) is a key instrument for characterizing and studying the microstructure of materials. The TEM sample holder is used to support the thin electron microscope sample to be examined and is one of the key components for characterizing the structure and properties of TEM samples.

[0003] With the advancement of transmission electron microscopy (TEM) technology, the demand for in-situ structural and property correlation testing is increasing, making the development of in-situ electron microscopy sample holders a crucial direction. In recent years, in-situ electron microscopy has enabled the characterization and testing of samples under multiple excitation conditions, including liquids, gases, temperature, illumination, electric fields, magnetic fields, and pressure, and even in-situ testing with multi-field coupling. These in-situ electron microscopy techniques provide indispensable analytical tools for studying sample structure and function. However, electron microscopy sample holders capable of providing in-situ loaded high-energy lasers are still in the laboratory testing stage, especially lacking TEM sample holders capable of providing multiple laser types.

[0004] Traditional transmission electron microscopy (TEM) records the steady-state distribution of electron waves penetrating a sample, making it difficult to obtain information on continuous or instantaneous energy changes in the microstructure of materials. Laser energy injection, combined with TEM, can record electron wave information penetrating the sample, enabling high spatiotemporal resolution microscopic imaging. In contrast, the development and modification of ultrafast TEM can record transient energy distribution and changes in samples, achieving high spatiotemporal resolution microscopic imaging. However, its development and modification are not only large-scale and expensive but also inconvenient to operate, hindering more electron microscopy laboratories and research groups in China from developing in-situ laser applications.

[0005] In the field of structural dynamics, using laser energy injection to observe and record continuous or transient changes in sample energy is a very important physical process. The analysis of this process is of great significance for future high spatiotemporal resolution studies of structural dynamics.

[0006] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0007] The purpose of this invention is to provide a transmission electron microscope sample holder with in-situ laser loading, thereby enabling in-situ observation of the evolution mechanism of the sample under the action of high-energy laser at the Wiener scale.

[0008] To achieve the above objectives, the present invention provides a transmission electron microscope sample rod for in-situ laser loading, comprising, from front to rear: a sample rod head, which is a hollow structure, with a first lens at the front end and a sample carrier stage at the front of the first lens; a rod body, which is also a hollow structure, with its front end coaxially connected to the rear end of the sample rod head, and a window at the rear end of the rod body sealed to the rod body, and a second lens at the rear end of the window, forming a double lens group with the first lens; a five-axis displacement adjustment mechanism, comprising a displacement stage base, a five-axis displacement stage, and a light shield, wherein the displacement stage base is located at the rear end of the rod body and connected to the rod body, the five-axis displacement stage is mounted on the displacement stage base, and the light shield covers the displacement stage base and the five-axis displacement stage; and an Fc / Pc seat, which is mounted on the five-axis displacement stage, the Fc / Pc seat being used to connect the laser source fiber and located behind the rod body; wherein the five-axis displacement stage is used to control the laser focus displacement in the X / Y / Z directions and the pitch / horizontal tilt angle.

[0009] Preferably, in the above technical solution, the five-axis displacement stage includes an X-axis displacement stage, a Y / Z-axis displacement stage, and an L-shaped tilt stage. The X-axis displacement stage is movable in the X-axis direction and is mounted on the displacement stage base. The Y / Z-axis displacement stages are stacked on the X-axis displacement stage. The Fc / Pc seat is movable in the Y and Z-axis directions and is mounted on the Y / Z-axis displacement stage. The L-shaped tilt stage is fixedly mounted on the X-axis displacement stage and is movably connected to the Y / Z-axis displacement stage. The pitch / horizontal tilt angle of the laser focus is adjusted by adjusting the pitch / horizontal tilt angle of the Y / Z-axis displacement stage.

[0010] Preferably, in the above technical solution, the pitch / tilt angle of the Y / Z axis displacement stage is within the range of ±15°.

[0011] Preferably, in the above technical solution, the L-shaped tilting table includes a horizontal part and a vertical part. The intersection of the horizontal part and the vertical part is ball-connected to the Y / Z axis displacement table through a metal ball. The horizontal part is connected to the Y / Z axis displacement table through a first screw and a first spring. The first screw works in conjunction with the metal ball to adjust the rotation of the Y / Z axis displacement table around the Z-axis, thereby driving the pitch adjustment of the Fc / Pc seat around the Z-axis.

[0012] The vertical part is connected to the Y / Z axis displacement stage via a second screw and a second spring. The second screw works with a metal ball to adjust the rotation of the Y / Z axis displacement stage around the Y axis, thereby driving the pitch adjustment of the Fc / Pc seat around the Y axis.

[0013] Preferably, in the above technical solution, the end face of the fiber optic connector of the Fc / Pc holder has an angle.

[0014] Preferably, in the above technical solution, the tip angle of the Fc / Pc holder is 8°, and the reflected light deviates from the original path by ≥15°.

[0015] Preferably, in the above technical solution, the sample carrier platform has a semi-circular groove in the middle for placing objects, and the diameter of the semi-circular hole is ≤100μm.

[0016] Preferably, in the above technical solution, the distance between the first lens and the second lens is 24.17 mm; the first lens has an EFL of 6.2 mm / BEL of 4.1 mm and an NIR coating of 600-1050 nm; the second lens has an EFL of 18 mm / BEL of 17.07 mm and no coating of 350-2200 nm.

[0017] Preferably, in the above technical solution, the NIR coating of the window sheet is 600-1100nm, and the single-sided reflectivity is <0.5%.

[0018] Preferably, in the above technical solution, the window is located at the rear end of the rod and is vacuum-sealed with a sealing ring via a vacuum flange.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] (1) The transmission electron microscope sample rod with in-situ laser loading of the present invention uses laser as light source and adopts a five-axis displacement adjustment mechanism to achieve precise positioning (accuracy ≤1μm) and tilt angle adjustment (±0.1°) of laser spot at any position of the carrier grid. This solves the problem that the traditional three-axis displacement stage cannot accurately control the focus tilt angle, and significantly improves experimental efficiency and data accuracy.

[0021] (2) A fixed double lens group is used to ensure that the optical path does not need to be adjusted. Combined with NIR coated window, the optical power loss is minimized and the stability of laser spot intensity is guaranteed (fluctuation ≤ ±2%), avoiding the experimental errors caused by repeated adjustment of the optical path in the existing technology. Optical path stability and power fidelity are achieved.

[0022] (3) The combination of window plate, vacuum flange, and NBR sealing ring achieves ultra-high vacuum sealing (leakage rate ≤1×10). -9 (Pa·m³ / s), while the tilted pigtail design of the Fc / Pc socket (end face tilt angle 8°) causes the reflected light to deviate from the original path by ≥15°, completely eliminating reflection noise caused by uneven fiber refractive index and solving the technical bottleneck of unstable laser spot. This achieves vacuum sealing and noise suppression.

[0023] (4) The Fc / Pc mount supports quick replacement of lasers with different wavelengths (0-2200nm), power and operating modes. Combined with the cuboid light shield to block ambient light interference, the equipment can adapt to diverse in-situ testing needs (such as observation of continuous / instantaneous energy changes), greatly reducing the purchase cost of ultrafast electron microscopes (cost is only 10% of that of ultrafast electron microscopes) and the complexity of operation; multi-scenario compatibility and ease of operation.

[0024] (5) The cuboid design of the light shield integrating a five-axis displacement stage and base significantly reduces the center of gravity shift during adjustment (offset ≤ 0.1 μm), ensuring the accuracy of sample position; the copper wire welding process between the sample rod and the rod head enhances the overall rigidity and avoids the influence of mechanical vibration on observation. This achieves structural optimization and anti-interference capability. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the transmission electron microscope sample rod with in-situ laser loading according to the present invention;

[0026] Figure 2 This is an isometric side view of a transmission electron microscope sample rod with in-situ laser loading according to the present invention;

[0027] Figure 3 This is a schematic diagram of the five-axis displacement adjustment mechanism in the transmission electron microscope sample rod with in-situ laser loading according to the present invention.

[0028] Figure 4 This is a schematic diagram of the front end of the sample rod head in the transmission electron microscope sample rod with in-situ loaded laser according to the present invention;

[0029] Figure 5 This is a schematic diagram of the five-axis displacement adjustment mechanism in the transmission electron microscope sample rod with in-situ laser loading according to the present invention.

[0030] Figure 6 This is a schematic diagram of the side of the five-axis displacement adjustment mechanism in the transmission electron microscope sample rod with in-situ laser loading according to the present invention. Detailed Implementation

[0031] The following detailed description of specific embodiments is provided in conjunction with the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0032] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0033] Unless otherwise specified, all raw materials and reagents used in the examples are commercially available.

[0034] like Figures 1 to 6 As shown, a transmission electron microscope sample holder for in-situ laser loading according to a specific embodiment of the present invention includes, from front to rear, a sample holder head 1, a holder body 2, a five-axis displacement adjustment mechanism 3, and an Fc / Pc seat 4, wherein the Fc / Pc seat 4 is connected to the laser source. The specific structure is as follows:

[0035] The sample rod head 1 is a hollow structure. A first lens 12 is located at the front end of the rod body 11. The first lens 12 is a focusing lens with an EFL of 6.2 mm and a BEL of 4.1 mm, coated with NIR (600-1050 nm reflectivity <0.5%). A sample stage 13 is located in front of the first lens 11. The sample stage 13 has a semi-circular groove in the center for placing samples; the aperture of this semi-circular groove is ≤100 μm. It is compatible with standard transmission electron microscope samples.

[0036] The rear end of the sample rod 1 is connected to the rod body 2. The sample rod 1 and rod body 2 are welded together with copper wire to enhance rigidity, and are coaxially connected. The rear end of the rod body 2 has a window 21 with a 600-1100nm NIR coating and a single-sided reflectivity of <0.5%. This preserves the laser power entering the sample rod, ensuring the power of the laser spot and reducing errors. The window 21 is located at the rear end of the rod body 2 and is vacuum-sealed with an NBR sealing ring via a vacuum flange. During testing, the front end of the sample rod 1 is placed inside the detector. A vacuum is drawn inside the detector, and the gas inside the cavity between the sample rod 1 and rod body 2 is extracted. Because the end of the rod body 2 has a window and a sealed connection, gas can only exit and not enter, maintaining a vacuum seal in the cavity between the sample rod 1 and rod body 2. Vacuum seal (leakage rate ≤ This ensures the vacuum level of the electron microscope tube. The sample holder is located inside a sealed chamber, isolated from the external environment, thus guaranteeing the vacuum level of the transmission electron microscope tube and the goniometer stage.

[0037] A second lens 22 is provided at the rear end of the window 21. The second lens 22 is installed at the end of the rod 2 and forms a double lens group with the first lens 12. The second lens 22 is a collimating lens with EFL=18mm / BEL=17.07mm, no coating (compatible with the entire 350-2200nm wavelength range), and is fixed to the end of the rod 2 to collimate the diverging laser into a parallel beam. The distance between the first lens 12 and the second lens 22 is 24.17mm, ensuring that the spot diameter is ≤5μm. The first lens 12 and the second lens 22 are fixed to ensure the stability of the optical path. In the initial stage, the laser source converges precisely at the center of the carrier mesh after passing through these two lenses.

[0038] The five-axis displacement adjustment mechanism 3 includes a displacement stage base 31, a five-axis displacement stage 32, and a light shield 33. The displacement stage base 31 is located at the rear end of the rod 2 and connected to the rod 2. The five-axis displacement stage 32 is mounted on the displacement stage base 31, and the light shield 33 covers the displacement stage base 31 and the five-axis displacement stage 32. The light shield 33 can block light from entering the transmission electron microscope in the laboratory, avoiding noise interference with imaging and reducing errors.

[0039] The Fc / Pc connector 4 is mounted on the five-axis displacement stage 32 and is secured with screws. The connector is made of metal, which helps protect it from damage during repeated insertions and removals. The Fc / Pc connector 4 is used to connect to the laser source fiber and is located at the rear end of the pole 2. The metal connector of the Fc / Pc connector 4 is secured with screws, allowing for quick laser replacement (wavelength 0-2200nm). The five-axis displacement stage 32 controls the laser focus's displacement in the X / Y / Z directions and its pitch / tilt angle, adjusting the stage to focus the laser spot at the center of the carrier network. The five-axis displacement stage allows for precise control of the laser spot size and position.

[0040] Preferably, the five-axis displacement stage includes an X-axis displacement stage 321, a Y / Z-axis displacement stage 322, and an L-shaped tilt stage 323. The X-axis displacement stage 321 is movable in the X-axis direction and is mounted on the stage base 31. The Y / Z-axis displacement stage 322 is stacked on the X-axis displacement stage 321 but is not connected to it. The Y / Z-axis displacement stage 322 has a through mounting groove in the middle, and the Fc / Pc seat 4 is installed in the mounting groove and is movably connected to the Y / Z-axis displacement stage. That is, the Fc / Pc seat 4 is movable in the Y-axis and Z-axis directions and is mounted on the Y / Z-axis displacement stage 322. The L-shaped tilt stage 322 is fixedly mounted on the X-axis displacement stage 321 and is movably connected to the Y / Z-axis displacement stage 322. The pitch / tilt angle of the laser focus is adjusted by adjusting the pitch / tilt angle of the Y / Z-axis displacement stage 322. The pitch / tilt range of the Y / Z axis displacement stage 322 is ±15°.

[0041] Preferably, the L-shaped tilting stage 323 includes a horizontal part 3231 and a vertical part 3232. The intersection of the horizontal part 3231 and the vertical part 3232 is ball-jointed with the Y / Z axis displacement stage 322 via a metal ball 3233. The horizontal part 3231 is connected to the lower part of the Y / Z axis displacement stage 322 via a screw 3234 and a spring 3235. The lower part of the Y / Z axis displacement stage 322 has a groove, and the front end of the screw 3234 is placed in the groove, but is not threaded into the Y / Z axis displacement stage 322. The rear end of the screw 3234 is adjusted by a micrometer to move the screw 3234 forward and backward. The screw 3234 works with the metal ball 3233 to adjust the rotation of the Y / Z axis displacement stage 322 around the Z-axis, thereby driving the pitch adjustment of the Fc / Pc seat 4 around the Z-axis.

[0042] The vertical part 3232 is connected to the left side of the Y / Z axis displacement stage 322 via a screw 3236 and a spring 3237. The left side of the Y / Z axis displacement stage 322 has a groove, and the front end of the screw 3236 is placed in this groove, but not threadedly connected to the Y / Z axis displacement stage 322. The rear end of the screw 3236, in conjunction with a micrometer, adjusts the forward and backward movement of the screw 3236. The screw 3236, in conjunction with a metal ball 3233, adjusts the rotation of the Y / Z axis displacement stage 322 around the Y-axis, thereby driving the pitch adjustment of the Fc / Pc seat 4 around the Y-axis. Preferably, the spring is a spring or a disc spring. The L-shaped tilting stage 323 drives the Y / Z axis displacement stage 322 to rotate in the Y-axis and Z-axis directions respectively via two sets of independent adjusting screws (generally using ultra-fine thread screws in conjunction with disc springs for reset), thereby driving the corresponding pitch adjustment of the Fc / Pc seat 4 on the Y / Z axis displacement stage, achieving fine angle adjustment of the Fc / Pc seat 4 in two degrees of freedom.

[0043] The X-axis displacement stage 321 is equipped with a screw 3211 for adjusting the X-axis displacement. Screw 3211 is connected to the X-axis tight linear ball bearing guide. The Y / Z-axis displacement stage 322 is equipped with screws 3221 and 3222 for adjusting the Y-axis displacement and the Z-axis displacement, respectively connected to the Y / Z-axis tight linear ball bearing guides. Both the X-axis displacement stage 321 and the Y / Z-axis displacement stage 322 are driven by a precision linear ball bearing guide and a micrometer (or micrometer head). The micrometer pushes the stage along the guide direction, and springs or disc springs reset to eliminate backlash, achieving high-precision linear displacement. The Z-axis movement is achieved by lifting the load using a micrometer.

[0044] A through mounting groove 3223 is provided in the middle of the Y / Z axis displacement stage 322. The Fc / Pc seat 4 is correspondingly disposed in the mounting groove 3223. The laser interface 41 is located in the middle of the Fc / Pc seat 4, and the outer part is the mounting base 42. The upper surface of the mounting base 42 is provided with a rectangular limiting groove along the Y-axis direction. The lower end of the screw 3222 on the Y / Z axis displacement stage is placed in the rectangular limiting groove along the Y-axis direction, but is not threadedly connected to the mounting base 42. The upper surface of the mounting base 42 is connected to the Y / Z axis displacement stage by a spring (not shown). The front end of the screw 3221 on the Y / Z axis displacement stage is in contact with the right side of the mounting base 42. Preferably, the right side of the mounting base 42 is provided with a rectangular limiting groove along the Z-axis direction, and the front end of the screw 3221 is placed in the limiting groove along the Z-axis direction, but is not threadedly connected to the mounting base 42. The right side of the mounting base 42 is connected to the Y / Z axis displacement stage by a spring (not shown).

[0045] During adjustment, the screws 3221 and 3222 are adjusted forward and backward by using the micrometer caliper at their rear ends, thereby adjusting the movement of the Fc / Pc seat 4 on the Y-axis or Z-axis.

[0046] Preferably, the pigtail tip of the Fc / Pc connector has an angle, and the angle of the pigtail tip is 8°. The 8° angle pigtail design causes the reflected light to deviate from the original path by ≥15°, eliminating noise caused by uneven refractive index of the optical fiber (signal-to-noise ratio improvement ≥20dB).

[0047] The working process of the transmission electron microscope sample holder with in-situ laser loading according to the present invention is as follows:

[0048] (1) Component assembly: Press the window plate into the flange groove at the end of the rod body and lock the NBR sealing ring; fix the second lens (collimating lens) and the first lens (focusing lens) in sequence, and calibrate the distance between the two lenses to 24.17mm. The five-axis displacement stage is installed on the light shield through the displacement stage base and is connected to the sample rod head as a whole.

[0049] (2) Laser calibration: Connect the laser to the Fc / Pc socket and adjust the displacement stage to focus the light spot on the center of the carrier.

[0050] (3) In-situ testing.

[0051] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A transmission electron microscope sample holder with in-situ laser loading, characterized in that, From front-end to back-end, the following are included: The sample rod head has a hollow structure, with a first lens at the front end, and a sample carrier platform at the front end of the first lens. The rod body has a hollow structure. The front end of the rod body is coaxially connected to the rear end of the sample rod head. The rear end of the rod body is provided with a window and is sealed to the rod body. The rear end of the window is provided with a second lens, which forms a double lens group with the first lens. A five-axis displacement adjustment mechanism includes a displacement stage base, a five-axis displacement stage, and a light shield. The displacement stage base is located at the rear end of the rod and connected to the rod. The five-axis displacement stage is mounted on the displacement stage base. The light shield covers the displacement stage base and the five-axis displacement stage. The Fc / Pc holder is located on the five-axis displacement stage and is used to connect the laser source optical fiber. It is located behind the rod body. The five-axis displacement stage is used to control the laser focus displacement in the X / Y / Z directions and the pitch / tilt angle.

2. The transmission electron microscope sample holder with in-situ laser loading according to claim 1, characterized in that, The five-axis displacement stage includes an X-axis displacement stage, a Y / Z-axis displacement stage, and an L-shaped tilt stage. The X-axis displacement stage is movable in the X-axis direction and is mounted on the displacement stage base. The Y / Z-axis displacement stages are stacked on the X-axis displacement stage. The Fc / Pc seat is movable in the Y and Z-axis directions and is mounted on the Y / Z-axis displacement stage. The L-shaped tilt stage is fixedly mounted on the X-axis displacement stage and is movably connected to the Y / Z-axis displacement stages. The pitch / tilt angle of the laser focus can be adjusted by adjusting the pitch / tilt angle of the Y / Z-axis displacement stages.

3. The transmission electron microscope sample holder with in-situ laser loading according to claim 2, characterized in that, The pitch / tilt range of the Y / Z axis displacement stage is ±15°.

4. The transmission electron microscope sample holder with in-situ laser loading according to claim 2, characterized in that, The L-shaped tilting table includes a horizontal part and a vertical part. The intersection of the horizontal part and the vertical part is ball-connected to the Y / Z axis displacement table through a metal ball. The horizontal part is connected to the Y / Z axis displacement table through a first screw and a first spring. The first screw works in conjunction with the metal ball to adjust the rotation of the Y / Z axis displacement table around the Z axis, thereby driving the pitch adjustment of the Fc / Pc seat around the Z axis. The vertical part is connected to the Y / Z axis displacement stage via a second screw and a second spring. The second screw works with a metal ball to adjust the rotation of the Y / Z axis displacement stage around the Y axis, thereby driving the pitch adjustment of the Fc / Pc seat around the Y axis.

5. The transmission electron microscope sample holder with in-situ laser loading according to claim 1, characterized in that, The fiber optic tip of the Fc / Pc connector has an angled end face.

6. The transmission electron microscope sample holder with in-situ laser loading according to claim 5, characterized in that, The tip angle of the Fc / Pc connector is 8°, and the reflected light deviates from the original path by ≥15°.

7. The transmission electron microscope sample holder with in-situ laser loading according to claim 1, characterized in that, The sample carrier has a semi-circular groove in the middle for placing objects, and the diameter of the semi-circular hole is ≤100μm.

8. The transmission electron microscope sample holder with in-situ laser loading according to claim 1, characterized in that, The distance between the first lens and the second lens is 24.17 mm; The first lens has an EFL of 6.2 mm / BEL of 4.1 mm and an NIR coating of 600-1050 nm; the second lens has an EFL of 18 mm / BEL of 17.07 mm and no coating of 350-2200 nm.

9. The transmission electron microscope sample holder with in-situ laser loading according to claim 1, characterized in that, The window has an NIR coating of 600-1100nm and a single-sided reflectivity of <0.5%.

10. The transmission electron microscope sample holder with in-situ laser loading according to claim 1, characterized in that, The window is located at the rear end of the rod and is vacuum-sealed by a vacuum flange and a sealing ring.

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