Interface electron excitation spectrum generation method based on time domain and frequency laminated scanning

Abstract

The invention provides an interface electron excitation spectrum generation method based on time domain and frequency lamination scanning. The method can be applied to the technical field of nonlinear optics and interface microstructures. The interface electron excitation spectrum generation method based on time domain and frequency laminated scanning comprises the steps that in response to an interface electron excitation spectrum generation request, a first laser pulse and a second laser pulse are obtained, the first laser pulse is used for resonance excitation of a sample, and the second laser pulse is used for non-resonance excitation of the sample; generating N electron sum frequency spectrums according to the first laser pulse and the second laser pulse, N being an integer greater than or equal to 1; and carrying out iterative processing on the N electron sum frequency spectrums to obtain an interface electron excitation spectrum.

Description

Technical Field

[0001] The present disclosure relates to the technical field of nonlinear optics and interface microstructure, and in particular to a method, device, equipment, medium and program product for generating an interface electron excitation spectrum based on time domain and frequency stack scanning. Background Art

[0002] The key to understanding interface physics and chemistry at the molecular level is to accurately measure the interface molecular structure, intermolecular interactions, and electron and energy transfer dynamics in real time. Interface electron excitation spectroscopy can be used to characterize the complex system of interfaces in real environments.

[0003] In the process of realizing the concept of the present disclosure, the inventors found that the related technology mainly uses a narrowband laser pulse to achieve frequency up-conversion of the polarization field generated by another broadband laser pulse. Since the bandwidth of the laser pulse determines the frequency resolution, and the bandwidth of the broadband laser pulse is wider, resulting in a lower frequency resolution, the spectrum narrowing performed to achieve high frequency resolution of the interface electron excitation spectrum will lead to the loss of up-conversion light power, greatly reducing the signal-to-noise ratio of the interface electron excitation spectrum, and it is also impossible to obtain the phase information of the interface electron excitation spectrum. Summary of the invention

[0004] In view of the above problems, the present disclosure provides a method, device, equipment, medium and program product for generating an interface electron excitation spectrum based on time domain and frequency stack scanning.

[0005] According to a first aspect of the present disclosure, a method for generating an interface electron excitation spectrum based on time domain and frequency stack scanning is provided, comprising: in response to a request for generating an interface electron excitation spectrum, acquiring a first laser pulse and a second laser pulse, wherein the first laser pulse is used for resonant excitation of a sample, and the second laser pulse is used for non-resonant excitation of the sample; generating N electron and frequency spectra according to the first laser pulse and the second laser pulse, wherein N is an integer greater than or equal to 1; and iteratively processing the N electron and frequency spectra to obtain an interface electron excitation spectrum.

[0006] According to an embodiment of the present disclosure, generating N electron and frequency spectra based on the first laser pulse and the second laser pulse includes: determining N time delays between the first laser pulse and the second laser pulse; and generating electron and frequency spectra of each of the N time delays based on the N time delays.

[0007] According to an embodiment of the present disclosure, the above-mentioned determination of the N time delays between the above-mentioned first laser pulse and the above-mentioned second laser pulse includes: scanning the above-mentioned first laser pulse and the above-mentioned second laser pulse at a preset time interval to obtain the above-mentioned N time delays, wherein the above-mentioned preset time interval is smaller than the pulse width of the above-mentioned second laser pulse.

[0008] According to an embodiment of the present disclosure, the above-mentioned N time delays are used to generate respective electron sum-frequency spectra, including: based on the above-mentioned N time delays, according to the above-mentioned first laser pulse and the above-mentioned second laser pulse, N electron sum-frequency signals are generated; according to the above-mentioned N electron sum-frequency signals, electron sum-frequency spectra of the N time delays are generated.

[0009] According to an embodiment of the present disclosure, the above-mentioned N electron sum-frequency spectra are iteratively processed to obtain an interface electron excitation spectrum, including: determining the time domain distribution of the above-mentioned electron sum-frequency signal according to the up-conversion pulse field distribution and the function to be measured, wherein the above-mentioned up-conversion pulse field distribution is determined by the above-mentioned second laser pulse; performing Fourier transform on the time domain distribution of the above-mentioned electron sum-frequency signal to obtain the frequency domain distribution of the above-mentioned electron sum-frequency signal; obtaining frequency domain components according to the frequency domain distribution of the above-mentioned electron sum-frequency signal and the N electron sum-frequency spectra; updating the above-mentioned function to be measured based on the above-mentioned frequency domain components, the frequency domain distribution of the above-mentioned electron sum-frequency signal, the above-mentioned up-conversion pulse field distribution and preset parameters to obtain a target function to be measured; performing Fourier transform on the above-mentioned target function to be measured to obtain the above-mentioned interface electron excitation spectrum.

[0010] According to an embodiment of the present disclosure, the above-mentioned function to be measured is updated based on the frequency domain distribution of the above-mentioned electronic and frequency signals to obtain the target function to be measured, including: performing an inverse Fourier transform on the above-mentioned frequency domain components to obtain time domain components; obtaining the above-mentioned target function to be measured based on the above-mentioned time domain components, the time domain distribution of the above-mentioned electronic and frequency signals, the above-mentioned up-conversion pulse field distribution and preset parameters.

[0011] According to an embodiment of the present disclosure, the frequency domain component is obtained according to the frequency domain distribution of the electronic sum-frequency signal, including: determining the phase of the electronic sum-frequency signal according to the frequency domain distribution of the electronic sum-frequency signal; and obtaining the frequency domain component according to the phase of the electronic sum-frequency signal and the N electronic sum-frequency spectra.

[0012] A second aspect of the present disclosure provides an interface electron excitation spectrum generation device based on time domain and frequency stack scanning, comprising: an acquisition module, a generation module and a obtaining module.

[0013] The acquisition module is used to acquire a first laser pulse and a second laser pulse in response to a request for generating an interface electron excitation spectrum, wherein the first laser pulse is used for resonant excitation of the sample, and the second laser pulse is used for non-resonant excitation of the sample.

[0014] A generating module is used to generate an electronic sum frequency spectrum according to the first laser pulse and the second laser pulse.

[0015] The module is used to iteratively process the N electronic sum-frequency spectra to obtain the interface electronic excitation spectrum.

[0016] A third aspect of the present disclosure provides an electronic device, comprising: one or more processors; and a memory for storing one or more computer programs, wherein the one or more processors execute the one or more computer programs to implement the steps of the above method.

[0017] The fourth aspect of the present disclosure further provides a computer-readable storage medium having a computer program or instructions stored thereon, which implements the steps of the above method when the above computer program or instructions are executed by a processor.

[0018] The fifth aspect of the present disclosure further provides a computer program product, including a computer program or instructions, which implement the steps of the above method when the above computer program or instructions are executed by a processor.

[0019] According to the method, device, electronic device, medium and program product for generating an interface electron excitation spectrum based on time domain and frequency stack scanning provided by the present disclosure, N electron sum frequency spectra can be generated according to the acquired first laser pulse and second laser pulse, and then the N electron sum frequency spectra are iteratively processed to obtain an interface electron excitation spectrum with high frequency resolution. In this process, sacrificing the intensity of the up-conversion light can be avoided, thereby achieving a higher signal-to-noise ratio while ensuring that the interface electron excitation spectrum has a higher frequency resolution, and at the same time, the interface electron excitation spectrum carries phase information. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] 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:

[0021] Figure 1 A schematic diagram showing an application scenario of a method for generating an interface electron excitation spectrum based on time domain and frequency stack scanning according to an embodiment of the present disclosure;

[0022] Figure 2 The flowchart of the method for generating the interface electron excitation spectrum based on time domain and frequency stack scanning according to the embodiment of the present disclosure is schematically shown;

[0023] Figure 3 A flow chart of a method for generating an interface electron excitation spectrum based on time domain and frequency stack scanning according to another embodiment of the present disclosure is schematically shown;

[0024] Figure 4 Schematically shows an optical path diagram of interface electron excitation spectroscopy based on time domain and frequency stack scanning according to an embodiment of the present disclosure;

[0025] Figure 5 Schematically showing the intensity distribution diagram of the electronic sum frequency signal under different time delays according to an embodiment of the present disclosure;

[0026] Figure 6 A block diagram schematically shows a structure of a device for generating an interface electron excitation spectrum based on time domain and frequency stack scanning according to an embodiment of the present disclosure; and

[0027] Figure 7 A block diagram of an electronic device suitable for implementing a method for generating an interface electron excitation spectrum based on time domain and frequency stack scanning according to an embodiment of the present disclosure is schematically shown. DETAILED DESCRIPTION

[0028] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present disclosure. In the following detailed description, 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 known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0029] 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 existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0030] All terms (including technical and scientific terms) used herein 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.

[0031] When using expressions such as "at least one of A, B, and C, etc.", they should generally be interpreted according to the meaning of the expression 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.).

[0032] In the technical solution of the present disclosure, the user information (including but not limited to user personal information, user image information, user device information, such as location information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved are all information and data authorized by the user or fully authorized by all parties, and the collection, storage, use, processing, transmission, provision, disclosure and application of the relevant data comply with relevant laws, regulations and standards, take necessary confidentiality measures, do not violate public order and good morals, and provide corresponding operation entrances for users to choose to authorize or refuse.

[0033] Accurate detection of the interface electronic state structure and interface electronic dynamics is an important way to understand microscopic processes and mechanisms such as interface photoelectric conversion and chemical reactions. Based on even-order nonlinear optical response, electronic sum frequency spectroscopy can effectively suppress the interference of bulk signals and obtain interface microstructure information when studying materials with central inversion symmetry. When light irradiates the interface of a material, the energy of the photon is absorbed by the electrons at the interface, causing the electrons to transition from the ground state to the excited state, thereby generating electronic excitation. In this process, there are phenomena such as light absorption, light emission or light scattering. Interface electronic excitation spectroscopy is to obtain information such as electronic structure, energy level distribution and electronic transition at the interface by measuring the spectral signals generated by the interaction between these light and matter. Therefore, in the field of research on interface microstructure dynamics, interface electronic excitation spectroscopy can play a greater role.

[0034] In the process of realizing the present disclosure, it is found that in the related art, a narrow-band laser is mainly used to achieve frequency up-conversion of the polarization field generated by another broadband pulse, and the bandwidth of the narrow-band laser pulse determines the frequency resolution. However, the spectrum narrowing performed to achieve high frequency resolution of the interface electron excitation spectrum will lead to a very considerable loss of up-conversion light power, greatly reducing the measurement signal-to-noise ratio, and at the same time, it is impossible to obtain the phase information of the interface electron excitation spectrum.

[0035] In view of this, an embodiment of the present disclosure provides a method for generating an interface electron excitation spectrum based on time domain and frequency stack scanning, comprising: in response to a request for generating an interface electron excitation spectrum, acquiring a first laser pulse and a second laser pulse, wherein the first laser pulse is used for resonant excitation of the sample, and the second laser pulse is used for non-resonant excitation of the sample; generating N electron and frequency spectra according to the first laser pulse and the second laser pulse, wherein N is an integer greater than or equal to 1; and iteratively processing the N electron and frequency spectra to obtain an interface electron excitation spectrum.

[0036] Figure 1 The application scenario diagram of the interface electron excitation spectrum generation based on time domain and frequency stack scanning according to an embodiment of the present disclosure is schematically shown.

[0037] like Figure 1 As shown, the application scenario 100 according to this embodiment may include a first terminal device 101, a second terminal device 102, a third terminal device 103, a network 104, and a server 105. The network 104 is used to provide a medium for a communication link between the first terminal device 101, the second terminal device 102, the third terminal device 103, and the server 105. The network 104 may include various connection types, such as wired, wireless communication links, or optical fiber cables, etc.

[0038] The user can use the first terminal device 101 , the second terminal device 102 , and the third terminal device 103 to interact with the server 105 through the network 104 to receive or send messages, etc.

[0039] The first terminal device 101, the second terminal device 102, and the third terminal device 103 may be various electronic devices having display screens and supporting web browsing, including but not limited to smart phones, tablet computers, laptop computers, desktop computers, and the like.

[0040] The server 105 may be a server that provides various services, such as a background management server (only as an example) that provides support for websites browsed by users using the first terminal device 101, the second terminal device 102, and the third terminal device 103. The background management server may analyze and process the received data such as user requests, and feed back the processing results (such as web pages, information, or data obtained or generated according to user requests) to the terminal device.

[0041] It should be noted that the interface electron excitation spectrum generation method based on time domain and frequency stacking scanning provided in the embodiment of the present disclosure can generally be executed by the server 105. Accordingly, the interface electron excitation spectrum generation device based on time domain and frequency stacking scanning provided in the embodiment of the present disclosure can generally be set in the server 105. The interface electron excitation spectrum generation method based on time domain and frequency stacking scanning provided in the embodiment of the present disclosure can also be executed by a server or server cluster that is different from the server 105 and can communicate with the first terminal device 101, the second terminal device 102, the third terminal device 103 and / or the server 105. Accordingly, the interface electron excitation spectrum generation device based on time domain and frequency stacking scanning provided in the embodiment of the present disclosure can also be set in a server or server cluster that is different from the server 105 and can communicate with the first terminal device 101, the second terminal device 102, the third terminal device 103 and / or the server 105.

[0042] It should be understood that Figure 1 The number of the first terminal device, the second terminal device, the third terminal device, the network and the server in the embodiment is only for illustration. According to the implementation requirements, there may be any number of the first terminal device, the second terminal device, the third terminal device, the network and the server.

[0043] The following will be based on Figure 1 The scene described by Figure 2~Figure 5 The method for generating an interface electron excitation spectrum based on time domain and frequency stack scanning in the disclosed embodiment is described in detail.

[0044] Figure 2 The flowchart of the method for generating interface electron excitation spectrum based on time domain and frequency stack scanning according to an embodiment of the present disclosure is schematically shown.

[0045] like Figure 2 As shown, the method 200 for generating an interface electron excitation spectrum based on time domain and frequency stack scanning of this embodiment includes operations S210 to S230.

[0046] In operation S210 , in response to an interface electron excitation spectrum generation request, a first laser pulse and a second laser pulse are acquired.

[0047] In operation S220, N electron sum frequency spectra are generated according to the first laser pulse and the second laser pulse.

[0048] In operation S230, N electron sum frequency spectra are iteratively processed to obtain an interface electron excitation spectrum.

[0049] According to the embodiments of the present disclosure, the interface electron excitation spectrum can characterize the spectrum generated by the energy level transition of electrons on the interface due to the absorption of light energy. The interface electron excitation spectrum can provide information about the electronic structure, chemical state and interaction of the material interface. The interface electron excitation spectrum is based on the even-order nonlinear optical response. When targeting materials with central inversion symmetry, it can effectively suppress the interference of the bulk phase signal and obtain the interface microstructure information.

[0050] According to an embodiment of the present disclosure, the first laser pulse can be used for resonant excitation of the sample, and the second laser pulse can be used for non-resonant excitation of the sample. The second laser pulse can be a broadband laser, or the second laser pulse can be used as up-conversion light, that is, a broadband laser can be used as up-conversion light. For example, the first laser pulse can be a visible or infrared ultrashort laser pulse with a wavelength of 600nm to 850nm, and the second laser pulse can be a short infrared laser pulse with a wavelength of 1750nm to 2300nm.

[0051] According to an embodiment of the present disclosure, an electron sum frequency spectrum can characterize that two different laser pulses overlap at a sample, and a beam of light of a new wavelength is generated at the sample due to an even-order nonlinear optical effect. The first laser pulse and the second laser pulse can excite the sample at different time points, that is, there are multiple time delays between the first laser pulse and the second laser pulse. Thus, N electron sum frequency spectra can be generated based on the first laser pulse and the second laser pulse, where N is an integer greater than or equal to 1. For example, 10 electron sum frequency spectra can be generated.

[0052] According to an embodiment of the present disclosure, by iteratively processing N electron sum frequency spectra, that is, iterating multiple electron sum frequency spectra with lower frequency resolutions, an interface electron excitation spectrum with higher frequency resolution and carrying phase information can be obtained.

[0053] According to an embodiment of the present disclosure, N electron-electron sum-frequency spectra can be generated based on the acquired first laser pulse and second laser pulse, and then the N electron-electron sum-frequency spectra are iteratively processed to obtain an interface electron excitation spectrum with high frequency resolution. In this process, sacrificing the intensity of the up-conversion light can be avoided, thereby achieving a higher signal-to-noise ratio while ensuring that the interface electron excitation spectrum has a higher frequency resolution. At the same time, the interface electron excitation spectrum carries phase information.

[0054] According to an embodiment of the present disclosure, N electron sum frequency spectra are generated according to a first laser pulse and a second laser pulse, including: determining N time delays between the first laser pulse and the second laser pulse; and generating electron sum frequency spectra of the N time delays, respectively, according to the N time delays.

[0055] According to an embodiment of the present disclosure, the movement of the electric translation stage can change the optical path of the laser pulse, thereby changing the time delay between the first laser pulse and the second laser pulse. After each movement of the electric translation stage is completed, the first laser pulse and the second laser pulse are scanned using the electric translation stage so that the time delay corresponding to the movement can be determined. By moving the electric translation stage N times, N time delays can be determined.

[0056] According to an embodiment of the present disclosure, a first laser pulse resonantly excites a sample, and a second laser pulse non-resonantly excites a sample. For each time delay, an electron sum frequency signal corresponding to the time delay can be generated based on the first laser pulse and the second laser pulse. The electron sum frequency signal is measured by a spectrometer to generate an electron sum frequency spectrum corresponding to the time delay, so that for N time delays, electron sum frequency spectra of each of the N time delays can be generated.

[0057] According to an embodiment of the present disclosure, by scanning the time delay between the first laser pulse and the second laser pulse, N time delays can be determined, and when the N time delays are determined, the first laser pulse and the second laser pulse excite the sample to generate electron sum-frequency spectra for each of the N time delays, thereby increasing the intensity of the electron sum-frequency signal, thereby increasing the frequency resolution of the interface electron excitation spectrum while carrying phase information.

[0058] According to an embodiment of the present disclosure, determining N time delays between a first laser pulse and a second laser pulse includes: scanning the first laser pulse and the second laser pulse at a preset time interval to obtain the N time delays.

[0059] According to an embodiment of the present disclosure, the preset time interval may represent the time interval between scanning the first laser pulse and scanning the second laser pulse. The second laser pulse is used as up-converted light, and the preset time interval may be less than the pulse width of the second laser pulse. For example, when the pulse width of the second laser pulse is 100 fs, the preset time interval may be an interval less than 100 fs, for example, the preset time interval is 50 fs.

[0060] According to an embodiment of the present disclosure, a first laser pulse and a second laser pulse are scanned at a preset time interval using an electric translation stage, and N time delays can be determined. When the preset time interval is less than the pulse width of the second laser pulse, redundant information can be generated, so that the interface electron excitation spectrum can be obtained using a time domain stack scanning iterative algorithm.

[0061] According to an embodiment of the present disclosure, by scanning the first laser pulse and the second laser pulse at a preset time interval, N time delays can be determined. Since the preset time interval is smaller than the time delay, redundant information can be generated, thereby improving the accuracy of the obtained interface electron excitation spectrum.

[0062] According to an embodiment of the present disclosure, electron sum-frequency spectra of the N time delays are generated according to N time delays, including: based on the N time delays, N electron sum-frequency signals are generated according to the first laser pulse and the second laser pulse; and electron sum-frequency spectra of the N time delays are generated according to the N electron sum-frequency signals.

[0063] According to an embodiment of the present disclosure, a first laser pulse and a second laser pulse excite a sample, and based on N time delays, an electronic sum frequency signal corresponding to the N time delays can be generated based on the first laser pulse and the second laser pulse.

[0064] According to an embodiment of the present disclosure, N electron sum frequency signals are measured by a spectrometer to generate N electron sum frequency spectra with respective time delays.

[0065] According to an embodiment of the present disclosure, when N time delays are determined, N electron sum frequency signals can be generated based on the first laser pulse and the second laser pulse, thereby generating electron sum frequency spectra for each of the N time delays, thereby improving the intensity of the electron sum frequency signal and thereby improving the signal-to-noise ratio of the electron sum frequency spectrum.

[0066] Figure 3 The flowchart of a method for generating an interface electron excitation spectrum based on time domain and frequency stack scanning according to yet another embodiment of the present disclosure is schematically shown.

[0067] like Figure 3 As shown, the method 300 for generating an interface electron excitation spectrum based on time domain and frequency stack scanning includes operations S310 to S350.

[0068] In operation S310 , in response to an interface electron excitation spectrum generation request, a first laser pulse and a second laser pulse are acquired.

[0069] In operation S320, the first laser pulse and the second laser pulse are scanned at a preset time interval to obtain N time delays.

[0070] In operation S330, N electrical sum frequency signals are generated according to the first laser pulse and the second laser pulse based on the N time delays.

[0071] In operation S340, N time-delayed respective electron sum frequency spectra are generated according to the N electron sum frequency signals.

[0072] In operation S350, N electron sum frequency spectra are iteratively processed to obtain an interface electron excitation spectrum.

[0073] According to the embodiments of the present disclosure, N electronic sum frequency spectra can be processed by a time domain stack scanning iterative algorithm to obtain an interface electron excitation spectrum. This process is described in detail below.

[0074] According to an embodiment of the present disclosure, N electron sum frequency spectra are iteratively processed to obtain an interface electron excitation spectrum, including: determining the time domain distribution of the electron sum frequency signal based on the up-conversion pulse field distribution and the function to be measured; performing Fourier transform on the time domain distribution of the electron sum frequency signal to obtain the frequency domain distribution of the electron sum frequency signal; obtaining the frequency domain component based on the frequency domain distribution of the electron sum frequency signal and N electron sum frequency spectra; updating the function to be measured based on the frequency domain component, the frequency domain distribution of the electron sum frequency signal, the up-conversion light pulse field distribution and preset parameters to obtain a target function to be measured; performing Fourier transform on the target function to be measured to obtain an interface electron excitation spectrum.

[0075] According to an embodiment of the present disclosure, the up-conversion pulse field distribution can be determined by a second laser pulse that non-resonantly excites the sample, and further, the up-conversion pulse field distribution can be determined by the frequency-resolved optical gating (FROG) experimental characterization results of the second laser pulse. The time domain distribution of the electronic sum frequency signal can be determined based on the up-conversion pulse field distribution and the function to be measured, as shown in the following formula (1).

[0076] (1)

[0077] in, represents the time domain distribution of the electronic sum-frequency signal, represents the function to be tested, represents the upconversion pulse field distribution, represents the jth time delay, n represents the number of iterations, represents the i-th moment.

[0078] According to the embodiments of the present disclosure, the time domain distribution of the electronic sum-frequency signal can be Fourier transformed, so that the frequency domain distribution of the electronic sum-frequency signal can be obtained. .

[0079] According to an embodiment of the present disclosure, the modulus of the frequency domain distribution of the electronic sum frequency signal may be replaced by the square root of the electronic sum frequency spectrum. The frequency domain component may be obtained according to the frequency domain distribution of the electronic sum frequency signal and N electronic sum frequency spectra, including: the phase of the electronic sum frequency signal may be determined according to the frequency domain distribution of the electronic sum frequency signal, and then the frequency domain component may be obtained according to the phase of the electronic sum frequency signal and N electronic sum frequency spectra, as shown in the following formula (2).

[0080] (2)

[0081] in, represents the frequency domain component, Represents the electronic sum-frequency spectrum.

[0082] According to an embodiment of the present disclosure, the N electronic sum frequency spectra may be processed using the above formula (2) respectively, thereby obtaining frequency domain components corresponding to the N electronic sum frequency spectra.

[0083] According to an embodiment of the present disclosure, based on frequency domain components, frequency domain distribution of electronic and frequency signals, up-conversion pulse field distribution and preset parameters, the function to be measured is updated to obtain a target function to be measured, including: performing an inverse Fourier transform on the frequency domain components to obtain time domain components; obtaining the target function to be measured according to the time domain components, time domain distribution of electronic and frequency signals, up-conversion pulse field distribution and preset parameters.

[0084] According to an embodiment of the present disclosure, a time domain component may be obtained by performing an inverse Fourier transform on a frequency domain component.

[0085] According to the embodiments of the present disclosure, the target function to be measured can be obtained according to the time domain component, the time domain distribution of the electronic sum frequency signal, the up-conversion pulse field distribution and the preset parameters, as shown in the following formula (3).

[0086] (3)

[0087] in, It represents the new function to be tested after the function to be tested is iterated once. represents the first coefficient, represents the second coefficient, represents the transpose of the upconversion pulse field distribution.

[0088] According to an embodiment of the present disclosure, the first coefficient and the second coefficient are both constants, for example, , The first coefficient depends mainly on the noise level, the second coefficient depends on the pulse width and the time delay of the second laser pulse.

[0089] According to an embodiment of the present disclosure, the function to be measured can be updated based on the frequency domain distribution of the electronic and frequency signals. By updating the function to be measured, the target function to be measured can be further approached. When the number of iterations reaches a preset number of iterations or the new function to be measured after iteration converges, the target function to be measured can be obtained.

[0090] According to an embodiment of the present disclosure, an interface electron excitation spectrum may be obtained by performing Fourier transform on a target function to be measured.

[0091] According to the embodiments of the present disclosure, the time domain distribution of the electronic sum-frequency signal is determined according to the up-conversion pulse field distribution and the function to be measured, and then the time domain distribution of the electronic sum-frequency signal is Fourier transformed to obtain the frequency domain distribution of the electronic sum-frequency signal. According to the frequency domain distribution of the electronic sum-frequency signal and N electronic sum-frequency spectra, the frequency domain component can be obtained, and the frequency domain component is inversely Fourier transformed to obtain the time domain component. Based on the time domain component, the time domain distribution of the electronic sum-frequency signal, the up-conversion pulse field distribution and the preset parameters, the function to be measured is iterated to obtain the target function to be measured, thereby avoiding sacrificing the intensity of the up-conversion light, thereby improving the intensity of the electronic sum-frequency light signal, and achieving a higher signal-to-noise ratio of the interface electronic excitation spectrum while ensuring that the frequency resolution of the interface electronic excitation spectrum is high, and the electronic excitation spectrum carries phase information.

[0092] According to the embodiments of the present disclosure, a series of electron sum frequency spectra can be obtained by using ultrashort laser pulses as up-conversion light and by scanning the delay between the ultrashort laser pulse and another laser pulse that resonates with the sample. The series of electron sum frequency spectra are further analyzed and processed using a time-domain stacked scanning iterative algorithm, thereby improving the intensity of the electron sum frequency signal and ensuring that an interface electron excitation spectrum with a high signal-to-noise ratio and phase information is obtained under the premise of high frequency resolution, thereby being able to more accurately reveal the study of interface electronic structure and dynamics.

[0093] Figure 4 The optical path diagram of the interface electron excitation spectrum based on time domain and frequency stack scanning according to an embodiment of the present disclosure is schematically shown.

[0094] like Figure 4 As shown, the optical path diagram of the interface electron excitation spectrum based on time domain and frequency stack scanning includes a femtosecond pulse laser light source 411, a short infrared light parametric amplifier 412, a non-collinear light parametric amplifier 413, an electric translation stage 414, a K9 glass window 415, a parabolic mirror 416, a sample adjustment stage 417, a convex lens 418, a monochromator 419, a charge coupled device image sensor 420 and a computer control system 421.

[0095] According to an embodiment of the present disclosure, the femtosecond pulse laser light source 411 may be used to emit laser pulses, and may emit laser pulses to the short infrared optical parametric amplifier 412 and the non-collinear optical parametric amplifier 413 .

[0096] According to an embodiment of the present disclosure, the second laser pulse as up-converted light may be a short infrared laser pulse output by the short infrared light parametric amplifier 412, with a central wavelength of 1839 nm. The time domain field distribution of the second laser pulse as up-converted light has been characterized by a frequency-resolved optical gating experiment, and its pulse width is about 126 fs, which can be used as a known light field.

[0097] According to an embodiment of the present disclosure, the first laser pulse can be output by a set of commercial non-collinear optical parametric amplifiers 413, with a central wavelength of 880 nm. The autocorrelation experimental results show that the pulse width of the first laser pulse is about 26 fs.

[0098] According to an embodiment of the present disclosure, the time delay between the first laser pulse and the second laser pulse can be scanned using the electric translation stage 414. The movement of the electric translation stage 414 can be controlled by a computer control system. Moving the electric translation stage 414 can change the optical path of the second laser pulse, thereby changing the time delay between the first laser pulse and the second laser pulse. When the input electric translation stage 414 is the first laser pulse, the optical path of the first laser pulse can also be changed, thereby changing the time delay between the first laser pulse and the second laser pulse. For example, with a step size of 50 fs, the interface electron excitation spectra under 8 time delays are obtained.

[0099] According to an embodiment of the present disclosure, a K9 glass window 415 can be used to introduce chirp into a laser pulse. A parabolic mirror 416 can focus the first laser pulse and the second laser pulse that pass through the non-collinear optical parametric amplifier 413 and the K9 glass window 415 onto a sample on a sample adjustment stage 417, and the sample adjustment stage 417 can be moved so as to achieve the first laser pulse resonantly exciting the sample and the second laser pulse overlapping in the focusing area on the sample surface. The electron and frequency signal emitted from the sample will pass through a convex lens 418 and enter a monochromator 419.

[0100] According to an embodiment of the present disclosure, a charge-coupled device (CCD detector) 420 image sensor and a monochromator 419 may also be controlled by a computer control system 421 .

[0101] Figure 5 The intensity distribution diagram of the electronic sum frequency signal under different time delays according to an embodiment of the present disclosure is schematically shown.

[0102] like Figure 5 As shown in Figure 1, the intensity distribution diagram of the electronic sum frequency signal under 8 time delays, where the horizontal axis represents the wavelength of the electronic sum frequency signal in nm and the vertical axis represents the time delay in fs. Figure 5 , it is possible to generate interfacial electronic excitation spectra with high frequency resolution.

[0103] Based on the above-mentioned method for generating an interface electron excitation spectrum based on time domain and frequency stack scanning, the present disclosure also provides an interface electron excitation spectrum generating device based on time domain and frequency stack scanning. Figure 6 The device is described in detail.

[0104] Figure 6 The structural block diagram of the interface electron excitation spectrum generation device based on time domain and frequency stack scanning according to an embodiment of the present disclosure is schematically shown.

[0105] like Figure 6 As shown, the interface electron excitation spectrum generation device 600 based on time domain and frequency stack scanning in this embodiment includes an acquisition module 610 , a generation module 620 and an obtaining module 630 .

[0106] The acquisition module 610 is used to acquire a first laser pulse and a second laser pulse in response to the interface electron excitation spectrum generation request, wherein the first laser pulse is used for resonant excitation of the sample and the second laser pulse is used for non-resonant excitation of the sample. In one embodiment, the acquisition module 610 can be used to perform the operation S210 described above, which will not be described in detail here.

[0107] The generating module 620 is used to generate N electronic sum frequency spectra according to the first laser pulse and the second laser pulse. In one embodiment, the generating module 620 can be used to perform the operation S220 described above, which will not be described in detail here.

[0108] The obtaining module 630 is used to iteratively process the N electronic sum frequency spectra to obtain the interface electron excitation spectrum. In one embodiment, the obtaining module 630 can be used to perform the operation S230 described above, which will not be described in detail here.

[0109] According to an embodiment of the present disclosure, the generation module 620 includes: a first generation submodule and a second generation submodule.

[0110] The first generating submodule is configured to determine N time delays between the first laser pulse and the second laser pulse.

[0111] The second generating submodule is used to generate electronic sum frequency spectra of the N time delays according to the N time delays.

[0112] According to an embodiment of the present disclosure, the first generating submodule includes: a first generating unit.

[0113] The first generating unit is used for scanning the first laser pulse and the second laser pulse at a preset time interval to obtain N time delays, wherein the preset time interval is smaller than the pulse width of the second laser pulse.

[0114] According to an embodiment of the present disclosure, the second generation submodule includes: a second generation unit and a third generation unit.

[0115] The second generating unit is used to generate N electronic sum frequency signals according to the first laser pulse and the second laser pulse based on the N time delays.

[0116] The third generating unit is used to generate N time-delayed electron sum-frequency spectra according to the N electron sum-frequency signals.

[0117] According to an embodiment of the present disclosure, the obtaining module 630 includes: a first obtaining submodule, a second obtaining submodule, a third obtaining submodule, a fourth obtaining submodule and a fifth obtaining submodule.

[0118] The first obtaining submodule is used to determine the time domain distribution of the electronic sum frequency signal according to the up-conversion pulse field distribution and the function to be measured, wherein the up-conversion pulse field distribution is jointly determined by the second laser pulse.

[0119] The second obtaining submodule is used to perform Fourier transform on the time domain distribution of the electronic sum-frequency signal to obtain the frequency domain distribution of the electronic sum-frequency signal.

[0120] The third obtaining submodule is used to obtain the frequency domain component according to the frequency domain distribution of the electronic sum frequency signal and N electronic sum frequency spectra.

[0121] The fourth obtaining submodule is used to update the function to be measured based on the frequency domain component, the frequency domain distribution of the electronic and frequency signal, the up-conversion pulse field distribution and the preset parameters to obtain the target function to be measured.

[0122] The fifth submodule is used to perform Fourier transform on the target function to be measured to obtain the interface electron excitation spectrum.

[0123] According to an embodiment of the present disclosure, the fourth obtaining submodule includes: a first obtaining unit and a second obtaining unit.

[0124] The first obtaining unit is used to perform inverse Fourier transform on the frequency domain component to obtain the time domain component.

[0125] The second obtaining unit is used to obtain the target function to be measured according to the time domain component, the time domain distribution of the electronic sum frequency signal, the up-conversion pulse field distribution and the preset parameters.

[0126] According to an embodiment of the present disclosure, the third obtaining submodule includes: a third obtaining unit and a fourth obtaining unit.

[0127] The third obtaining unit is used to determine the phase of the electronic sum-frequency signal according to the frequency domain distribution of the electronic sum-frequency signal and N electronic sum-frequency spectra.

[0128] The fourth obtaining unit is used to obtain the frequency domain component according to the phase of the electronic sum frequency signal and the frequency domain distribution of the electronic sum frequency signal.

[0129] According to an embodiment of the present disclosure, any multiple modules of the acquisition module 610, the generation module 620 and the acquisition module 630 can be combined into one module for implementation, or any one of the modules can be split into multiple modules. Alternatively, at least part of the functions of one or more of these modules can be combined with at least part of the functions of other modules and implemented in one module. According to an embodiment of the present disclosure, at least one of the acquisition module 610, the generation module 620 and the acquisition module 630 can be at least partially implemented as a hardware circuit, such as a field programmable gate array (FPGA), a programmable logic array (PLA), a system on a chip, a system on a substrate, a system on a package, an application-specific integrated circuit (ASIC), or can be implemented by hardware or firmware such as any other reasonable way of integrating or packaging the circuit, or implemented in any one of the three implementation methods of software, hardware and firmware or in any appropriate combination of any of them. Alternatively, at least one of the acquisition module 610, the generation module 620 and the acquisition module 630 can be at least partially implemented as a computer program module, and when the computer program module is run, the corresponding function can be performed.

[0130] Figure 7 A block diagram of an electronic device suitable for implementing a method for generating an interface electron excitation spectrum based on time domain and frequency stack scanning according to an embodiment of the present disclosure is schematically shown.

[0131] like Figure 7 As shown, the electronic device 700 according to an embodiment of the present disclosure includes a processor 701, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 702 or a program loaded from a storage part 708 to a random access memory (RAM) 703. The processor 701 may include, for example, a general-purpose microprocessor (such as a CPU), an instruction set processor and / or a related chipset and / or a special-purpose microprocessor (for example, an application-specific integrated circuit (ASIC)), etc. The processor 701 may also include an onboard memory for caching purposes. The processor 701 may include a single processing unit or multiple processing units for performing different actions of the method flow according to an embodiment of the present disclosure.

[0132] In RAM 703, various programs and data required for the operation of electronic device 700 are stored. Processor 701, ROM 702 and RAM 703 are connected to each other via bus 704. Processor 701 performs various operations of the method flow according to the embodiment of the present disclosure by executing the program in ROM 702 and / or RAM 703. It should be noted that the program can also be stored in one or more memories other than ROM 702 and RAM 703. Processor 701 can also perform various operations of the method flow according to the embodiment of the present disclosure by executing the program stored in the one or more memories.

[0133] According to an embodiment of the present disclosure, the electronic device 700 may further include an input / output (I / O) interface 705, which is also connected to the bus 704. The electronic device 700 may further include one or more of the following components connected to the I / O interface 705: an input portion 706 including a keyboard, a mouse, etc.; an output portion 707 including a cathode ray tube (CRT), a liquid crystal display (LCD), etc., and a speaker, etc.; a storage portion 708 including a hard disk, etc.; and a communication portion 709 including a network interface card such as a LAN card, a modem, etc. The communication portion 709 performs communication processing via a network such as the Internet. A drive 710 is also connected to the I / O interface 705 as needed. A removable medium 711, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed on the drive 710 as needed, so that a computer program read therefrom is installed into the storage portion 708 as needed.

[0134] The present disclosure also provides a computer-readable storage medium, which may be included in the device / apparatus / system described in the above embodiments; or may exist independently without being assembled into the device / apparatus / system. The above computer-readable storage medium carries one or more programs, and when the above one or more programs are executed, the method according to the embodiment of the present disclosure is implemented.

[0135] According to an embodiment of the present disclosure, the computer-readable storage medium may be a non-volatile computer-readable storage medium, for example, it may include but is not limited to: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In the present disclosure, a computer-readable storage medium may be any tangible medium containing or storing a program, which may be used by or in combination with an instruction execution system, an apparatus or a device. For example, according to an embodiment of the present disclosure, the computer-readable storage medium may include the ROM 702 and / or RAM 703 described above and / or one or more memories other than ROM 702 and RAM 703.

[0136] The embodiment of the present disclosure also includes a computer program product, which includes a computer program, and the computer program contains program code for executing the method shown in the flowchart. When the computer program product is run in a computer system, the program code is used to enable the computer system to implement the interface electron excitation spectrum generation method based on time domain and frequency stack scanning provided by the embodiment of the present disclosure.

[0137] The above functions defined in the system / device of the embodiment of the present disclosure are performed when the computer program is executed by the processor 701. According to the embodiment of the present disclosure, the system, device, module, unit, etc. described above can be implemented by a computer program module.

[0138] In one embodiment, the computer program may rely on tangible storage media such as optical storage devices, magnetic storage devices, etc. In another embodiment, the computer program may also be transmitted and distributed in the form of signals on a network medium, and downloaded and installed through the communication part 709, and / or installed from the removable medium 711. The program code contained in the computer program may be transmitted using any appropriate network medium, including but not limited to: wireless, wired, etc., or any suitable combination of the above.

[0139] In such an embodiment, the computer program can be downloaded and installed from the network through the communication part 709, and / or installed from the removable medium 711. When the computer program is executed by the processor 701, the above functions defined in the system of the embodiment of the present disclosure are performed. According to the embodiment of the present disclosure, the system, device, means, module, unit, etc. described above can be implemented by a computer program module.

[0140] According to an embodiment of the present disclosure, the program code for executing the computer program provided by the embodiment of the present disclosure can be written in any combination of one or more programming languages. Specifically, these computing programs can be implemented using high-level process and / or object-oriented programming languages, and / or assembly / machine languages. Programming languages ​​include, but are not limited to, Java, C++, python, "C" language or similar programming languages. The program code can be executed entirely on the user computing device, partially on the user device, partially on the remote computing device, or entirely on the remote computing device or server. In the case of a remote computing device, the remote computing device can be connected to the user computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or can be connected to an external computing device (for example, using an Internet service provider to connect through the Internet).

[0141] The flow charts and block diagrams in the accompanying drawings illustrate the possible architecture, functions and operations of the systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each box in the flow chart or block diagram can represent a module, a program segment, or a part of a code, and the above-mentioned module, program segment, or a part of a code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram or flow chart, and the combination of the boxes in the block diagram or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0142] It will be appreciated by those skilled in the art that the features described in the various embodiments of the present disclosure may be combined and / or combined in a variety of ways, even if such combinations and / or combinations are not explicitly described in the present disclosure. In particular, without departing from the spirit and teachings of the present disclosure, the features described in the various embodiments of the present disclosure may be combined and / or combined in a variety of ways. All of these combinations and / or combinations fall within the scope of the present disclosure.

[0143] The embodiments of the present disclosure are described above. However, these embodiments are only for illustrative purposes and are not intended to limit the scope of the present disclosure. Although the embodiments are described above, this does not mean that the measures in the various embodiments cannot be used in combination to advantage. Without departing from the scope of the present disclosure, those skilled in the art may make a variety of substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A method for generating an interface electron excitation spectrum based on time domain and frequency stack scanning, characterized in that: include: In response to a request for generating an interface electron excitation spectrum, acquiring a first laser pulse and a second laser pulse, wherein the first laser pulse is used for resonant excitation of a sample, and the second laser pulse is used for non-resonant excitation of the sample; Generate N electronic sum frequency spectra according to the first laser pulse and the second laser pulse, wherein N is an integer greater than or equal to 1; The N electron sum frequency spectra are iteratively processed to obtain an interface electron excitation spectrum.

2. The method according to claim 1, characterized in that The step of generating N electronic sum frequency spectra according to the first laser pulse and the second laser pulse comprises: determining N time delays between the first laser pulse and the second laser pulse; Based on the N time delays, an electron sum frequency spectrum of each of the N time delays is generated.

3. The method according to claim 2, characterized in that The determining N time delays between the first laser pulse and the second laser pulse comprises: The first laser pulse and the second laser pulse are scanned at a preset time interval to obtain the N time delays, wherein the preset time interval is smaller than a pulse width of the second laser pulse.

4. The method according to claim 3, characterized in that: Generating the respective electronic sum frequency spectra of the N time delays according to the N time delays comprises: generating N electronic sum frequency signals based on the N time delays and from the first laser pulse and the second laser pulse; According to the N electron sum frequency signals, N electron sum frequency spectra with respective time delays are generated.

5. The method according to claim 4, characterized in that The iterative processing of the N electronic sum frequency spectra to obtain an interface electronic excitation spectrum includes: Determining the time domain distribution of the electronic sum frequency signal according to the up-conversion pulse field distribution and the function to be measured, wherein the up-conversion pulse field distribution is determined by the second laser pulse; Performing Fourier transform on the time domain distribution of the electronic sum-frequency signal to obtain the frequency domain distribution of the electronic sum-frequency signal; Obtaining frequency domain components according to the frequency domain distribution of the electronic sum frequency signal and the N electronic sum frequency spectra; Based on the frequency domain component, the frequency domain distribution of the electronic sum frequency signal, the up-conversion pulse field distribution and preset parameters, the function to be measured is updated to obtain a target function to be measured; Performing Fourier transform on the target function to be measured to obtain the interface electron excitation spectrum.

6. The method according to claim 5, characterized in that The updating of the function to be measured based on the frequency domain distribution of the electronic sum-frequency signal to obtain a target function to be measured includes: Performing an inverse Fourier transform on the frequency domain component to obtain a time domain component; The target function to be measured is obtained according to the time domain component, the time domain distribution of the electronic sum frequency signal, the up-conversion pulse field distribution and preset parameters.

7. The method according to claim 6, characterized in that The obtaining of frequency domain components according to the frequency domain distribution of the electronic sum frequency signal and the N electronic sum frequency spectra comprises: Determining the phase of the electronic sum-frequency signal according to the frequency domain distribution of the electronic sum-frequency signal; The frequency domain component is obtained according to the phase sum of the electronic sum frequency signal and the N electronic sum frequency spectra.

8. A device for generating interface electron excitation spectrum based on time domain and frequency stack scanning, characterized in that: include: An acquisition module, configured to acquire a first laser pulse and a second laser pulse in response to a request for generating an interface electron excitation spectrum, wherein the first laser pulse is used for resonant excitation of the sample, and the second laser pulse is used for non-resonant excitation of the sample; A generating module, used for generating N electronic sum frequency spectra according to the first laser pulse and the second laser pulse; The obtaining module is used to iteratively process the N electronic sum frequency spectra to obtain an interface electronic excitation spectrum.

9. An electronic device, comprising: one or more processors; a memory for storing one or more computer programs, It is characterized in that the one or more processors execute the one or more computer programs to implement the steps of the method according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program or instruction stored thereon, characterized in that: When the computer program or instruction is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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