Method and target for measuring transient conductivity of transparent material under shock compression

Abstract

The embodiment of the invention discloses a method and a target for measuring transient conductivity of a transparent material under shock compression, the method is applied to the transient conductivity measuring target, and the transient conductivity measuring target comprises a container for accommodating a transparent material sample, a pair of electrodes arranged on the container and at least one group of optical probes for optical detection; the method comprises the following steps: loading a transparent material sample in the transient conductivity measurement target by utilizing shock waves; in the impact loading process, the following operations are synchronously executed: measuring the total conductivity of the transparent material sample through a pair of electrodes by adopting a two-electrode method; measuring the electronic conductivity of the transparent material sample by adopting an optical reflection method through at least one group of optical probes; according to the invention, the total conductivity and the electronic conductivity can be measured synchronously and continuously without interference in the same impact event, and the measurement precision of the conductivity of the material under extreme conditions can be improved.

Description

Technical Field

[0001] This application relates to the field of material conductivity measurement technology, and in particular to a method for measuring the transient conductivity of transparent materials under impact compression and a measurement target. Background Technology

[0002] In extreme condition studies such as shock wave physics, astrophysics, and inertial confinement fusion, the transient conductivity of materials is a key parameter for revealing their ionization, conduction mechanisms, and phase transition processes under high temperature and pressure. Currently, conductivity measurement methods under impact loading, such as the two-electrode method, can measure the total DC conductivity, which characterizes the directional migration capability of charge carriers, while optical reflection methods can indirectly obtain electronic conductivity. However, existing technologies lack effective means to simultaneously, continuously, and without interference measure the total conductivity and electronic conductivity in the same impact event. Especially in special states such as the superionic state, the ratio between the two is unknown, and stepwise or asynchronous measurements will fail to accurately capture the dynamic behavior of materials and reveal their microscopic physical mechanisms. Summary of the Invention

[0003] The purpose of this application is to provide a method for measuring the transient conductivity of transparent materials under impact compression and a transient conductivity measurement target, which can simultaneously, continuously and without interference measure the total conductivity and electronic conductivity in the same impact event, thereby improving the measurement accuracy of the material's conductivity properties under extreme conditions.

[0004] This application provides a method for measuring the transient conductivity of a transparent material under impact compression. The technical solution is as follows: the method is applied to a transient conductivity measuring target, which includes a container holding a transparent material sample, a pair of electrodes disposed on the container, and at least one set of optical probes for optical detection; the method includes: loading the transparent material sample in the transient conductivity measuring target with a shock wave; during the impact loading process, simultaneously performing the following operations: measuring the total conductivity of the transparent material sample using a two-electrode method through the pair of electrodes; and measuring the electronic conductivity of the transparent material sample using an optical reflection method through at least one set of optical probes.

[0005] Furthermore, this application also proposes a method for measuring the total conductivity of a transparent material sample using a two-electrode method, comprising: constructing a measurement circuit, the measurement circuit including a power supply, a branch to be measured connected to a pair of electrodes, a reference resistor branch, and a protective resistor; receiving a trigger signal to close a switch in the measurement circuit before the shock wave reaches the transparent material sample, thereby turning on the measurement circuit; monitoring the voltage change of the branch to be measured or the reference resistor branch; calculating the resistance value of the transparent material sample based on the voltage change, and obtaining the total conductivity based on the resistance value.

[0006] Furthermore, this application also proposes that the resistance value of the protective resistor is greater than the resistance value of the reference resistor and the resistance value of the transparent material sample under impact compression.

[0007] Furthermore, this application also proposes a method for measuring the electronic conductivity of a transparent material sample using an optical reflection method, comprising: emitting probe light onto the transparent material sample through an optical probe; receiving reflected light signals from the front and back interfaces of the transparent material sample; determining the reflectivity of the transparent material sample based on the reflected light signals; and calculating the AC conductivity of the transparent material sample in the optical frequency band based on the reflectivity, so as to determine the AC conductivity as the electronic conductivity.

[0008] Furthermore, this application also proposes to calculate the AC conductivity of a transparent material sample in the optical frequency band based on reflectivity: the complex refractive index of the transparent material sample is calculated based on reflectivity; the complex dielectric constant is obtained based on the calculation formula of complex refractive index and complex dielectric constant; and the AC conductivity in the optical frequency band is calculated based on the calculation formula of complex dielectric constant and AC conductivity.

[0009] Furthermore, this application also proposes that a metal reflective film be provided on the rear interface to enhance the reflected light signal; the thickness of the metal reflective film is 100 nanometers to 1 micrometer.

[0010] Furthermore, this application also proposes a transient conductivity measurement target, comprising: a transparent substrate; a container for containing a transparent material sample, disposed on the transparent substrate; a pair of electrodes disposed on the container for connecting an external measurement circuit to perform a two-electrode method measurement; at least one set of optical probes whose optical paths are configured to detect the transparent material sample inside the container; and a metal reflective film disposed at the interface between the transparent substrate and the container, or directly disposed on the surface of the transparent substrate facing the container; wherein the transient conductivity measurement target is used to implement the above-mentioned method for measuring the transient conductivity of a transparent material under impact compression.

[0011] Furthermore, this application also proposes that the optical probe includes an incident optical fiber and a receiving optical fiber, wherein the incident optical fiber is used to guide the probe light to the front and / or rear interface of the container, and the receiving optical fiber is used to receive reflected light from the corresponding interface.

[0012] Furthermore, this application also proposes that the transient conductivity measurement target is connected to an external measurement circuit, which includes a power supply, a switch, a reference resistor, and a protection resistor; the switch is configured to turn on in response to a trigger signal before the shock wave reaches the transparent material sample.

[0013] Furthermore, this application also proposes that the switch be located at the power output terminal or in a circuit consisting of a pair of electrodes.

[0014] As can be seen from the above, the method for measuring the transient conductivity of transparent materials under impact compression and the transient conductivity measurement target provided in this application achieve simultaneous acquisition of two key parameters in a single impact event by simultaneously performing the two-electrode method to measure the total conductivity and the optical reflection method to measure the electronic conductivity. It has the advantages of being able to measure the total conductivity and electronic conductivity synchronously, continuously and without interference in the same impact event, effectively solving the problems of inconsistent material states and loss of time correlation information caused by step-by-step measurement, and improving the measurement accuracy of material conductivity properties under extreme conditions.

[0015] Of course, any product implementing this application does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A structural diagram of the transient conductivity measurement target provided in the embodiments of this application;

[0018] Figure 2 The structural diagram of the transient conductivity measurement target provided in the embodiments of this application is a flowchart of the steps of the method for measuring the transient conductivity of transparent materials under impact compression provided in the embodiments of this application.

[0019] Figure 3 A schematic diagram of the measurement circuit in the method for measuring the transient conductivity of a transparent material under impact compression provided in the embodiments of this application;

[0020] Figure 4 The flowchart of the conductivity measurement target operation in the method for measuring the transient conductivity of transparent materials under impact compression provided in the embodiments of this application is shown. Detailed Implementation

[0021] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0022] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms "a" and "the" as used in the embodiments of this application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0023] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0024] In current technologies, research on extreme conditions such as shock wave physics, astrophysics, and inertial confinement fusion requires the simultaneous acquisition of total conductivity and electronic conductivity to reveal the dynamic behavior of materials. Traditional methods use the two-electrode method and optical reflection method to measure DC total conductivity and optical electronic conductivity, respectively. However, current technologies cannot achieve simultaneous execution of both measurements within the same shock event. Stepwise or asynchronous measurements result in poor data temporal correlation, especially in special states such as the superionic state, making it impossible to accurately capture the dynamic changes in materials.

[0025] To address the aforementioned issues, the lack of synchronization and measurement interference in existing technologies have become key obstacles. Analysis reveals that the measurement principles of total conductivity and electronic conductivity differ: the two-electrode method relies on current signals, while the optical reflection method relies on light signals; these two methods are complementary in their physical mechanisms. If non-interfering measurement paths can be designed for the same impact event, and time-synchronized triggering can be ensured, simultaneous acquisition of both parameters may be possible. Further considering the rapid changes in material state under impact loading, a measurement structure capable of withstanding high pressure while maintaining signal stability needs to be constructed.

[0026] Therefore, this application proposes a measurement method for a transient conductivity measurement target, which includes loading a transparent material sample with a shock wave and simultaneously performing the following operations during the shock loading process: measuring the total conductivity using a two-electrode method with a pair of electrodes, and measuring the electronic conductivity using an optical reflection method with at least one set of optical probes.

[0027] The present application will be further described below with reference to the accompanying drawings.

[0028] refer to Figure 1 , Figure 1This is a structural diagram of a transient conductivity measurement target provided in an embodiment of this application. The measurement target has a layered structure, which sequentially includes a window serving as an impact loading surface, a container for accommodating the sample to be tested, and a substrate serving as an optical substrate. Electrodes are disposed on the container and immersed in the sample for performing two-electrode electrical measurements. At least one set of optical fibers is integrated into the measurement target, and its optical path passes through the window and extends to the sample area for emitting probe light to the sample and receiving reflected light from the sample-substrate interface. A metal reflective film is disposed on the side of the substrate facing the sample to enhance the reflected light signal. The shock wave is incident from one side of the window, penetrates the window, and applies planar loading to the sample.

[0029] In some embodiments, Figure 1 The target cross-section is shown below. The direction of impact is shown at the bottom. The total conductivity is measured using the two-electrode method. To ensure the measurement of the material's reflectivity and absorptivity during the impact, optical fiber simultaneously measures the reflected light at the front and rear interfaces of the material. The reflectivity is measured by the reflected signal, and the absorptivity is measured by the signal intensity at the front and rear interfaces. To ensure that the reflected light at the rear interface is clearly visible and unaffected during measurement, a 100-nanometer to 1-micrometer thick metal film is deposited in the reflected light region of the rear interface. If the substrate material is non-reflective, a film can also be deposited at the corresponding location on the substrate.

[0030] The assembly and usage steps of its measurement system are as follows:

[0031] The first step is to connect the circuit and the test target, and measure the influence of conductivity, thickness parameters, etc. on the resistance to be tested.

[0032] The second step is to confirm relevant parameters such as target thickness;

[0033] The third step is to connect the optical fiber and the target, and confirm that the light from the two sets of optical fibers hits the metal reflective surface and is reflected back to the optical fiber.

[0034] The fourth step is to start the experiment. The light can be turned on in advance, and the circuit switch is triggered by the experimental trigger signal.

[0035] The fifth step is to process the experimental data and confirm the magnitudes of total conductivity and electronic conductivity.

[0036] This invention proposes a method for measuring the real-time total conductivity and electronic conductivity of transparent materials, which enables high-precision measurement of liquid conductivity changes over time. The experiment employs a two-electrode method for total conductivity and an optical reflection method for electronic conductivity, ensuring that the two methods do not interfere with each other and clearly measure the entire process of material conductivity changes.

[0037] refer to Figure 2 , Figure 2The structural diagram of the transient conductivity measuring target provided in this application embodiment is a flowchart of the steps of the method for measuring the transient conductivity of a transparent material under impact compression provided in this application embodiment; this application provides a method for measuring the transient conductivity of a transparent material under impact compression. The method is applied to a transient conductivity measuring target, which includes a container for containing a transparent material sample, a pair of electrodes disposed on the container, and at least one set of optical probes for optical detection; the method includes the following steps:

[0038] Step 201: Load the transparent material sample in the transient conductivity measurement target with a shock wave;

[0039] Step 202, during the impact loading process, perform the following operations simultaneously:

[0040] Step 203: Measure the total conductivity of the transparent material sample using the two-electrode method with a pair of electrodes;

[0041] Step 204: Measure the electronic conductivity of the transparent material sample using the optical reflection method through at least one set of optical probes.

[0042] Shock wave loading refers to applying a pressure wave generated by an external shock source to a transparent material sample, placing it in a high-pressure transient state. This can be achieved using a gas cannon or a laser-driven shock wave device to simulate extreme physical conditions. The two-electrode method for measuring total conductivity involves applying a DC voltage to the sample using a pair of electrodes and measuring the current response. Specifically, a circuit including a power supply, reference resistor, and protection resistor can be constructed. By monitoring voltage changes, the resistance value is calculated, reflecting the carrier migration capability. The optical reflection method for measuring electronic conductivity involves illuminating the sample interface with probe light and analyzing reflectivity changes. A fiber optic probe can be used to transmit and receive optical signals. The AC conductivity in the optical frequency band is derived from the relationship between complex refractive index and complex permittivity, reflecting the free electron motion characteristics. Synchronous execution means that both measurements start simultaneously after the shock wave arrives at the sample and continuously acquire data. This is achieved by synchronizing the timing of the circuit switch with the optical detection system using a trigger signal, ensuring consistency in the timelines of the two measurements.

[0043] Understandably, when a shock wave acts on a transparent material sample, the carrier concentration and mobility inside the sample change rapidly. The two-electrode method calculates the total conductivity by measuring the voltage change in the circuit, reflecting the combined conductivity of ions and electrons; the optical reflection method derives the electronic conductivity in the optical frequency band by analyzing the changes in reflected light intensity at the front and back interfaces. Both measurements utilize the different propagation characteristics of electrical and optical signals, respectively, and avoid mutual interference through physical isolation of the circuit and optical path or time-division multiplexing techniques. For example, high-frequency filtering is used in circuit design to suppress the influence of optical signals on electrical measurements, or specific wavelengths are used in the optical path to avoid circuit noise frequencies.

[0044] Compared to existing technologies, traditional methods require separate measurements of total conductivity and electronic conductivity in two experiments, resulting in poor temporal correlation of the data and an inability to capture dynamic changes under the same impact event. This proposed method, through synchronous triggering and signal isolation design, simultaneously acquires both parameters in a single impact loading event, solving the problem of difficult correlation analysis of carrier behavior during transient processes such as the superionic state. Furthermore, by combining the complementarity of electrical and optical measurements, the ionization mechanism of materials under extreme conditions can be revealed more comprehensively.

[0045] Through the above technical solution, this application achieves simultaneous measurement of total conductivity and electronic conductivity under the same impact event, eliminating the time error and state difference introduced by step-by-step measurement, and providing a reliable data foundation for studying the carrier dynamics of materials in high-pressure transient processes. Through the synergistic analysis of electrical and optical signals, the contribution ratio of ionic conductivity and electronic conductivity can be accurately distinguished, thereby revealing the dynamic evolution of microscopic mechanisms such as phase transitions and ionization in materials.

[0046] This application further proposes to construct a measurement circuit, which includes a power supply, a test branch connected to a pair of electrodes, a reference resistance branch, and a protection resistor; at a moment before the shock wave reaches the transparent material sample, a trigger signal is received to close the switch in the measurement circuit so that the measurement circuit is turned on; the voltage change of the test branch or the reference resistance branch is monitored; the resistance value of the transparent material sample is calculated based on the voltage change, and the total conductivity is obtained based on the resistance value.

[0047] The measurement circuit is a closed loop comprising a power supply, the branch under test, a reference resistor branch, and a protective resistor. A constant voltage source or pulse power supply can be used as the power supply. The branch under test and the reference resistor branch are connected in parallel, and the protective resistor is connected in series in the loop to limit current and prevent circuit overload. The reference resistor branch is a parallel branch containing resistors of known resistance values, which can be implemented using precision resistors or adjustable resistors. By comparing the voltage changes between the branch under test and the reference branch, the sample resistance value can be indirectly calculated. The protective resistor is a current-limiting element with a resistance value greater than the reference resistor and the resistance value of the transparent material sample under impact compression. It can be implemented using high-resistance wire-wound resistors or thin-film resistors, and its function is to prevent damage to the measuring equipment due to short circuits or overcurrent. The trigger signal is a timing signal that controls the closing of the switch, which can be generated using photoelectric triggering or mechanical triggering to ensure that the switch closes before the shock wave reaches the sample, thus achieving synchronization of conductivity measurement.

[0048] refer to Figure 3 , Figure 3This application provides a method for measuring the transient conductivity of transparent materials under impact compression, illustrated in the following schematic diagram of the measurement circuit. The measurement circuit includes a power supply V, a protective resistor represented by R1, a reference resistor represented by R2 in the reference resistor branch, and the resistance to be measured in the branch under test (i.e., the resistance of the transparent material sample), connected to a pair of electrodes, represented by Rx. A trigger signal is connected to the switch control terminal in the circuit to close the switch instantaneously before the shock wave arrives, thus turning on the circuit. By monitoring the voltage change across R2 or Rx, the resistance value of Rx can be calculated based on the voltage change, thereby obtaining the total conductivity. It is understood that before the shock wave reaches the transparent material sample, after the trigger signal is received, the switch closes, turning on the measurement circuit. At this time, the power supply supplies power to the branch under test and the reference resistor branch, and the transparent material sample in the branch under test and the reference resistor branch form a parallel circuit. Due to the high resistance of the protective resistor, most of the voltage drops across it, thus protecting the measurement circuit. By monitoring the voltage changes of the branch under test or the reference resistor branch in real time, and combining this with Ohm's law, the real-time resistance value of the sample can be calculated, and the total conductivity can then be derived. For example, when a shock wave causes the sample resistance to decrease, the voltage of the branch under test will also decrease. By comparing the proportion of voltage change in the reference resistor branch, the interference of power supply fluctuations on the measurement can be eliminated.

[0049] Compared with existing technologies, current two-electrode methods often suffer from circuit damage or data distortion due to sudden current changes during impact loading, and lack synchronous trigger control for transient processes. This solution introduces a protective resistor and a reference resistor branch to achieve differential voltage measurement while limiting current, significantly improving anti-interference capability; and precisely controls the switch closing timing with a trigger signal to ensure strict synchronization between measurement and impact loading, avoiding data loss due to timing deviations.

[0050] Through the above technical solution, this application solves the problems of transient conductivity measurement being easily affected by circuit overload interference and inaccurate timing control in the prior art, and realizes stable and continuous measurement of the total conductivity of transparent materials during impact compression, providing a reliable circuit basis for synchronously obtaining total conductivity and electronic conductivity.

[0051] This application further proposes that the resistance value of the protective resistor is greater than the resistance value of the reference resistor and the resistance value of the transparent material sample under impact compression.

[0052] The protective resistor is a current-limiting element connected in series in the measurement circuit. It can be implemented using a high-precision metal film resistor or a wire-wound resistor, and its resistance value can be more than ten times that of the reference resistor. The reference resistor is a standard resistor connected in parallel in the branch under test. It can be made of an alloy material with a low temperature coefficient and is used to construct a voltage divider circuit to calculate the resistance value of the sample under test. The resistance value under shock compression refers to the dynamic resistance of a transparent material formed by lattice deformation and changes in carrier concentration during shock wave loading. Its value may be lower than the resistance value under normal conditions.

[0053] Understandably, the measurement circuit enters its operational state by closing a switch before the shock wave reaches the sample. Because the resistance of the protective resistor is significantly higher than that of the reference resistor and the sample's dynamic resistance, the current in the circuit primarily flows through the reference resistor branch and the sample branch. When the shock compression causes a sudden drop in sample resistance, the protective resistor limits the total current intensity to prevent circuit overload, while simultaneously maintaining the voltage signal in the reference resistor branch within the measurable range. This resistance configuration allows for accurate separation of the voltage contributions from the reference resistor and the sample resistance during total conductivity calculation.

[0054] Compared to existing technologies, conventional two-electrode methods do not explicitly define the resistance values ​​of the protective resistors. When the sample exhibits extremely low resistance under impact compression, the voltage signal of the reference resistor branch may be distorted due to the shunt effect. This solution effectively suppresses signal distortion caused by impedance abrupt changes during dynamic measurements by defining the resistance levels of the protective resistors.

[0055] Through the above technical solution, this application achieves stable control of the circuit's operating state during impact compression, ensuring the reliability of the total conductivity measurement data. Especially when the sample enters a low-resistance state such as the superionic state, the resistance configuration can maintain a stable signal ratio between the reference resistance branch and the branch under test, avoiding measurement errors caused by current distribution imbalance.

[0056] This application further proposes a method for measuring the electronic conductivity of transparent material samples using optical reflection, including emitting probe light into the transparent material sample through an optical probe; receiving reflected light signals from the front and back interfaces of the transparent material sample; determining the reflectivity of the transparent material sample based on the reflected light signals; and calculating the AC conductivity of the transparent material sample in the optical frequency band based on the reflectivity, so as to determine the AC conductivity as the electronic conductivity.

[0057] The optical probe is a device used to emit and receive optical signals. Specifically, it can be implemented using a fiber optic probe or an integrated photoelectric sensor. Its function is to ensure that the probe light is accurately incident on the sample interface and capture the reflected light signal. The reflected light signal refers to the light reflection phenomenon caused by the difference in refractive index at the material interface. Specifically, it can be achieved by separating the reflected light from the front and back interfaces using a beam splitter or photodetector, providing information on the dynamic changes in the interface's optical properties. Reflectivity is the ratio of incident light intensity to reflected light intensity, which can be calculated using a photoelectric conversion and signal processing module. Its function is to reflect the changes in electron density and mobility of the material during impact compression. Alternating current conductivity refers to the material's ability to conduct electricity under the influence of optical frequency electromagnetic fields. It can be derived from the relationship between complex refractive index and complex permittivity, characterizing the response characteristics of free electrons to high-frequency electric fields.

[0058] Understandably, during impact loading, an optical probe emits probe light of a specific wavelength towards a transparent material sample. The front and rear interfaces generate reflected light signals due to the difference in refractive index between the material and the surrounding medium. By separating and measuring the intensity of the two reflected beams, the reflectivity change of the material under dynamic compression can be calculated in real time. Based on the physical model of electromagnetic wave-matter interaction, reflectivity is directly related to the complex refractive index of the material, and the imaginary part of the complex refractive index corresponds to the AC conductivity in the optical frequency band. Therefore, by establishing a quantitative relationship between reflectivity and AC conductivity, the transient evolution data of the material's electronic conductivity during impact compression can be directly obtained.

[0059] Compared to existing technologies, traditional optical reflection methods typically only measure a single interface or static sample, failing to simultaneously capture reflection signals from the front and rear interfaces under extreme impact loading conditions. This approach eliminates errors caused by material thickness variations or shock wave propagation in single-interface measurements through joint analysis of reflected light signals from both interfaces. Furthermore, by utilizing the direct correlation between AC conductivity and electron mobility in the optical frequency band, it achieves high-precision dynamic measurement of electronic conductivity.

[0060] Through the above technical solution, this application can simultaneously acquire the total electrical conductivity and electronic conductivity data of transparent materials in the same impact event, solving the problem of time asynchrony caused by step-by-step measurement. Direct calibration of electronic conductivity using optical reflection method can accurately distinguish the contribution ratio of ionic conductivity to electronic conductivity during impact compression, providing a reliable technical means for studying the ionization mechanism and phase transition dynamics of materials under extreme conditions.

[0061] This application further proposes a method for calculating the AC conductivity of a transparent material sample in the optical frequency band based on reflectivity, including calculating the complex refractive index of the transparent material sample based on reflectivity, obtaining the complex dielectric constant based on the calculation formula of complex refractive index and complex dielectric constant, and then calculating the AC conductivity in the optical frequency band based on the calculation formula of complex dielectric constant and AC conductivity.

[0062] Complex refractive index is a complex numerical parameter that comprehensively characterizes the refraction and absorption properties of a material for light waves. It can be obtained by simultaneously solving the reflectivity and Fresnel equations, for example, using the Kramers-Kronig relation or iterative fitting algorithms. Complex permittivity is a mathematical description of the polarization and loss behavior of a material in an alternating electric field. It can be derived from the correspondence between the square of the complex refractive index and the real and imaginary parts of the permittivity. Alternating current conductivity refers to the conductivity of a material in the optical frequency band due to electron motion. It can be calculated by the product of the imaginary part of the complex permittivity and the angular frequency.

[0063] Understandably, during the impact compression process, the change in the optical reflectivity of the transparent material is measured in real time. First, a calculation model for the complex refractive index is established using the reflectivity data combined with the electromagnetic field boundary condition equations. For example, when probe light is incident on the sample's front interface, there is a definite mathematical relationship between the real and imaginary parts of the reflectivity and the complex refractive index. The specific value of the complex refractive index can be obtained by solving a system of simultaneous equations. Subsequently, the complex refractive index is substituted into the formula for calculating the complex permittivity; for example, the square of the complex refractive index is equal to the complex permittivity, thus separating the real and imaginary parts of the permittivity. Finally, multiplying the imaginary part of the permittivity by the angular frequency of the light wave yields the AC conductivity value of the material in the optical frequency band.

[0064] Compared to existing technologies, traditional optical reflection methods typically only qualitatively determine conductivity trends through reflectivity changes, lacking a complete mathematical model for quantitatively calculating AC conductivity. For example, existing technologies may rely solely on empirical relationships between reflectivity and conductivity, leading to significantly increased errors under extreme conditions such as the superionic state. This method establishes a progressive calculation chain from complex refractive index to complex permittivity to AC conductivity, achieving precise conversion from optical signals to electronic conductivity parameters.

[0065] Through the above technical solution, this application can directly convert transient reflectivity data into quantitative values ​​of AC conductivity in the optical frequency band, solving the problem that traditional methods cannot simultaneously obtain accurate electronic conductivity values ​​during impact events. This method, through coupled calculations of multi-step physical models, ensures the dynamic characterization accuracy of electronic conductivity behavior during material phase transitions or ionization processes, providing a reliable data foundation for analyzing the microscopic conductivity mechanisms of materials under extreme conditions.

[0066] This application further proposes that the rear interface is provided with a metal reflective film to enhance the reflected light signal, and the thickness of the metal reflective film is 100 nanometers to 1 micrometer.

[0067] The metal reflective film refers to a thin metal film layer attached to the interface between the transparent substrate and the container, or to the surface of the transparent substrate facing the container. It can be achieved by depositing materials such as aluminum, silver, or gold using vacuum evaporation or magnetron sputtering processes. Its function is to enhance the intensity of reflected light at the interface through high reflectivity, thereby improving the signal-to-noise ratio of optical reflection methods for measuring electronic conductivity. The thickness of 100 nanometers to 1 micrometer refers to the vertical dimension range of the metal reflective film, which can be achieved by controlling the deposition time or process parameters. This range balances reflection efficiency and light absorption effects. For example, a thickness less than 100 nanometers may result in insufficient reflectivity, while a thickness exceeding 1 micrometer may affect structural stability due to increased light absorption or excessive film stress.

[0068] Understandably, during the impact compression process, when the probe light is incident on the transparent material sample, the reflected light from the front and rear interfaces is significantly enhanced due to the presence of the metal reflective film. Especially with the increased signal intensity of the reflected light from the rear interface, the optical probe can more clearly capture the interference or phase change of the two reflected beams. By analyzing the reflected light signal, the reflectivity of the transparent material sample can be accurately calculated, and the electronic conductivity can be derived. The thickness of the metal reflective film is controlled within the range of 100 nanometers to 1 micrometer, ensuring sufficient reflectivity while avoiding problems such as increased light absorption or interface stress concentration due to excessive film thickness, thus ensuring the synchronization and reliability of optical measurement and the impact loading process.

[0069] Compared to existing technologies, traditional optical reflection methods may lead to measurement errors under impact loading due to weak interface reflection signals, especially when no reflective layer is placed at the back interface of transparent material samples, resulting in insufficient reflected light intensity and susceptibility to environmental noise interference. This application, however, significantly enhances the back interface reflected light intensity by placing a metal reflective film of a specific thickness at the interface between the transparent substrate and the container or on the surface of the transparent substrate. This enables the optical reflection method to stably acquire high signal-to-noise ratio signals during the transient process of impact compression, thereby improving the accuracy of electronic conductivity measurement.

[0070] Through the above technical solution, this application solves the problem of inaccurate electronic conductivity measurement caused by weak reflected light signal in the prior art. By optimizing the position and thickness of the metal reflective film, it ensures that high-precision electronic conductivity data can be obtained simultaneously under extreme impact conditions, providing a reliable basis for analyzing the conductivity mechanism of transparent materials under high pressure and high temperature.

[0071] refer to Figure 4 , Figure 4The method for measuring the transient conductivity of transparent materials under impact compression provided in this application includes a flowchart of the conductivity measurement target operation. In some embodiments, the specific implementation process of the conductivity measurement target operation in this application method may include: First, connecting the measurement circuit as required and calibrating the measurement system; then, connecting the circuit to the measurement target and confirming key parameters such as the thickness of the transparent material sample; subsequently, connecting at least one set of optical probes, such as two optical fibers, to the measurement target and confirming that they can effectively receive reflected light from the front and back interfaces of the transparent material sample; then, performing experimental measurements, wherein the probe light is turned on before the experiment, and a trigger signal is used to control the switch in the measurement circuit to ensure that the circuit is turned on for a very short time before the shock wave reaches the sample, so as to avoid polarization effects and achieve synchronous measurement; finally, processing the collected voltage data and optical reflection data to calculate the total conductivity and electronic conductivity of the transparent material sample.

[0072] In some embodiments, the specific process of measuring the electronic conductivity of the transparent material sample using the optical reflection method in this application can be as follows: Let the AC conductivity of the material be expressed as:

[0073]

[0074] in, The real part represents the lossy component, which is related to the component of the current that is in phase with the electric field, converting electrical energy into heat (resistivity). The imaginary part represents the non-dissipative component, which is related to the component of the current that lags behind the electric field by 90 degrees, representing the temporary storage and release of energy (reactivity, similar to capacitive or inductive). Typically, there are... This conductivity describes the comprehensive dynamic response of charge carriers to an alternating electric field, containing rich physical information such as carrier relaxation, scattering processes, and resonant absorption. When the frequency is 0, the AC conductivity is:

[0075]

[0076] at this time, At this point, there is only the corresponding loss, and there is no energy storage or release process.

[0077] It is understandable that light, during its propagation, can be considered an electromagnetic wave, thus possessing an oscillating electric field. Its propagation within a material is affected by the alternating current conductivity. The real part of the alternating current conductivity describes the component of the current that oscillates synchronously and in phase with the electric field. This component is the portion lost as heat, absorbed by the material. The temporary storage and release of the imaginary part primarily affects the refraction and reflection of light. The conductivity obtained by the electrode method through direct current measurement is naturally the direct current conductivity.

[0078] It is worth noting that the material will exhibit a polarization effect due to prolonged direct current application. To mitigate the impact of this polarization effect, the experimental circuit must only be activated during measurement. The experimental circuit is as follows: Figure 3 As shown in the diagram, a trigger signal is used to open the switch, ensuring the circuit is connected only a short time before the impact. In the circuit... The resistor to be measured is the resistance of the liquid container. As a reference resistor, it needs to be compared with the measured resistance. Get as close as possible. To protect the resistance, it needs to be much larger than and .when When the value reaches the value to be measured from infinity or a relatively large value. Because Much larger and At this point, the change in total circuit resistance is small, and the change in current is negligible, so it can be considered a constant. Because the change in resistance results in a significant change in voltage at this point, the measured voltage value can be used to obtain... Value, that is

[0079]

[0080] in for The initial resistance is usually infinite. This is the initial voltage. This is for measuring voltage. In this way, changes in resistance can be obtained from changes in voltage.

[0081] According to Ampere's law in Maxwell's equations, we can obtain...

[0082]

[0083] The free current term and displacement current term Represented by electric field

[0084]

[0085] For time-harmonic fields, we can obtain

[0086]

[0087] At this time, the relative permittivity is

[0088]

[0089] Then, based on the relationship between dielectric constant and refraction, we can obtain...

[0090]

[0091] It mainly affects light refraction and reflection. It primarily affects light absorption. Therefore, by measuring light absorption and reflection data, AC conductivity information can be obtained. Since free electrons affect high-frequency light (~10⁻¹⁰),... 14 The reflectance of the liquid interface is measured using short-wavelength light (Hz) as the probe light. Therefore, the experiment uses short-wavelength light to measure the reflectance of the liquid interface. According to the reflectance formula...

[0092]

[0093] in Generally, it is 0 in negative refractive index. It can be approximated as

[0094]

[0095] At this point, by confirming the refractive index of the known side of the reflecting interface, the refractive index of the liquid to be measured can be obtained, and thus the electronic conductivity can be obtained.

[0096] This application further proposes a transient conductivity measurement target, including a transparent substrate; a container for holding a transparent material sample, disposed on the transparent substrate; a pair of electrodes disposed on the container for connecting an external measurement circuit to perform a two-electrode method measurement; the optical path of at least one set of optical probes is configured to detect the transparent material sample inside the container; a metal reflective film is disposed at the interface between the transparent substrate and the container, or directly disposed on the side surface of the transparent substrate facing the container.

[0097] The transparent substrate, made of quartz or sapphire, is a support structure with optical transparency. Its function is to provide a light path for the optical probe to perform optical detection of the sample. The container, made of transparent polymer or glass, is a sealed space for fixing the transparent sample. Its function is to maintain sample stability and prevent external interference during impact loading. A pair of electrodes, made of platinum or gold thin films deposited on the container surface, are conductive components for conducting current. They connect to external measurement circuitry to obtain the sample's total conductivity data. The optical probe, made of fiber optic bundles combined with a laser and photodetector, is used to analyze the sample's electronic conductivity by reflecting light signals. The metal reflective film, a highly reflective layer on the transparent substrate, is formed using aluminum or silver thin films through vacuum evaporation. Its function is to enhance the intensity of reflected light at the back interface to improve optical measurement accuracy.

[0098] Understandably, the transparent substrate acts as an optical window, allowing probe light to penetrate to the sample surface. The container holds the sample in a predetermined position to withstand impact loading. Electrodes are connected to external circuitry to form a closed loop, triggering a switch to conduct the circuit before the shock wave arrives. The total conductivity of the sample is calculated by monitoring voltage changes. The fiber optic end face of the optical probe is aligned parallel to the front and rear interfaces of the container. After partial reflection at the front interface, the remaining portion of the probe light penetrates the sample and is reflected back by a metal reflective film at the rear interface. The electronic conductivity of the sample is derived by analyzing changes in the intensity of the reflected light. The metal reflective film significantly improves the signal-to-noise ratio of the optical signal by increasing the reflectivity of the rear interface, maintaining effective detection even when the optical properties of the sample deteriorate due to impact compression.

[0099] Compared to existing technologies, traditional measurement devices typically employ single-electrode methods or step-by-step optical measurements, making it impossible to simultaneously acquire total conductivity and electronic conductivity data during impact events. This solution integrates electrodes and optical probes, enabling simultaneous execution of electrical measurements and optical reflection methods under the same spatiotemporal conditions, avoiding the operational differences caused by step-by-step experiments. The introduction of a metallic reflective film solves the signal attenuation problem caused by the decrease in interfacial reflectivity of transparent materials under high pressure, while the combined design of the transparent substrate and container addresses both mechanical support and optical detection requirements.

[0100] Through the above technical solution, this application can simultaneously acquire total conductivity and electronic conductivity data during a single impact loading process, eliminating systematic errors introduced by step-by-step measurements and providing a reliable experimental basis for studying the dynamic conductivity behavior of materials under extreme conditions. The metal reflective film effectively enhances the detection capability of weak reflection signals, ensuring the accuracy of optical measurement results under high-pressure environments. The spatial arrangement design of the electrodes and optical probe avoids mutual interference of signals, ensuring the independence and synchronization of the two types of measurement data.

[0101] This application further proposes an optical probe including an incident optical fiber and a receiving optical fiber, wherein the incident optical fiber is used to guide the probe light to the front and / or rear interface of the container, and the receiving optical fiber is used to receive reflected light from the corresponding interface.

[0102] The incident fiber refers to the optical transmission device used to transmit probe light to the interface under test. It can be implemented using multimode or single-mode fiber, and its core diameter can be adjusted according to the spot size. The receiving fiber is the optical element used to collect the reflected light signal. It can be a fiber bundle arranged symmetrically with the incident fiber, spatially separating the incident and reflected light paths to avoid crosstalk. This separation design of the incident and receiving fibers achieves optical path isolation, preventing the reflected signal from being interfered with by the incident light, thereby improving the signal-to-noise ratio.

[0103] Understandably, the end of the incident optical fiber is fixed to the optical probe holder, and its exit end face maintains a preset distance from the front or rear interface of the container, allowing the probe light to be incident on the interface under test at a specific angle. The receiving optical fiber is arranged around the incident optical fiber, with its receiving end face forming an angle with the incident optical axis, used to capture reflected light from the interface under test. During the impact loading process, the incident optical fiber transmits the probe light generated by the pulsed laser to the surface of the transparent material sample, and the reflected light is transmitted through the receiving optical fiber to the photodetector, thereby achieving dynamic measurement of reflectivity. This structure eliminates stray light interference by physically isolating the incident and reflected light paths, while the flexible connection characteristics of the optical fiber allow the probe to be placed away from the impact area, avoiding the impact of mechanical impact on the optical system.

[0104] Compared to existing technologies, traditional optical reflection measurements typically employ free-space optical paths or shared fiber transmission, which are prone to optical path shifts or signal attenuation due to vibrations. This solution, however, maintains optical path stability during shock wave propagation by independently arranging the incident and receiving fibers. Furthermore, the small size of the fibers reduces their space requirement on the measurement target structure, enabling simultaneous detection at multiple locations. In addition, the angle design of the fiber end faces optimizes reflected light collection efficiency; for example, using tilted end faces allows the receiving fiber to effectively capture low-intensity reflected signals.

[0105] Through the above technical solution, this application can achieve high-precision acquisition of reflected light from the material interface during impact compression, improve signal transmission stability through fiber optic separation design, ensure the real-time performance and reliability of electronic conductivity measurement data, and avoid interference of the measuring device on the propagation path of the shock wave.

[0106] This application further proposes a transient conductivity measurement target connected to an external measurement circuit, which includes a power supply, a switch, a reference resistor, and a protection resistor; the switch is configured to turn on in response to a trigger signal before the shock wave reaches the transparent material sample.

[0107] In this circuit, a switch is an electronic component that controls the on / off state of the circuit. It can be implemented using relays or semiconductor switching elements. Its function is to precisely control the start-up timing of the measurement circuit based on a trigger signal, ensuring strict synchronization between conductivity measurement and the shock wave loading process. A power supply is a device that provides stable voltage or current to the measurement circuit. It can be implemented using a DC regulated power supply or a pulse power supply, and its output parameters must match the resistance characteristics of the material under test. A reference resistor is a known resistance element used to construct a voltage divider or current divider measurement network. It can be implemented using a precision metal film resistor or a wire-wound resistor, and its resistance range must cover the expected resistance change range of the transparent material under impact compression. A protection resistor is a current-limiting element connected in series in the circuit. It can be implemented using a power resistor or a variable resistor, and its resistance value must be greater than that of the reference resistor and the transparent material sample. It is used to prevent damage to the measurement circuit due to transient overcurrent.

[0108] Understandably, when the shock wave generator is activated, a trigger signal is sent to the switch control terminal within a preset time interval before the shock wave propagates to the transparent material sample, causing the switch to immediately close and activate the measurement circuit. At this time, the current output from the power supply flows through a series circuit consisting of a reference resistor, a protective resistor, and the transparent material sample. By measuring the voltage change across the reference resistor, the dynamic resistance value of the transparent material sample can be calculated in real time. This trigger timing design ensures that the start time of conductivity measurement is strictly earlier than the loading process of the shock wave onto the sample, thereby completely capturing the continuous conductivity change data of the material from its initial state to its impact-compressed state.

[0109] In some specific implementations, the switch can be positioned between the power output terminal and the reference resistor, controlling the circuit's on / off state by cutting off the main power supply circuit. Alternatively, the switch can be directly integrated into the measurement circuit consisting of a pair of electrodes, controlling the current path via a bypass method.

[0110] Compared to existing technologies, traditional impact loading experiments typically involve the measurement circuit being manually or passively triggered only after the shock wave reaches the sample, making it impossible to record the initial conductivity change of the material at the moment of impact. This proposed solution, through an active triggering mechanism precisely matched to the shock wave propagation timing, achieves pre-conduction of the measurement circuit before the shock wave arrives, eliminating the data loss problem caused by circuit delays in traditional methods.

[0111] Through the above technical solution, this application effectively solves the problem that the starting time of conductivity measurement during impact loading lags behind the material state change, ensuring that the total conductivity measurement data and the electronic conductivity data measured by optical reflection method are strictly aligned on the time axis, providing a complete and synchronous test data basis for analyzing the dynamic conductivity behavior of materials under extreme conditions.

[0112] This application further proposes that the switch be located at the power output terminal or in a circuit consisting of a pair of electrodes.

[0113] The switch, in this context, refers to an electronic component used to control the on / off state of the circuit. It can be implemented using an electromagnetic relay or a semiconductor switching device. Its function is to quickly close upon receiving a trigger signal, ensuring that the measurement circuit is conductive before the shock wave reaches the transparent material sample. The power output terminal or the loop formed by the electrodes refers to two optional installation positions of the switch in the circuit. Specifically, it can be placed at the output port where the power supply connects to the external measurement circuit, or directly integrated into the current loop formed by the electrodes and the sample. This design reduces measurement errors by shortening the path of interference signals.

[0114] Understandably, when the switch is in the power output position, the connection between the power supply and the external measurement circuit is disconnected, and conduction only occurs when the trigger signal arrives, preventing interference current from being generated in the circuit before the impact loading. When the switch is in the electrode circuit, the current path between the electrode and the sample is directly controlled, ensuring that the current flows only through the sample area at the moment the shock wave arrives. The two settings can be selected according to experimental needs. For example, the power output setting should be preferred in scenarios where power supply noise needs to be avoided, while the electrode circuit setting should be used in scenarios where precise control of the sample current is required.

[0115] Compared with existing technologies, traditional measuring devices usually fix the switch in a single position, such as only on the power supply side or the load side, which results in an excessively long signal transmission path or the introduction of interference sources. However, this application effectively shortens the critical signal path and reduces the impact of electromagnetic interference on measurement accuracy by flexibly selecting the switch position.

[0116] Through the above technical solution, this application resolves the contradiction between the timing of circuit conduction and signal interference during the impact loading process, ensuring that the total conductivity measurement and the impact loading process are strictly synchronized, while reducing the interference of stray current on the optical measurement data of electronic conductivity, thereby improving the time matching and accuracy of the two measurement data.

[0117] In some embodiments,

[0118] It is worth noting that this application can measure the total conductivity and electronic conductivity of liquids with high time resolution. The experiment uses optical methods to measure electronic conductivity in response to AC conductivity, eliminating the influence of this measurement on the total conductivity measurement. Simultaneously, a two-electrode method is used to measure DC conductivity; this method only causes ion enrichment and has minimal impact on electronic conductivity measurement. It can be used in other similar products; the switch does not need to be located at the power supply, but can be located at the circuit under test or control the power switch. The detection system does not necessarily detect the voltage across the circuit segment under test, but can detect the actual current flowing through the branch of the circuit under test. The light does not need to be monochromatic; it can be light within a certain wavelength range.

[0119] In summary, this application utilizes a two-electrode method to measure DC conductivity and an optical method to measure AC conductivity to measure the total conductivity and electronic conductivity in an impact-transparent material target. In this method, the two-electrode method only affects ion distribution and has little impact on electrons, while the optical measurement, as a detection method, is completely decoupled from the two-electrode method in terms of time and area of ​​action. This measurement method offers high time resolution, and both conductivity measurements are effective without interference.

[0120] The technical solutions provided in this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the system and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for measuring the transient conductivity of a transparent material under impact compression, characterized in that, The method is applied to a transient conductivity measurement target, the transient conductivity measurement target comprising a container holding a transparent material sample, a pair of electrodes disposed on the container, and at least one set of optical probes for optical detection; the method includes: A transparent material sample in the transient conductivity measurement target is loaded using a shock wave; During the impact loading process, the following operations are performed simultaneously: The total conductivity of the transparent material sample was measured using the two-electrode method through the pair of electrodes. The electronic conductivity of the transparent material sample is measured using the optical reflection method through at least one set of optical probes.

2. The method according to claim 1, characterized in that, The method of measuring the total conductivity of the transparent material sample using the two-electrode method includes: Construct a measurement circuit, which includes a power supply, a test branch connected to the pair of electrodes, a reference resistor branch, and a protection resistor; A trigger signal is received just before the shock wave reaches the transparent material sample to close the switch in the measurement circuit, thereby turning on the measurement circuit. Monitor the voltage change of the branch under test or the reference resistor branch; The resistance value of the transparent material sample is calculated based on the voltage change, and the total conductivity is obtained from the resistance value.

3. The method according to claim 2, characterized in that, The resistance value of the protective resistor is greater than the resistance value of the reference resistor and the resistance value of the transparent material sample under impact compression.

4. The method according to claim 1, characterized in that, The method of measuring the electronic conductivity of the transparent material sample using optical reflection includes: The optical probe emits detection light toward the transparent material sample; Receive reflected light signals from the front and back interfaces of the transparent material sample; The reflectivity of the transparent material sample is determined based on the reflected light signal; Based on the reflectivity, the AC conductivity of the transparent material sample in the optical frequency band is calculated to determine the AC conductivity as electronic conductivity.

5. The method according to claim 4, characterized in that, Based on the reflectivity, the AC conductivity of the transparent material sample in the optical frequency band is calculated: The complex refractive index of the transparent material sample is calculated based on the reflectivity. Based on the calculation formulas for the complex refractive index and complex dielectric constant, the complex dielectric constant is obtained; Based on the calculation formulas for the complex permittivity and AC conductivity, the AC conductivity of the optical frequency band is calculated.

6. The method according to claim 4, characterized in that, The rear interface is provided with a metal reflective film to enhance the reflected light signal; the thickness of the metal reflective film is 100 nanometers to 1 micrometer.

7. A transient conductivity measuring target, characterized in that, include: Transparent substrate; A container for holding a transparent material sample is disposed on the transparent substrate; A pair of electrodes is disposed on the container for connecting an external measurement circuit to perform two-electrode measurement. At least one set of optical probes, the optical path of which is configured to detect transparent material samples inside the container; A metal reflective film is disposed at the interface between the transparent substrate and the container, or directly disposed on the surface of the transparent substrate facing the container. The transient conductivity measuring target is used to implement the method for measuring the transient conductivity of transparent materials under impact compression as described in any one of claims 1-6.

8. The transient conductivity measuring target according to claim 7, characterized in that, The optical probe includes an incident optical fiber and a receiving optical fiber. The incident optical fiber is used to guide the probe light to the front and / or rear interface of the container, and the receiving optical fiber is used to receive reflected light from the corresponding interface.

9. The transient conductivity measuring target according to claim 7, characterized in that, The transient conductivity measurement target is connected to an external measurement circuit, which includes a power supply, a switch, a reference resistor, and a protection resistor. The switch is configured to turn on in response to a trigger signal before the shock wave reaches the transparent material sample.

10. The transient conductivity measuring target according to claim 9, characterized in that, The switch is located at the power output terminal or in the circuit formed by the pair of electrodes.

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