Micro-area spectrum system in low-temperature in-plane vector magnetic field environment

Abstract

The invention provides a microcell spectrum system in a low-temperature in-plane vector magnetic field environment, and the system comprises a low-temperature thermostat which is used for providing a low-temperature testing environment for a sample, and the top of the low-temperature thermostat is provided with an optical window; the magnetic field generating device is arranged in the cryostat and is used for applying a magnetic field required by testing to the sample; the three-dimensional translation stage is arranged in the uniform magnetic field area of the magnetic field generation device and is used for adjusting the spatial position of the sample; the rotating table is arranged on the three-dimensional translation table through an adapter and is used for placing a sample, and an included angle between a crystal axis in a sample plane and a magnetic field is changed through rotation; the light source is arranged outside the cryostat and is used for generating exciting light; the objective lens is arranged below an optical window at the top of the cryostat, extends into the magnetic field area and is used for focusing the exciting light on the sample and collimating scattered light emitted by the sample, so that the scattered light is emitted out through the optical window; and the spectrograph is arranged above the optical window and is used for measuring the spectrum of the scattered light.

Description

Technical Field

[0001] The present disclosure relates to the technical field of micro-area vector magnetic field spectroscopy testing, and in particular to a micro-area spectroscopy system in a low-temperature in-plane vector magnetic field environment. Background Art

[0002] Recent research on two-dimensional magnetic materials has made significant progress. When excited by light, these materials generate quasiparticles such as excitons, spin waves (magnons), and phonons. The study of these quasiparticles is of great significance for the application of two-dimensional magnetic materials in fields such as spin electronics, quantum precision measurement, and condensed matter photophysics. However, due to the multidirectional nature of the spin projection in real space, different spin configurations in magnetic materials can have a significant impact on their physical properties. Accurately characterizing these properties presents challenges, necessitating the development of new experimental techniques.

[0003] Most existing cryogenic micro-area optical magnetic field systems only have a single-directional magnetic field of 9 or 12 T. Developing a two-dimensional or three-dimensional vector magnetic field requires increasing the size of the cryogenic system, which also affects the original magnetic field magnitude. For example, if the vertical magnetic field can reach a maximum of 12 T, adding a horizontal magnetic field would only reduce the vertical magnetic field to 9 T. Simultaneously, the horizontal magnetic field would only reach 4 T, far less than the vertical field. Consequently, the system's vector magnetic field would also only reach 4 T. This design combines a three-dimensional translation stage with a one-dimensional rotation stage through a compact adapter, enabling the application of a vector magnetic field of up to 12 T in any direction within the sample plane. This is crucial for studying two-dimensional magnetic materials with high critical fields. Summary of the Invention

[0004] In view of this, the present disclosure provides an easy-to-build, low-cost micro-area spectroscopy system in a low-temperature in-plane vector magnetic field environment.

[0005] One aspect of the present disclosure provides a micro-area spectroscopy system in a low-temperature in-plane vector magnetic field environment, the system comprising: a cryostat for providing a low-temperature testing environment for a sample and controlling the temperature of the sample within a range of 1.6 K to 300 K, the top of the cryostat being provided with an optical window; a magnetic field generating device disposed within the cryostat and for applying the magnetic field required for testing to the sample; a three-dimensional translation stage disposed within the magnetic field region of the magnetic field generating device and for adjusting the spatial position of the sample; a rotation stage disposed on the three-dimensional translation stage via an adapter and for placing the sample and changing the angle between the crystal axis of the sample plane and the magnetic field by rotation; a light source disposed outside the cryostat and for generating excitation light; an objective lens disposed below the optical window at the top of the cryostat and extending into the magnetic field region and for focusing the excitation light onto the sample and collimating scattered light emitted by the sample so that the scattered light is emitted through the optical window; and a spectrometer disposed above the optical window and for measuring the spectrum of the scattered light.

[0006] According to an embodiment of the present disclosure, the magnetic field generating device includes: a superconducting coil, which adjusts the magnetic field strength by changing the superconducting current, and the direction of the magnetic field is along the vertical direction.

[0007] According to an embodiment of the present disclosure, the system further includes: a first filter, disposed in front of the spectrometer, for filtering the reflected excitation light.

[0008] According to an embodiment of the present disclosure, the system further includes: a camera for observing the position of the sample and observing whether the excitation light is focused on the sample.

[0009] According to an embodiment of the present disclosure, the system further includes: a second filter, disposed before the camera, for filtering the reflected excitation light.

[0010] According to an embodiment of the present disclosure, the system further includes: a first beam splitter lens, used to change the optical path of the excitation light so that the excitation light is emitted from the optical window toward the sample; and a second beam splitter lens, used to change the optical path of the scattered light so that the scattered light is emitted toward the camera.

[0011] According to an embodiment of the present disclosure, the system further includes: a dual-mirror adjustment frame for fixing and adjusting the angles of the first beam splitter lens and the second beam splitter lens, so that the excitation light energy is reflected by the first beam splitter and then transmitted to the sample through the second beam splitter, and at the same time, the scattered light energy is reflected by the second beam splitter to the camera.

[0012] The micro-area spectroscopy system provided by the embodiments of the present disclosure in a low-temperature, in-plane vector magnetic field environment can achieve powerful vector high-field testing when a magnetic field is applied. This system can measure optically excited quasiparticles such as phonons, excitons, and magnons in two-dimensional magnetic materials, allowing for the study of their magnetic anisotropy, as well as the interactions and strong coupling between these quasiparticles. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The above and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0014] Figure 1 The schematic diagram shows the structure of a micro-area spectroscopy system in a low-temperature in-plane vector magnetic field environment proposed in the present disclosure.

[0015] Reference numerals:

[0016] 10-cryostat; 20-sample; 30-magnetic field generating device; 40-three-dimensional translation stage; 50-rotation stage; 60-adapter; 70-light source; 80-objective lens; 90-spectrometer; 100-first filter; 110-camera; 120-second filter; 131-first beam splitter lens; 132-second beam splitter lens; 140-optical window. DETAILED DESCRIPTION

[0017] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present disclosure. In the detailed description below, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0018] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise," "include," etc. used herein indicate the presence of the features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0019] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0020] When expressions such as "at least one of A, B, and C, etc." are used, they should generally be interpreted in accordance with the meaning commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0021] like Figure 1 As shown, the present disclosure provides a micro-area spectroscopy system in a low-temperature in-plane vector magnetic field environment, comprising: a cryostat 10 , a magnetic field generating device 30 , a three-dimensional translation stage 40 , a rotation stage 50 , a light source 70 , an objective lens 80 and a spectrometer 90 .

[0022] The cryostat 10 is used to provide a low-temperature testing environment for the sample 20 , and can control the temperature of the sample 20 to continuously change between 1.6K and 300K. An optical window 140 is provided on the top of the cryostat 10 .

[0023] The magnetic field generating device 30 is disposed within the cryostat 10 and is used to apply the required magnetic field to the sample 20 for testing. The direction of the magnetic field is variable and the intensity of the magnetic field is adjustable. The magnetic field distribution in the magnetic field region where the sample 20 is located is uniform.

[0024] The three-dimensional translation stage 40 is disposed within the magnetic field region of the magnetic field generating device 30 and is used to adjust the spatial position of the sample 20 in three-dimensional space.

[0025] The rotating stage 50 is mounted on the 3D translation stage 40 via an adapter 60 and is used to position the sample 20. Rotation of the rotating stage 50 changes the angle between the in-plane crystal axis of the sample 20 and the magnetic field. As the rotating stage 50 rotates, the 3D translation stage controls the rotation, ensuring that the relative position of the applied magnetic field and the sample 20 remains constant, allowing the application of any in-plane vector magnetic field direction.

[0026] The light source 70 is disposed outside the cryostat 10 and is used to generate excitation light.

[0027] The objective lens 80 is disposed below the optical window 140 at the top of the cryostat 10 and extends into the magnetic field region to focus the excitation light onto the sample 20 and collimate the scattered light emitted by the sample 20 so that the scattered light is emitted through the optical window 140 .

[0028] The spectrometer 90 is disposed above the optical window 140 and is used to measure the spectrum of the scattered light. A first filter 100 may be disposed in front of the spectrometer 90 to filter the reflected excitation light.

[0029] In the disclosed embodiment, the magnetic field generator 30 is generated by superconducting magnet coils. The magnetic field strength can be controlled by varying the superconducting current. The magnetic field is oriented vertically, and a one-dimensional rotation stage is used to adjust the crystal axis orientation of the sample 20 relative to the vertical magnetic field, enabling vector magnetic field detection of the sample's optical signal.

[0030] In the disclosed embodiment, the system may further include a camera 110, which is disposed outside the cryostat 10 and is used to observe the position of the sample 20 and whether the excitation light is focused on the sample 20 before the measurement begins. Similarly, to filter the reflected excitation light, a second filter 120 may be disposed in front of the camera 110.

[0031] To simplify the optical path structure, in the embodiment of the present disclosure, a first beam splitter lens 131 and a second beam splitter lens 132 are further provided in the micro-area spectroscopy system in a low-temperature in-plane vector magnetic field environment. The first beam splitter lens 131 is used to change the optical path of the excitation light so that the excitation light is emitted from the optical window 140 to the sample 20; the second beam splitter lens 132 is used to change the optical path of the scattered light so that the scattered light is emitted to the camera 110. To facilitate adjustment, the system also includes a dual-mirror adjustment frame for fixing and adjusting the angles of the first beam splitter lens 131 and the second beam splitter lens 132 so that the excitation light can be reflected by the first beam splitter lens 131 and then transmitted to the sample 20 through the second beam splitter lens 132. At the same time, the scattered light can be reflected by the second beam splitter lens 132 to the camera 110. When the camera 110 is required to observe the sample 20, the position of the dual-mirror adjustment frame is adjusted to move the first beam splitter lens 131 and the second beam splitter lens 132 to the optical paths of the excitation light and the scattered light. When spectrometer 90 is required to measure a spectrum, the position of the dual-mirror adjustment frame is adjusted to move first beam splitter 131 and second beam splitter 132 apart to improve the efficiency of collecting scattered signals. The two beam splitters compensate for the light deflection caused by a single beam splitter 131 / 132, ensuring that the position of the camera 110 image is consistent with the actual focus position of the laser.

[0032] As an example, this system can be used to measure the anisotropic Zeeman splitting of two-dimensional antiferromagnetic NiPS3 and its spin orientation as a function of a vector magnetic field. Under zero magnetic field, NiPS3 exhibits in-plane zigzag antiferromagnetism, with interlayer ferromagnetic coupling and spins along the a-axis. By applying a magnetic field and rotating the one-dimensional rotation stage 50, the angle between the spin orientation of sample 20 and the magnetic field can be adjusted. The three-dimensional translation stage 40 is adjusted to move sample 20, ensuring that the axis of rotation of the rotation stage 50 is within the sample 20 surface. This ensures that the laser focus position on sample 20 remains constant during rotation of the one-dimensional rotation stage 50. The three-dimensional adjustment platform is then adjusted to align the incident light with the center of the objective lens 80, ensuring that the incident light passing through the objective lens 80 is focused on the surface of the two-dimensional NiPS3 sample 20. By placing the sample 20 at a low temperature and rotating the one-dimensional rotation stage 50, the angle between the spin orientation of the sample 20 and the magnetic field can be adjusted. For NiPS3, the direction of the spin can be determined by polarized PL spectroscopy and Zeeman splitting spectroscopy under a magnetic field, and then the physics involved, such as the magnetic anisotropy of excitons and magnons, and the regulation of the interaction between phonons and magnons by a vector magnetic field, can be studied.

[0033] The above examples demonstrate that this system can perform spectroscopic measurements at low temperatures and in vector magnetic field environments. This solution is highly suitable for vector magnetic field spectroscopy measurements at low temperatures and in extremely small spaces. The system is simple and efficient to implement and operate. It can be applied to the study of spectral-related properties of two-dimensional magnetic materials and is suitable for widespread use in laboratories.

[0034] The above describes the embodiments of the present disclosure. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present disclosure. Although each embodiment has been described separately above, this does not mean that the measures in each embodiment cannot be advantageously used in combination. Without departing from the scope of the present disclosure, those skilled in the art may make various substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A micro-area spectroscopy system in a low-temperature in-plane vector magnetic field environment, characterized in that: The system comprises: A cryostat (10) is used to provide a low-temperature testing environment for a sample (20) and control the temperature of the sample (20) within a range of 1.6 K to 300 K. An optical window (140) is provided on the top of the cryostat (10); a magnetic field generating device (30), disposed in the cryostat (10), for applying a magnetic field required for testing to the sample (20); A three-dimensional translation stage (40), disposed within the magnetic field region of the magnetic field generating device (30), and used for adjusting the spatial position of the sample (20); A rotating stage (50) is arranged on the three-dimensional translation stage (40) via an adapter (60) and is used to place the sample (20) and change the angle of the crystal axis in the plane of the sample (20) relative to the magnetic field by rotation; a light source (70) disposed outside the cryostat (10) and configured to generate excitation light; an objective lens (80) disposed below the optical window (140) at the top of the cryostat (10) and extending into the magnetic field region, for focusing the excitation light onto the sample (20) and collimating scattered light emitted by the sample (20) so that the scattered light is emitted through the optical window (140); A spectrometer (90) is provided above the optical window (140) and is used to measure the spectrum of the scattered light.

2. The micro-area spectroscopy system in a low-temperature in-plane vector magnetic field environment according to claim 1, characterized in that: The magnetic field generating device (30) comprises: Superconducting magnet coils; The magnetic field generating device (30) regulates the magnetic field intensity by changing the superconducting current, and the direction of the magnetic field is along the vertical direction.

3. The micro-area spectroscopy system in a low-temperature in-plane vector magnetic field environment according to claim 1, characterized in that: The system further comprises: The first filter (100) is arranged in front of the spectrometer (90) and is used to filter the reflected excitation light.

4. The micro-area spectroscopy system in a low-temperature in-plane vector magnetic field environment according to claim 1, characterized in that: The system further comprises: The camera (110) is used to observe the position of the sample (20) and to observe whether the excitation light is focused on the sample (20).

5. The micro-area spectroscopy system in a low-temperature in-plane vector magnetic field environment according to claim 4, characterized in that: The system further comprises: The second filter (120) is arranged before the camera (110) and is used to filter the reflected excitation light.

6. The micro-area spectroscopy system in a low-temperature in-plane vector magnetic field environment according to claim 4, characterized in that: The system further comprises: a first beam splitter lens (131) for changing the optical path of the excitation light so that the excitation light is emitted from the optical window (140) toward the sample (20); The second beam splitting lens (132) is used to change the optical path of the scattered light so that the scattered light is directed toward the camera (110).

7. The micro-area spectroscopy system in a low-temperature in-plane vector magnetic field environment according to claim 6, characterized in that: The system further comprises: A double-mirror adjustment frame is used to fix and adjust the angles of the first beam splitter lens (131) and the second beam splitter lens (132), so that the excitation light energy is reflected by the first beam splitter lens (131) and then transmitted to the sample (20) through the second beam splitter lens (132), and at the same time, the scattered light energy is reflected by the second beam splitter lens (132) to the camera (110).

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