Multi-modal fusion detection device and method based on optical pumping and photoacoustic imaging

Abstract

The invention provides a multi-mode fusion detection device and method based on optical pumping and photoacoustic imaging, and relates to the technical field of fusion detection. In the device, the irradiation path of the first laser is configured to point to a target area after passing through the atomic gas chamber, and the irradiation path of the second laser is configured to point to a first detection position of the detection module after passing through the atomic gas chamber, namely, the detection path of the atomic gas chamber can be used for realizing magnetic field detection and also can be used for detecting the target area after passing through the atomic gas chamber. Therefore, simultaneous acquisition of a magnetic field signal and a photoacoustic signal at a single detection point is realized. And the same-position (no equipment physical competition), self-time synchronization (no timestamp or multi-equipment information communication is needed), magnetic shielding is not needed, high time-space resolution and non-intrusive multi-modal fusion detection can be realized through hardware multiplexing, the equipment size can be reduced, series disturbance between multi-modal sensors is avoided as much as possible, and the detection precision is improved. The coupling research of the neural activity-blood flow condition is realized.

Description

Technical Field

[0001] The present invention relates to the field of fusion detection technology, and in particular to a multimodal fusion detection device and method based on optical pumping and photoacoustic imaging. Background Art

[0002] Currently, non-invasive brain-computer interfaces (BCIs) can be divided into two categories based on the type of biosignal detected: sensors that rely on electromagnetic physiological signals and sensors that rely on blood oxygenation (BPO). Examples of these sensors include electroencephalogram (EEG) and optically pumped magnetometers (OPM). Examples of BPO sensors include functional near-infrared spectroscopy (fNIRS) and photoacoustic imaging (PAI).

[0003] EEG and OPM sensors detect the electric and magnetic fields generated by physiological activity (including cardiac and cerebral magnetometry) to help analyze the immediate changes in the human body as it responds to different scenarios or demands. fNIRS and PAI sensors stimulate tissue with lasers and detect photoacoustic signals generated by changes in blood oxygen levels or photothermal effects, providing information on blood oxygen levels and tissue structure and function.

[0004] Sensors that rely on electromagnetic physiological signals have high temporal resolution but low spatial resolution, while sensors that rely on blood oxygenation have low temporal resolution but high spatial resolution. Therefore, currently common multimodal brain-computer interfaces generally use a multimodal fusion solution of electromagnetic physiological signals and blood oxygenation physiological signals to provide fast dynamic information as well as accurate blood oxygenation and spatial positioning information.

[0005] However, in the existing technologies, EEG sensors, fNIRS sensors, OPM sensors, and PAI sensors are all independent devices, which brings the following problems: 1. Location co-location issues. Whether it is the traditional EEG and fNIRS multimodal system or the emerging OPM and PAI multimodal multiplexing system, due to the essential differences in the physical structure and functional principles of these devices, it is difficult for them to share measurement points in the same setting: a) Example 1: In traditional multimodal systems, bulky fNIRS optical fibers, EEG cables, and electrodes compete for head space, and coupling EEG electrodes and fNIRS sources and detectors to the subject's head presents mechanical challenges (distance greater than 1 cm). b) Example 2 involves an emerging multimodal system where the EEG and OPM multimodal system requires a custom EEG sensor consisting of a Ag / AgCl powder sintered cylinder with silver-plated copper wire to ensure that the residual magnetic field induced is less than 50 pT and the distance is greater than 2 cm without causing changes in the power spectral density of the OPM; c) Example 3 involves emerging multimodal systems, where the EEG and PAI multimodal systems need to ensure that the frequency multiplexing of the high-channel light source system does not cause electrical crosstalk to the EEG within 1 cm.

[0006] 2. Time synchronization issues. In order to achieve synchronization of multimodal time axes when recording independent EEG sensors, fNIRS sensors, OPM sensors, and PAI sensors, the commonly used methods are to align timestamps or adopt a central synchronization control system or share certain hardware devices. Aligning timestamps ensures that the data collected from different devices can be accurately matched on the time axis, while the central synchronization control system uses a unified trigger mechanism to start all measurement devices at the same time to ensure the synchronization of data collection. The reuse of hardware devices can include ADC multiplexing, light source multiplexing, etc. However, these methods are limited by the RF line structure, etc., and are still not enough to meet the time synchronization requirements of full-channel, long-term measurements; While both OPM and fNIRS utilize light sources, fNIRS cannot share its light source with OPM because the fNIRS light source must be activated in a precise sequence to avoid signal interference between different light sources. Furthermore, this time-division multiplexing technique requires strict timing control over the activation and deactivation of each light source. fNIRS relies on detecting the scattering and absorption of light in brain tissue, which is highly sensitive to the timing of light source activation. If not managed properly, this can lead to data capture errors and affect the accuracy of experimental results.

[0007] In summary, traditional brain-computer interfaces have problems such as measurement time asynchrony, position asynchrony, large device size, and series disturbances with some new multimodal sensors during the data fusion of electromagnetic physiological signals and blood oxygen signals. Summary of the Invention

[0008] In view of this, the purpose of the present invention is to provide a multimodal fusion detection device and method based on optical pumping and photoacoustic imaging, which can achieve co-location (no physical competition between devices), self-time synchronization (no need for timestamps or multi-device information communication), no need for magnetic shielding, high temporal and spatial resolution, and non-invasive multimodal fusion detection through hardware multiplexing. At the same time, it can reduce the size of the device, minimize series disturbances between multimodal sensors, and realize the coupled study of neural activity and blood flow conditions.

[0009] In order to achieve the above objectives, the technical solutions adopted in the embodiments of the present invention are as follows: In a first aspect, the present invention provides a multimodal fusion detection device based on optical pumping and photoacoustic imaging, comprising a laser generating module, an atomic gas chamber and a detection module; wherein the laser generating module is used to generate a first laser; wherein the first laser is set to a pulsed laser, and the irradiation path of the first laser is configured to point to a target area after passing through the atomic gas chamber, and the first laser is used to act on the atoms in the atomic gas chamber to an excited state during the opening phase of the pulse cycle, and the detection path of the atomic gas chamber is configured to point to the target area; the laser generating module is also used to generate a second laser at least during the closing phase of the pulse cycle of the first laser; wherein The irradiation path of the second laser is configured to point to the first detection position of the detection module after passing through the atomic gas chamber, and the wavelength of the second laser is configured to be away from the atomic excitation wavelength of the atomic gas chamber; the detection module is used to collect the photoacoustic signal corresponding to the first laser acting on the measured part when the measured part of the object is associated with the target area; the detection module is also used to use the first detection position to collect the laser change corresponding to the second laser after passing through the atomic gas chamber; the detection module is also used to determine the physiological signal of the object under test based on the laser change and the photoacoustic signal.

[0010] It should be understood that the multimodal fusion detection device based on optical pumping and photoacoustic imaging provided in the embodiments of the present application has the following beneficial effects: The first laser's irradiation path is configured to pass through the atomic gas cell and then point toward the target area. When the measured part of the object is aligned with the target area, the detection module can perform photoacoustic (PA) detection based on the photoacoustic signal generated after the first laser's interaction with the measured part, effectively implementing a photoacoustic sensor. The first laser is also configured to excite atoms in the atomic gas cell during the on-phase of its pulse cycle. After the atoms are excited, a second laser is generated during the off-phase of the first laser's pulse cycle, passing through the atomic gas cell. The wavelength of this second laser is configured to be away from the atomic excitation wavelength in the atomic gas cell. This detection module, by detecting changes in the laser light corresponding to the second laser after passing through the atomic gas cell, can detect the magnetic field based on the detected signal changes, effectively implementing an optically pumped magnetometer (e.g., an OPM). Since the irradiation path of the first laser is configured to point to the target area after passing through the atomic gas chamber, and the irradiation path of the second laser is configured to point to the first detection position of the detection module after passing through the atomic gas chamber, that is to say, the detection path of the atomic gas chamber can be used for both magnetic field detection and photoacoustic detection, thereby realizing the simultaneous acquisition of magnetic field signals and photoacoustic signals at a single detection point, that is, hardware multiplexing can be achieved to achieve co-location (no physical competition between devices), self-time synchronization (no need for timestamps or multi-device information communication), no need for magnetic shielding, high time-space resolution, non-invasive multimodal fusion detection, and at the same time can reduce the size of the device, minimize series disturbances between multimodal sensors, and realize coupled research on neural activity-blood flow conditions.

[0011] In addition, by using a first laser to excite the atoms in the atomic gas chamber, and using a second laser with an atomic excitation wavelength far away from the atomic gas chamber during the time period when the first laser is stopped (that is, the wavelength of the second laser is configured to be far away from the wavelength of the first laser), a magnetometer based on optical pumping is realized. This can avoid pump light interference, improve the signal-to-noise ratio, and share the light source architecture of PAI and OPM, integrating photoacoustic imaging with magnetic field measurement, to realize a non-invasive, long-term wearable fusion detection device (for example, a brain-computer interface).

[0012] In a second aspect, the present invention provides a multimodal fusion detection device based on optical pumping and photoacoustic imaging, wherein the device is set in a magnetic shielding environment during operation, and the device includes a laser generating module, an atomic gas chamber and a detection module; wherein the laser generating module is used to generate a first laser; wherein the first laser is set to be a continuous-wave laser (Continuous-Wave, CW) or a quasi-continuous wave (quasi-CW, QCW) laser, and the irradiation path of the first laser is configured to point to a target area after passing through the atomic gas chamber, the first laser is used to act on the atoms in the atomic gas chamber to an excited state, and the detection path of the atomic gas chamber is configured to point to the target area; the laser generating module is used to generate a first laser; wherein the first laser is set to be a continuous-wave laser (Continuous-Wave, CW) or a quasi-continuous wave (quasi-CW, QCW) laser, and the irradiation path of the first laser is configured to point to the target area after passing through the atomic gas chamber, and the first laser is used to act on the atoms in the atomic gas chamber to an excited state, and the detection path of the atomic gas chamber is configured to point to the target area; The generation module is also used to generate a second laser; wherein the irradiation path of the second laser is configured to point to the first detection position of the detection module after passing through the atomic gas chamber, and the wavelength of the second laser is configured to be away from the atomic excitation wavelength of the atomic gas chamber; the detection module is used to collect the photoacoustic signal corresponding to the first laser after the measured part of the measured object is associated with the target area; the detection module is also used to use the first detection position to collect the laser change corresponding to the second laser after passing through the atomic gas chamber; the detection module is also used to determine the physiological signal of the measured object based on the laser change and the photoacoustic signal.

[0013] In a third aspect, the present invention provides a multimodal fusion detection method based on optical pumping and photoacoustic imaging, comprising the following steps: detecting a detected part of the object using the device as described in any embodiment of the first aspect or the second aspect above.

[0014] In a fourth aspect, the present invention provides a magnetometer, which is set in a non-magnetic shielding environment during operation; the magnetometer is used to perform the following steps during measurement: each sensor unit of the magnetometer measures the instantaneous magnetic field value of its position in real time, and sends the instantaneous magnetic field value to the controller of the magnetometer; the controller calculates three compensation currents corresponding to the X, Y, and Z axes; the controller controls the three-axis compensation coil of the magnetometer according to the three compensation currents to generate a compensation magnetic field; wherein the compensation magnetic field is opposite to the direction of the external magnetic field.

[0015] In order to make the above-mentioned objects, features and advantages of the present invention more clearly understood, embodiments of the present invention are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments of the present invention. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 A schematic structural diagram of a multimodal fusion detection device based on optical pumping and photoacoustic imaging provided by an embodiment of the present invention; Figure 2 A schematic diagram of the output pulse period of the first laser provided in an embodiment of the present invention; Figure 3 A schematic diagram of a photoacoustic pressure signal transmitted as a photoacoustic signal corresponding to the first laser beam acting on the measured part according to an embodiment of the present invention; Figure 4 Another schematic diagram of a photoacoustic pressure signal transmitted as a photoacoustic signal corresponding to the first laser beam acting on the measured part according to an embodiment of the present invention; Figure 5 Another schematic diagram of a photoacoustic pressure signal transmitted as a photoacoustic signal corresponding to the first laser beam acting on the measured part according to an embodiment of the present invention; Figure 6 A schematic diagram of another structure of a multimodal fusion detection device based on optical pumping and photoacoustic imaging provided by an embodiment of the present invention; Figure 7 A flowchart of a multimodal fusion detection method based on optical pumping and photoacoustic imaging provided in an embodiment of the present application; Figure 8 Another flowchart of the multimodal fusion detection method based on optical pumping and photoacoustic imaging provided in an embodiment of the present application.

[0018] Marking Description: 110 - laser generating module; 120 - atomic gas chamber; 131 - photoacoustic detection module; 132 - photoelectric detection module; 133 - data processing module; 11 - first laser output port; 12 - second laser output port; 21 - laser input port; 22 - laser output port; 23 - detection port; 32 - laser receiving port; 31 - detection point; 140 - preset area; 200-Multimodal fusion detection device; 210-First laser; 211-Filter; 212-Focusing lens; 213-Beam hole; 214-Focusing lens; 215-Second laser; 216-Filter; 217-Focusing lens; 218-Beam hole; 219-Focusing lens; 220-Refractive lens; 230-Atomic gas chamber; 240-Balanced photodetector; 241-Spectrum splitter; 242-Photodetection port; 243-Photodetection port; 250-Signal amplifier; 251-Ultrasonic transducer; 253-Spectrum splitter; 254-Reference photodetection port; 260-Data acquisition device; 270-Fiber optic coupler; 271-Optical amplifier; 272-Diffuser. DETAILED DESCRIPTION

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0020] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are intended to fall within the scope of protection of the present invention.

[0021] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0022] It should be noted that, in the absence of conflict, the features in the embodiments of the present invention may be combined with each other.

[0023] Embodiments of the present invention provide a multimodal fusion detection device and method based on optical pumping and photoacoustic imaging. The device and method relate to technical fields such as brain-computer interface, quantum mechanics, neuroscience, optics, acoustics, and fusion detection. They can be used to realize non-invasive wearable BCI (Brain-Computer Interface) sensors. They can achieve co-location (no physical competition between devices), self-time synchronization (no need for timestamps or multi-device information communication), no need for magnetic shielding, high temporal-spatial resolution, and non-invasive multimodal fusion detection through hardware multiplexing. At the same time, they can reduce the size of the device, minimize series disturbances between multimodal sensors, and realize coupled research on neural activity (including brain magnetism and heart magnetism) and blood flow conditions.

[0024] The technical solution provided by the present invention will be described below with reference to the accompanying drawings.

[0025] First, a multimodal fusion detection device based on optical pumping and photoacoustic imaging provided by an embodiment of the present invention is introduced. Figure 1 , Figure 1 A schematic diagram of the structure of a multimodal fusion detection device based on optical pumping and photoacoustic imaging provided by an embodiment of the present invention. The multimodal fusion detection device based on optical pumping and photoacoustic imaging includes: a laser generating module 110, an atomic gas chamber 120 and a detection module 130.

[0026] 1. Laser generating module 110; The laser generating module 110 can generate the first laser and the second laser. In an optional embodiment, the laser generating module 110 may include a laser and a laser path control module (for specific implementation, please refer to the relevant parts of the embodiments below).

[0027] Optionally, the laser in the laser generating module 110 can adopt a DFB laser (Distributed Feedback Laser) - distributed feedback laser solution, or an ECDL (External Cavity Diode Laser) - external cavity laser solution as a light source; it can also be used as a seed laser for power amplification, using a tapered amplifier (tapered optical amplifier) ​​for amplification, or using an SOA (Semiconductor Optical Amplifier) ​​for power amplification.

[0028] The laser may further include optical components such as filters and / or polarizers that can be used to control the laser propagation path. The laser path control module is used to control the laser propagation path to achieve control of the laser path. For example, the laser path control module may include a refractor, or the laser path control module may include a refractor and a collimating lens.

[0029] In some optional embodiments, the laser path control module may further include a filter or a polarizer to achieve control over the laser path.

[0030] 2, atomic gas chamber 120; Atomic gas cell 120 is based on the principle of optically pumped magnetometers and provides a magnetic field-sensitive quantum medium. For example, atomic gas cell 120 can be configured as a rubidium atom (87Rb) gas cell. Depending on the actual application and implementation requirements, atomic gas cell 120 may also include a heating module, a modulated magnetic field generation module, and other components, though these are not limited to this.

[0031] Optionally, the heating module of the atomic gas chamber 120 is specifically implemented as follows: the atomic gas chamber 120 is heated to 100°C by an electric heater driven by 131.5kHz AC current. The AC heater is turned on during the on phase of the pulse cycle (i.e., during the pumping period) and turned off during the off phase of the pulse cycle (i.e., during the measurement period) to reduce magnetic noise generated by the heater.

[0032] During the off phase of the pulse cycle, the laser changes corresponding to the second laser are detected using either zero-crossing detection or phase-locked detection. Specifically, after the pumping phase, the pump beam is turned off, and the free induction decay (FID) signal of the spin precession is measured using a linearly polarized probe beam using zero-crossing detection.

[0033] Optionally, the modulation magnetic field generating module is specifically implemented as follows: a polarization coil is provided in the modulation magnetic field generating module, and the polarization coil is configured to apply a modulation magnetic field to the atomic gas cell according to preset modulation parameters, for example, a rotating magnetic field with an amplitude of approximately 18 μT and a frequency of ωm = 2π × 480 Hz, and a guide magnetic field Bz in the longitudinal direction. The total amplitude of the applied magnetic field is maintained at approximately 50 μT.

[0034] It can be understood that the atomic gas chamber 120, the photoelectric detection module 132 and other possible modules (such as a heating module, a modulated magnetic field generating module, etc.) in this embodiment cooperate with each other to realize the function of an atomic magnetometer (such as an OPM sensor).

[0035] 3. Detection module 130; The detection module 130 may include a photoacoustic detection module 131 , a photoelectric detection module 132 and a data processing module 133 .

[0036] The photoacoustic detection module 131 is used to detect photoacoustic wave signals, and can cooperate with the data processing module 133 to realize blood oxygen signal detection based on photoacoustic imaging according to the laser generated by the laser generating module 110.

[0037] The photoelectric detection module 132 can convert optical signals into electrical signals for detecting laser variation parameters (e.g., laser intensity variations, laser frequency signals, etc.). Furthermore, the photoelectric detection module 132 can cooperate with the atomic gas chamber 120 and the data processing module 133 to implement electromagnetic physiological signal detection based on the laser light generated by the laser generation module 110 using an optically pumped magnetometer.

[0038] The data processing module 133 is used to process the input data according to a preset algorithm program to achieve the corresponding algorithm purpose and output the data calculated according to the algorithm.

[0039] exist Figure 1In the embodiment, the laser generating module 110 may include a first laser output port 11 and a second laser output port 12. The atomic gas chamber 120 may include a laser inlet 21, a laser outlet 22, and a detection port 23. The detection path of the atomic gas chamber 120 may include a path from the detection port 23 to the target area 140. The photoacoustic detection module 131 may include a detection point 31. The photoelectric detection module 132 may include a laser receiving port 32. The photoacoustic detection module 131 and the photoelectric detection module 132 may be electrically connected to the data processing module 133, respectively.

[0040] The laser receiving port 32 can serve as the first detection position of the detection module 130 (can also be replaced by an optical pumping detection position), and the detection point 31 can serve as the second detection position (can also be replaced by a photoacoustic detection position).

[0041] exist Figure 1 In the embodiment, the laser path control module can be used to configure the irradiation path of the first laser to be directed to the target area 140 after passing through the atomic gas cell 120. The laser path control module can also be used to configure the irradiation path of the second laser to be directed to the first detection position of the detection module 130 after passing through the atomic gas cell 120.

[0042] In the embodiment of the present application, the atomic gas chamber 120 can be configured to be associated with the target area 140, that is, the atomic gas chamber 120 is configured to detect the target area 140. For example, the detection path of the atomic gas chamber 120 is configured to point to the target area 120. Specifically, in Figure 1 In FIG. 1 , the detection port 23 is aligned with the target area 140 . In addition, the detection point 31 is associated with the target area 140 .

[0043] For the embodiment, the following contents need to be explained: 1. In the embodiments, alignment includes: linear alignment between objects A and B, or indirect alignment between objects A and B via an optical device. For example, alignment in this context can be explained as follows: a laser beam emitted from point A is linearly aligned with point B; or a laser beam emitted from point A is redirected by some optical device and then aligned with point B.

[0044] 2. For the examples, Figure 1 The alignment conditions are merely examples and do not limit the alignment conditions between modules, units or components. The alignment between one laser entrance and exit and another laser entrance and exit may be linear alignment or indirect alignment.

[0045] 3. In this embodiment, detection point 31 is associated with target area 140. This means that detection point 31 is located near, around, or within target area 140, without limitation. Detection point 31 is associated with target area 140 to enable photoacoustic detection module 131 to detect target area 140.

[0046] In the embodiment of the present application, the detection module 130 can be implemented using technologies such as magnetic field modulation and phase-locked detection. For details, please refer to the relevant technical content and will not be repeated here.

[0047] The target area 140 can be understood as the location of the measured part of the measured object. The measured part is associated with the target area 140, which means that the measured part of the measured object is set in the target area.

[0048] For the multimodal fusion detection device based on optical pumping and photoacoustic imaging provided in this application, the pulse characteristics of the laser light source not only affect the thermal deposition mode and signal morphology of PAI, but also directly determine whether OPM uses continuous pumping to excite alkali metal atoms to the SERF state for measurement, or uses pulsed pumping combined with FID theory to complete magnetic field detection. Accordingly, for the multimodal fusion detection device in this application, the first laser can be set to a pulsed laser, or it can be set to a continuous wave laser (Continuous-Wave, CW) or a quasi-continuous wave (quasi-CW, QCW) laser. According to different laser setting methods, the specific implementation methods of the multimodal fusion detection device include the following schemes 1 and 2: Solution 1: A multimodal fusion detection device in which the first laser is set as a pulsed laser (the device can operate in both magnetic shielding and non-magnetic shielding environments): The laser generating module 110 generates a first laser, which is configured as a pulsed laser.

[0049] The irradiation path of the first laser can be configured to pass through the atomic gas cell 120 and then point to the target area 140. The path of the first laser is arranged in order: first laser output port 11 → incident port of the atomic gas cell 120 → atomic gas cell 120 → detection port 23 → target area 140.

[0050] Among them, such as Figure 1 As shown, the first laser is used to excite atoms in the atomic gas chamber 120 during the on phase of the pulse cycle. The laser generating module 110 is also used to generate a second laser during at least the off phase of the first laser pulse cycle. The path of the second laser, in order of chronological order, includes: second laser output port 12 → laser input port 21 → atomic gas chamber 120 → laser output port 22 → laser receiving port 32 → photoelectric detection module 132.

[0051] The second laser beam is configured to irradiate the first detection position (laser receiving port 32) of the detection module 130 after passing through the atomic gas cell 120. Furthermore, the wavelength of the second laser beam is configured to be away from the atomic excitation wavelength of the atomic gas cell. In other words, the wavelength of the second laser beam is configured to be away from the wavelength of the first laser beam.

[0052] The detection module 130 is used to: when the measured part of the object is associated with the target area 130, collect the photoacoustic signal corresponding to the first laser acting on the measured part; use the first detection position to collect the laser change corresponding to the second laser after passing through the atomic gas chamber 120; and determine the physiological signal of the object based on the laser change and the photoacoustic signal.

[0053] Among them, the physiological signals of the object under test are determined according to the laser changes and the photoacoustic signal conditions, including: determining the electromagnetic physiological signals of the object under test according to the laser changes; and determining the blood oxygen signal of the object under test according to the photoacoustic signal conditions.

[0054] The laser change condition includes one or more of the following data: laser frequency, intensity, polarization signal, zero crossing point, phase signal, etc. corresponding to the second laser after passing through the atomic gas chamber.

[0055] The amplitude or frequency of the Larmor precession and the magnetic field modulation signal can be based on laser signal observation schemes including but not limited to phase-locked detection or zero-crossing tracking, peak-to-peak detection, etc.

[0056] In this application, the electromagnetic physiological signal (corresponding to the electrical activity of neurons) can be described as: "the electromagnetic physiological signal generated by the synchronized dendritic current in the neuronal cluster". The electromagnetic physiological signal can also be replaced by the electrophysiological signal or the magnetophysiological signal. Specifically, for the non-invasive capture of the neuronal electric / magnetic field, the neuronal collection should form a functional entity (neuronal cluster). This is because a sufficiently large population of neurons should gradually operate in a coordinated manner and be spatially organized, in which the dendrites of multiple neurons generate currents simultaneously. This synchronization can significantly amplify the electrical signals, generating local field potentials (LFPs) and local magnetic fields (LMFs), which are collectively referred to as cortical sources (CSs) of electromagnetic physiological signals, forming the theoretical basis for the measurement of electroencephalogram (EEG) and magnetoencephalogram (MEG) signals.

[0057] The blood oxygen signal can be described as "changes in regional blood flow (rCBF) or metabolic rate of oxygen (CMRO2)" and can be used to map how neurons or muscles are firing.

[0058] In the present application, the photoacoustic detection module 131, the photoelectric detection module 132 and the data processing module 133 can serve as the detection module 130. The detection module 130 can collect the laser changes corresponding to the second laser after passing through the atomic gas chamber 120, and the photoacoustic signal corresponding to the first laser after the first laser acts on the measured part, when the measured part of the object is associated with the target area 140. Then, the electromagnetic physiological signal of the object under test is determined based on the laser changes and the photoacoustic signal. Specifically, the detection module 130 can output the electromagnetic physiological signal (electrophysiological signal, which can be understood as: the magnetic field changes caused by local neural discharge in the brain (or other parts) of the object under test) according to the laser changes (including the laser frequency signal), and output the blood oxygen signal of the object under test according to the photoacoustic signal.

[0059] For photoacoustic imaging, according to photoacoustic theory, the laser-induced photoacoustic signal is mainly affected by two timing constants: stress relaxation time and thermal relaxation time When the laser pulse width satisfies: When the photoacoustic signal is approximately induced by a single "short pulse," it can be roughly considered as being induced by a single "short pulse." Otherwise, it will enter the heat accumulation (Grüneisen saturation term)-dominated region or the heat diffusion-dominated region, which will significantly change the structural characteristics of the PAI signal and its interaction with MEG. Accordingly, in the embodiments of the present application, the pulse width of the first laser can be selected from any of the following width ranges: the first range, the second range, and the third range. The first range is configured as follows: stress relaxation time < pulse width < first empirical value < thermal relaxation time; specifically, the first empirical value may be 10 ns or a value slightly larger / smaller than 10 ns, and the first range is configured as follows: stress relaxation time < pulse width < first empirical value ≪ (much smaller than) thermal relaxation time.

[0060] The second range is configured as: first empirical value < pulse width < second empirical value < thermal relaxation time; specifically, the second empirical value may be 100ns or a value slightly larger / smaller than 100ns, and the second range is configured as: first empirical value < pulse width < second empirical value ≪ (much smaller than) thermal relaxation time.

[0061] The third range is configured as: pulse width ≥ thermal relaxation time.

[0062] For the first range: When the pulse width of the first laser is selected within the first range, the multimodal fusion detection device is specifically implemented as follows (also referred to as a quasi-transient short pulse implementation): First, in the first range, the laser pulse width is usually less than 10ns. If Δt is used to represent the pulse width, then Δt<10ns≪thermal relaxation time , the first empirical value can be set to 10ns. Figure 3 , when the pulse width of the first laser is selected within the first range, the photoacoustic pressure signal transmitted by the photoacoustic signal corresponding to the first laser acting on the measured part presents a positive and negative pulse shape. The thermal deposition process can be regarded as instantaneous injection, and the PAI signal presents a typical positive and negative pulse shape with almost no thermal diffusion tailing. Under this condition: PAI imaging has good thermal localization and a single positive pulse response characteristic. At this time, the multimodal fusion detection equipment can use FID-OPM and conventional pulse PAI architecture, using laser pulses as a unified trigger source, simultaneously stimulating photoacoustic signals and synchronously starting MEG signal acquisition, to achieve natural coupling of dual modalities in space and time.

[0063] The first range can be determined as follows: when the photoacoustic pressure signal transmitted by the photoacoustic signal corresponding to the first laser acting on the measured part presents a positive and negative pulse form, the corresponding pulse width range is the first range.

[0064] When the pulse width of the first laser is selected within the first range, the blood oxygen signal of the subject can be determined according to the following first formula: ; in, represents the photoacoustic signal, represents the Greeneisen coefficient at ambient temperature, represents the conversion efficiency from heat to sound, represents the light absorption coefficient, Indicates light intensity (unit is (W / cm2)), Indicates the illumination time.

[0065] It should be noted that this width range (the first range) has minimal impact on the modulation of the FID-OPM, is the most efficient for PAI imaging, and has the most compact system integration.

[0066] For the second range: When the pulse width of the first laser is selected within the second range, the multimodal fusion detection device is specifically implemented as follows (also referred to as a heat accumulation (Grüneisen saturation term) dominant region implementation): When the pulse width of the first laser is selected within the second range, for the photoacoustic pressure signal transmitted by the photoacoustic signal corresponding to the first laser acting on the measured part, the amplitude of the negative photoacoustic pulse is greater than the amplitude of the positive photoacoustic pulse. Figure 4When the laser pulse width exceeds 10 ns, the negative photoacoustic pulse P2 may show a larger amplitude than the first signal P1. This may be due to the fact that more energy is deposited in the object, resulting in a higher Green-Eisen coefficient (increased thermal expansion coefficient) due to the increase in the object temperature. As the laser pulse width increases, the amplitude of the second negative photoacoustic pulse P2 will increase accordingly until thermal saturation occurs (because it is much smaller than ).

[0067] In other words, the second range can be determined as follows: when the amplitude of the negative photoacoustic pulse of the photoacoustic pressure signal transmitted by the photoacoustic signal corresponding to the first laser acting on the measured part is greater than the amplitude of the positive photoacoustic pulse, the corresponding pulse width range is the second range.

[0068] When the pulse width of the first laser is selected within the second range, the blood oxygen signal of the subject is determined according to the following second formula: ; in, represents the photoacoustic signal, represents the Greeneisen coefficient at ambient temperature, represents the conversion efficiency from heat to sound, represents the light absorption coefficient, Indicates the light intensity, Indicates the illumination time, b represents the proportionality coefficient relating the absorbed heat energy to the change in the Grüneisen parameter, Δt represents the pulse width of the laser, represents the thermal relaxation time.

[0069] In this case, there is no positive optimal laser pulse width. ) will dominate, and the second formula can be simplified to: ; in, ; In this case, the OPM uses FID theory for detection. The intensity of the negative pulse P2 in the PAI signal will be greater than the intensity of the positive pulse P1. In this case, it is recommended to use the positive and negative pulse differential or directly measure the negative pulse for photoacoustic image reconstruction to improve contrast and system stability.

[0070] For the second range, the typical value of FID generally falls within this range. The pulse length is recommended to be set to 40.25ns. The best pumping efficiency can be obtained at this excitation length under this pulse width. The detection frequency is around 1kHz, which is sufficient to meet the detection needs of brain nerves.

[0071] When the pulse width of the first laser is selected within the third range, the multimodal fusion detection device is specifically implemented as follows (implementation method in the heat diffusion dominant region): When the pulse width of the first laser is selected within the third range, the amplitude of the negative photoacoustic pulse of the photoacoustic pressure signal transmitted by the photoacoustic signal corresponding to the first laser acting on the measured part first increases and then decreases. Figure 5 , when the laser pulse width exceeds the thermal relaxation time, that is ; At this time, the amplitude of the negative pulse term in the PAI signal shows a trend of "first increasing and then decreasing", and there is a clear optimal laser pulse width. The third range can be determined as follows: when the amplitude of the negative photoacoustic pulse of the photoacoustic pressure signal transmitted as the photoacoustic signal corresponding to the first laser acting on the measured part first increases and then decreases, the corresponding pulse width range is the third range.

[0072] For the third range: When the pulse width of the first laser is selected within the third range, the blood oxygen signal of the subject can be determined according to the following third formula: ; in, represents the photoacoustic signal, represents the Greeneisen coefficient at ambient temperature, represents the conversion efficiency from heat to sound, represents the light absorption coefficient, Indicates the light intensity, Δt represents the laser pulse width, represents the thermal relaxation time. In this case, .

[0073] It is understood that the correct selection of laser pulse width is crucial to maximize the nonlinear PA signal. More importantly, the critical pulse width is a unique parameter that can characterize the thermal nonlinearity of different materials and can be further used for contrast enhancement imaging. If the values ​​are not consistent, it is necessary to scan the pulse width Δt and analyze whether the amplitude of P2 meets the expectation of the third formula.

[0074] Optionally, when the pulse width of the first laser is selected within the first range, the pulse width of the first laser is determined based on the first optical pumping reference pulse width. For example, the pulse width of the first laser is set to be equal to or approximately 10 ns (the first optical pumping reference pulse width).

[0075] When the pulse width of the first laser is selected within the second range, the pulse width of the first laser is determined according to the second optical pumping reference pulse width. For example, the pulse width of the first laser is set to be equal to or approximately 40.25 ns (the second optical pumping reference pulse width).

[0076] When the pulse width of the first laser is selected within the first range or the second range, the highest pumping efficiency can be achieved by setting the first optical pumping reference pulse width / the second optical pumping reference pulse width.

[0077] When the pulse width of the first laser is selected within the third range, the optimal pulse width of the first laser is determined based on the thermal relaxation time. For example, the optimal pulse width of the first laser is equal to or approximately equal to the thermal relaxation time. When the pulse width of the first laser is selected within the third range, the optimal photoacoustic effect can be achieved by setting the pulse width of the first laser to the same value as the thermal relaxation time.

[0078] It can be understood that the irradiation path of the first laser is configured to pass through the atomic gas cell 120 and then point to the target area 140. When the measured part of the object is associated with the target area 140, the detection module 130 can perform photoacoustic (PA) detection based on the photoacoustic signal corresponding to the first laser's interaction with the measured part, thereby realizing a photoacoustic sensor. The first laser is also configured to excite atoms in the atomic gas cell 120 during the on-phase of the pulse cycle. After the atoms are excited, a second laser is generated during the off-phase of the first laser's pulse cycle, passing through the atomic gas cell 120. The wavelength of the second laser is configured to be away from the atomic excitation wavelength of the atomic gas cell 120. In this way, by collecting the laser changes corresponding to the second laser after passing through the atomic gas cell 120, the detection module 130 can detect the magnetic field based on the detected signal changes, which is equivalent to realizing an optically pumped magnetometer (e.g., OPM). Since the irradiation path of the first laser is configured to point to the target area 140 after passing through the atomic gas chamber 120, and the irradiation path of the second laser is configured to point to the first detection position of the detection module 130 after passing through the atomic gas chamber 120, that is to say, the detection path of the atomic gas chamber 120 can be used for both magnetic field detection and photoacoustic detection, thereby realizing the simultaneous acquisition of magnetic field signals and photoacoustic signals at a single detection point, that is, hardware multiplexing can be achieved to achieve the same position (no physical competition between devices), self-time synchronization (no need for timestamps or multi-device information communication), no need for magnetic shielding, high time-space resolution, non-invasive multimodal fusion detection, and at the same time can reduce the size of the device, minimize series disturbances between multimodal sensors, and realize coupled research on neural activity-blood flow conditions.

[0079] In addition, in an embodiment of the present application, a magnetometer based on optical pumping is realized by using a first laser to excite the atoms in the atomic gas chamber, and using a second laser with an atomic excitation wavelength far away from the atomic gas chamber during the time period when the first laser is stopped, thereby avoiding pump light interference, improving the signal-to-noise ratio, and realizing a non-invasive, long-term wearable fusion detection device (such as a brain-computer interface).

[0080] In an optional embodiment, the atomic gas cell 120 includes a polarization coil. The polarization coil is configured to apply a modulated magnetic field to the atomic gas cell according to preset modulation parameters. Furthermore, the step of determining the electromagnetic physiological signal of the subject under test based on laser fluctuations may include determining the electromagnetic physiological signal or magnetic field modulation signal of the subject under test, including a vector dimension, based on the preset modulation parameters and the laser frequency signal. In this way, vector detection can be achieved through magnetic field modulation.

[0081] In an optional embodiment, the laser generating module is further configured to generate the second laser in a time period other than an off phase of a pulse cycle of the first laser.

[0082] In an optional embodiment, the output of the first laser is set to a square wave mode.

[0083] In an optional embodiment, the irradiation path of the first laser after passing through the atomic gas chamber 120 at least partially overlaps with the detection path of the atomic gas chamber. This can further improve the degree of multiplexing between hardware. For details, please refer to Figure 6 It is understood that in the present invention, at least one of the signal amplifier (AMP) and the data acquisition device (DAQ) can be multiplexed according to actual application requirements. The specific multiplexing implementation method can be set by technicians according to requirements and will not be described in detail here.

[0084] Among them, the balanced photodetector in this article can include some accessories of a two-way signal amplifier (AMP).

[0085] In an optional embodiment, the multimodal fusion detection device based on optical pumping and photoacoustic imaging provided by the present application (the device described in Scheme 1) is set in a non-magnetic shielding environment or a magnetic compensation coil during operation.

[0086] It should be noted that in the existing technology, all measurements using wearable SERF magnetometers are carried out in a magnetically shielded room, while the optical gradient magnetometer based on FID theory proposed in this application (that is, the above-mentioned device) can detect brain magnetic and cardiac magnetic signals in the earth's environmental magnetic field (exposed to natural magnetic noise sources).

[0087] In an optional embodiment, when the pulse width of the first laser is selected within the third range, the first laser is also configured to perform subcutaneous thermal therapy on the measured part, and the accumulated laser energy can be used to induce a temperature rise of tens of degrees in the tissue, thereby realizing thermal therapy induction, temperature feedback imaging, and biomagnetic field detection in parallel.

[0088] Regarding the device described in Solution 1 above, the following is a partial derivation of the energy attenuation mechanism of the laser after passing through the atomic gas chamber. Based on this derivation, it can be concluded that the first laser in Device 1 supports photoacoustics: 1.1, superimpose the state of "transparent after pumping is completed" right-handed After optical pumping, S points to +z (the same applies to left-hand rotation), and the following formula is given: (6) 1.2, superimposed "strong light saturation" state When using FID mode, the intensity is generally much greater than When the transition is almost occupied, the absorption cross section is Downward adjustment: (7) Among them, the saturation intensity is defined as: when the light intensity When the FID resonant excitation is on, the ground state and excited state each account for 50%. The excitation of the simple assumption that there is no loss of harmony, so the Simplified to: (8) is Planck's constant; is the speed of light; is the line width; λ is the wavelength (e.g. 795nm).

[0089] In summary, the differential formula of the pump section in FID mode is obtained, formula (7). However, the differential formula that can be used currently corresponds to the continuous light source, and the pulse form of the experimental design needs to be integrated. The specific process is shown below.

[0090] 2. Integrate in the time domain and area to obtain the attenuation formula of "pulse flux" (here the single duration is Take the square wave pulse as an example, and the same applies to multiple pulses and pulses of different shapes) 2.1, define some variables and assumptions Definition, Pulse Flux (or "Energy Density per Unit Area"): (9) Get in Saturation pulse flux under conditions: (10) Assume that the pulse duration Select the appropriate one (according to the selection principle of the first range to the third range mentioned above), and the intra-pulse pumping results are excellent. The component of the atomic spin polarization on the z-axis in the tail of the pulse square wave Pumping is close to 1 (pumping is completed and enters the state in 1.2) Assume that the concentration and temperature in the Rb gas chamber are not uniform during the pumping process. 2.2, Integrate the z axis and time t (11) in: : unpolarized optical thickness; : Pump suppression approaches 0 when it is completely transparent at 1.2, which is the case at the end of the square wave. Approaching ; : Pulse saturation term, when The energy absorption rate of the atomic gas chamber drops significantly. Approaching .

[0091] 2.3, Inadequate coping strategies 1. Increase input pulse energy ; 2. Reduce , can be achieved by shortening the gas chamber length l or lowering the temperature T, but both have their own disadvantages, such as shortening the gas chamber will reduce the signal-to-noise ratio, and lowering the temperature will reduce the sensitivity; 3. Coating the atomic cell for multiple reflections.

[0092] Solution 2: A multimodal fusion detection device in which the first laser is set to a continuous-wave (CW) or quasi-continuous-wave (QCW) laser (the device can operate in a magnetically shielded environment): The laser generating module 110 generates a first laser, which is set to be a continuous-wave laser (CW) or a quasi-continuous-wave (quasi-CW) laser.

[0093] The irradiation path of the first laser can be configured to pass through the atomic gas cell 120 and then point to the target area 140. The path of the first laser is arranged in order: first laser output port 11 → incident port of the atomic gas cell 120 → atomic gas cell 120 → detection port 23 → target area 140.

[0094] Continuous-wave (CW) lasers specifically refer to those that provide uninterrupted laser output during operation. Quasi-continuous-wave (QCW) lasers operate by emitting laser light in an intermittent pattern, unlike the uniform energy distribution of single-mode continuous-wave lasers. The more concentrated energy distribution of QCW lasers means they have a higher energy density, resulting in greater penetration.

[0095] The first laser is used to excite the atoms in the atomic gas cell 120 .

[0096] The laser generating module 110 is also used to generate a second laser. The path of the second laser is arranged in order: second laser outlet 12 → laser inlet 21 → atomic gas chamber 120 → laser outlet 22 → laser receiving port 32 → photoelectric detection module 132.

[0097] The second laser beam is configured to irradiate the first detection position (laser receiving port 32) of the detection module 130 after passing through the atomic gas cell 120. Furthermore, the wavelength of the second laser beam is configured to be away from the atomic excitation wavelength of the atomic gas cell. In other words, the wavelength of the second laser beam is configured to be away from the wavelength of the first laser beam.

[0098] The detection module 130 is used to: when the measured part of the object is associated with the target area 130, collect the photoacoustic signal corresponding to the first laser acting on the measured part; use the first detection position to collect the laser change corresponding to the second laser after passing through the atomic gas chamber 120; and determine the physiological signal of the object based on the laser change and the photoacoustic signal.

[0099] Among them, the physiological signals of the object under test are determined according to the laser changes and the photoacoustic signal conditions, including: determining the electromagnetic physiological signals of the object under test according to the laser changes; and determining the blood oxygen signal of the object under test according to the photoacoustic signal conditions.

[0100] The laser change condition includes: laser intensity and polarization change signal corresponding to the second laser after passing through the atomic gas chamber.

[0101] Specifically, the photoacoustic detection module 131, the photoelectric detection module 132 and the data processing module 133 can serve as the detection module 130. When the measured part of the measured object is associated with the target area 140, the detection module 130 can collect the laser changes corresponding to the second laser after passing through the atomic gas chamber 120, and the photoacoustic signal corresponding to the first laser after the first laser acts on the measured part. Then, the physiological signal of the measured object is determined based on the laser changes and the photoacoustic signal. Specifically, the detection module 130 can output the electromagnetic physiological signal of the measured object based on the laser changes (including laser intensity and polarization change signals) (the electromagnetic physiological signal here can be understood as: the magnetic field changes caused by local neural discharges in the brain (or other parts) of the measured object), and output the blood oxygen signal of the measured object based on the photoacoustic signal.

[0102] When the system uses a continuous-wave laser (CW) or quasi-continuous-wave (quasi-CW) light source, in addition to the heat accumulation and diffusion within a single laser pulse, when the laser pulse repetition frequency (N pulses per second, pulse interval = 1 / n) increases, long-term heat accumulation and substrate temperature rise may also become significant. Both p1 and p2 are affected by an additional quasi-continuous wave temperature rise and saturation term, which is a function of the pulse number n. The photoacoustic (PA) signal in quasi-continuous wave mode can be represented as a superposition of the linear and nonlinear photoacoustic signals p1,2 induced by the previous individual pulses, as well as the quasi-continuous wave temperature rise and saturation term.

[0103] Therefore, in this embodiment, determining the blood oxygen signal of the subject according to the photoacoustic signal may include: determining the blood oxygen signal of the subject according to the following fourth formula: ; in, represents the photoacoustic signal, represents the difference between the front and back edges of the photoacoustic signal, B express , represents the conversion efficiency from heat to sound, represents the light absorption coefficient, Indicates the light intensity, Indicates the illumination time, b represents the proportionality coefficient relating the absorbed heat energy to the change in the Grüneisen parameter, n represents the number of pulses per second of the first laser, is the pulse interval, It is necessary to explain that OPM is calculated using SERF theory.

[0104] In some possible embodiments, the first laser is further configured to perform subcutaneous thermal therapy on the measured part, and the accumulated laser energy can be used to induce tissue temperature to rise by tens of degrees, thereby achieving thermal therapy induction, temperature feedback imaging, and biomagnetic field detection in parallel.

[0105] For the device described in the above scheme 1 / scheme 2, in an optional embodiment, assuming that the first laser propagates along the Z axis, the attenuation of the first laser at position z on the Z axis is calculated by the following fifth formula: ; The integral of the fifth formula is the formula (6) above. I represents the light intensity of the first laser at position z on the Z axis, It represents the light intensity when the first laser enters the atomic gas cell.

[0106] n represents the density of atoms in the atomic gas cell, n It can be calculated by empirical formula, such as K atom , is the Kelvin temperature.

[0107] represents the average photon spin. For an alkali metal atom that has not been pumped, any circularly polarized pump light s Can be considered as 1.

[0108] represents the component of the atomic spin polarization along the z-axis. Represents the atomic resonance frequency Frequency response near.

[0109] Indicates saturation intensity, defined as: when the light intensity When FID is resonantly excited, the ground state and excited state each account for 50%. The excitation of is simply assumed to be without loss of harmony, so we can Simplified to: (8) is Planck's constant; is the speed of light, is the line width, and λ is the wavelength (e.g. 795 nm).

[0110] in, .

[0111] represents the classical electron radius ( ), represents the speed of light ( ).

[0112] Represents the resonance intensity. For alkali metal atoms, the D1 transition for ≈1 / 3, D2 transition for ≈2 / 3.

[0113] represents the broadening of the atomic gas cell. Because pressure-induced broadening is usually much larger than Doppler broadening and natural broadening, usually in the order of 1 to 100 GHz, the following formula is used to describe the absorption line of alkali metal atoms: .

[0114] represents the resonant frequency; Indicates the full width at half maximum (FWHM). Taking K atom as an example, in a system with He as buffer gas, the pressure broadening of K atom is , amg is the unit of atomic density, 1 amg is defined as the density of an ideal gas molecule at 1 atmosphere and 0 ◦ Density at C.

[0115] For the fifth formula above, the calculation can be simplified when using FID theory, directly integrating distance and time. When using SERF theory, the Lambert W function can be considered to represent the light intensity. In addition to the incomplete pumping caused by CW lasers, due to the long pulse duration and low power (relative to the large gas chamber length), the z-axis component of the atomic spin polarization changes with the z-axis distance corresponding to I after the laser enters (depending on I). In this case, the analytical solution of I for the z-axis equation must be written as a Bernoulli-type equation using the Lambert-W function. In addition, spin relaxation cannot be ignored, and a new differential equation is required. Including transverse relaxation will result in the lack of a closed-form analytical solution.

[0116] In some possible embodiments, the laser generating module 110 includes two lasers, which generate a first laser and a second laser respectively. Specifically, the laser generating module 110 may include a detection laser and an optical pumping laser. The optical pumping laser and the detection laser serve as the light source of the OPM, and the optical pumping laser serves as the light source of the PAI. For this embodiment, please refer to Figure 6 Description of the multimodal fusion detection device 200 shown.

[0117] Please refer to Figure 6 , Figure 6 This is another structural diagram of a multimodal fusion detection device based on optical pumping and photoacoustic imaging provided by an embodiment of the present invention. Detailed description is as follows: The multimodal fusion detection device 200 may include: a first laser 210, a filter 211, a focusing lens 212, a beam hole 213, a focusing lens 214, a second laser 215, a filter 216, a focusing lens 217, a beam hole 218, a focusing lens 219, a refractive lens 220, an atomic gas chamber 230, a balanced photodetector 240, a spectrometer 241, a photodetection port 242, a photodetection port 243, a signal amplifier (AMP) 250, an ultrasonic transducer 251, a spectrometer 253, a reference photodetection port 254, a data acquisition device (DAQ) 260, a fiber optic coupler 270, an optical amplifier 271, and a diffuser 272.

[0118] It is understandable that, according to actual detection requirements, the multimodal fusion detection device 200 may also include Figure 6 More or fewer components not shown in the figure can be flexibly arranged by those skilled in the art and are not limited thereto.

[0119] for Figure 6 The multimodal fusion detection device 200 shown in FIG. 2 is provided. For the positional relationship and connection relationship between each device and component, please refer to FIG. Figure 6 The following will describe the embodiment from the perspective of the laser propagation path: Regarding the first laser propagation path: The first laser 210 can generate a first laser beam. After passing through the optical filter 211, focusing lens 212, beam aperture 213, and focusing lens 214, the first laser beam is directed toward the refracting lens 220. The first laser beam is then refracted by the refracting lens 220 and directed toward the atomic gas chamber 230. The first laser beam then passes through the atomic gas chamber 230 and is directed toward the fiber coupler 270. After being received by the fiber coupler 270, the first laser beam is directed toward the optical amplifier 271 and diffuser 272. After being processed by the optical amplifier 271 and diffuser 272, the first laser beam is directed toward the target area. In the target area, the first laser beam can interact with the measured part of the object being measured, generating a corresponding photoacoustic signal. This photoacoustic signal can be collected by the ultrasonic transducer 251, and the collected signal can then be transmitted to the signal amplifier 250 and the data acquisition device 260.

[0120] Regarding the second laser propagation path: Second laser 215 can generate a second laser. After passing through filter 216, focusing lens 217, beam aperture 218, and focusing lens 219, the second laser is emitted to beam splitter 253. Beam splitter 253 then splits the second laser into two beams: laser A and laser B. Laser A is aimed at atomic gas cell 230 and, after passing through atomic gas cell 230, is emitted to beam splitter 241. Beam splitter 241 can split laser A into two beams, which are emitted to photodetection port 242 and photodetection port 243, respectively. Photodetection port 242 and photodetection port 243 are each connected to a balanced photodetector 240. According to the OPM principle, parameters such as the intensity, polarization, or frequency of laser light A after passing through atomic gas chamber 230 will change due to changes in the physiological signals of the measured part of the subject. Photodetection ports 242 and 243 can collect signals such as the laser intensity, polarization change, or frequency change corresponding to laser light A, and transmit these signals to balanced photodetector 240 and data acquisition device 260. Laser light B is aligned with reference photodetection port 254, which can transmit the collected laser light B to signal amplifier 250 and data acquisition device 260.

[0121] During the above process, data acquisition device 260 can collect signals such as laser intensity, polarization change, or frequency change corresponding to laser light A after passing through atomic gas chamber 230, as well as photoacoustic signals corresponding to the first laser's interaction with the measured area. Furthermore, data acquisition device 260 can output electromagnetic physiological signals of the measured subject based on the laser intensity, polarization change, or frequency change signals, thereby implementing an optically pumped magnetometer (OPM). Data acquisition device 260 can also output the measured subject's blood oxygen signal based on the photoacoustic signal, thereby implementing a photoacoustic sensor, based on the PAI principle.

[0122] In some optional embodiments, the first laser 210 is an optical pump laser, and the second laser 215 is a detection laser. The detection laser can be a continuous-wave (CW) laser or a quasi-continuous-wave laser source, or a short-pulse or long-pulse laser source.

[0123] The wavelength of the pulsed laser generated by the optical pumping laser can be set to be close to or consistent with 795 nm, and the wavelength of the laser generated by the detection laser can be set to be away from 795 nm.

[0124] for Figure 6 The multimodal fusion detection device 200, the first laser 210 and the second laser 215 can realize the above Figure 1The laser generating module 110 in the embodiment. The refractive lens 220 can realize the above-mentioned laser path control module. The photoelectric detection port 242, the photoelectric detection port 243 and the balanced photoelectric detector 240 can realize the above-mentioned Figure 1 The photoelectric detection module 132 in the embodiment. The ultrasonic transducer 251 and the signal amplifier 250 can realize the above Figure 1 The photoacoustic detection module 131 in the embodiment. Figure 1 and Figure 6 The embodiment may have more or fewer corresponding relationships which are not described in detail in this embodiment. The specific corresponding relationships can be set according to actual needs.

[0125] according to Figure 6 The embodiment shown and Figure 1 The corresponding relationship of the embodiments shown in FIG. 1 , in some optional embodiments, Figure 1 In the multimodal fusion detection device shown, the laser generating module 110 may include a first laser and a second laser. The first laser includes a first laser outlet 11, and the second laser includes a second laser outlet 12. The first laser is used to generate a first laser, and the second laser is used to generate a second laser.

[0126] According to the above Figure 1 、 Figure 6 In the embodiment shown, optionally, the first laser meets the photoacoustic pressure requirement of photoacoustic imaging and can excite the atoms in the atomic gas cell 120 , and the second laser meets the relaxation requirement of the optically pumped magnetometer principle when passing through the atomic gas cell 120 .

[0127] The first laser meets the photoacoustic pressure requirements for photoacoustic imaging, and the wavelength of the first laser is configured to be close to or consistent with the atomic excitation wavelength of the atomic gas chamber. For example, one or more of the intensity, frequency, and wavelength of the first laser meets the PAI design requirements. Specifically, when the first laser is aimed at the target area 140, it can induce an initial PAI sound pressure sufficient to be detected by the photoacoustic probe. The specific parameters can be set according to actual design requirements and PAI design principles, and are not limited or elaborated here.

[0128] When the second laser passes through atomic gas chamber 120, it meets the relaxation requirements of the optically pumped magnetometer principle. For example, one or more of the intensity, frequency, and wavelength of the second laser meets the relaxation parameter design requirements of the OPM. Specifically, a complete relaxation process can be completed within a single pulse, effectively providing energy to the OPM. The specific parameters can be set according to actual design requirements and OPM design principles, and are not limited or detailed here.

[0129] The present application also provides a magnetometer, which is arranged in a non-magnetic shielding environment during operation.

[0130] The magnetometer is used to perform the following steps 1.1 to 1.3 during measurement: In step 1.1, each sensor unit of the magnetometer measures the instantaneous magnetic field value at its location in real time and sends the instantaneous magnetic field value to the controller of the magnetometer.

[0131] In step 1.2, the controller calculates three compensation currents corresponding to the X, Y, and Z axes.

[0132] In step 1.3, the controller controls the three-axis compensation coils of the magnetometer according to the three compensation currents to generate a compensation magnetic field; wherein the compensation magnetic field is opposite to the direction of the external magnetic field.

[0133] Steps 1.1 to 1.3 represent the use of zero-order active compensation to quickly reduce common magnetic field interference (also known as coarse loop compensation).

[0134] Specifically, the magnetometer transmits the instantaneous magnetic field value of each sensor unit to a digital controller. The controller outputs three compensation currents with a bandwidth of 100-300Hz. These currents are applied via a DAC to three compensation coils coaxial with all sensor units, generating a constant compensation magnetic field in opposite directions. This ensures that the absolute value of the residual magnetic field at each unit is within 10 nT (empirical value).

[0135] During this process, the values ​​of the three compensation currents can be recorded synchronously to serve as the zero-order common field compensation amount B0(t) described below.

[0136] In an optional embodiment, the magnetometer is further used to perform the following steps 1.4 to 1.6 during measurement: In step 1.4, the controller periodically collects the residual magnetic field vectors of the collection channels corresponding to the respective sensor units.

[0137] In step 1.5, the controller determines the first-order spatial gradient of the compensation magnetic field according to the residual magnetic field vector and the three compensation currents.

[0138] In step 1.6, the controller controls the three-axis compensation coil according to the first-order spatial gradient to generate a gradient compensation field in the opposite direction to the first-order spatial gradient.

[0139] Steps 1.4 to 1.6 represent the process of periodically decomposing and suppressing spatial gradients to ensure high-precision measurements in a non-magnetically shielded environment (also known as thin-ring compensation).

[0140] Specifically, for example, with a period of 5 ms, the magnetometer collects the residual magnetic field vector b = [b1…b n ]ᵀ and its geometric coordinate matrix G, and use the least squares method to solve it in real time: ; Where b is an n×1 column vector representing the residual magnetic field components measured by the n channels in the magnetometer array (for example, the magnetic field projection value at each magnetometer location). These values ​​are collected at a certain time (for example, a 5 ms period). It represents a global bias magnetic field component or constant term that represents a portion of the uniform background magnetic field strength seen by all sensors (such as a uniform DC field or system bias). , , It represents the linear gradient component of the magnetic field in the three spatial directions, which can also be understood as the rate of change of the magnetic field with the x, y, and z spatial coordinates. The unit is T / m or nT / cm. Together, they describe a first-order magnetic field model: the value of the magnetic field at each location is determined by the constant term It is obtained by superimposing the linear changes of θ and θ at the position.

[0141] Among them, the obtained zero-order common field B0(t) can be directly deducted from all channel data; the obtained first-order spatial gradient ( ) is converted into a control quantity through a proportional coefficient and injected into the three-axis compensation coil of each independent channel in real time to generate a gradient compensation field opposite to the gradient direction to ensure high-precision measurement in a non-magnetic shielding environment.

[0142] In steps 1.1 through 1.6 above, the initial coarse loop compensation process rapidly reduces common magnetic field interference, followed by fine loop compensation, which periodically resolves and suppresses spatial gradients. This entire cycle operates at a high frequency (100-300 Hz for the coarse loop and 5 ms for the fine loop), ensuring high-precision measurements even in non-magnetically shielded environments.

[0143] In an alternative embodiment, two full-field magnetometers are used to directly measure the Larmor precession frequency of alkali metal vapor electron spins in a magnetic field. Compared to the voltage measurements associated with other magnetic field sensors, frequency measurements have a greater dynamic range and linearity. Furthermore, they do not require separate calibration; therefore, the first-order magnetic field gradient can be determined by simply subtracting the frequencies recorded from the two alkali metal vapor chambers. As can be appreciated, first-order gradiometers can be used to detect biomagnetic signals in more complex environments.

[0144] In an optional embodiment, the present application also provides an ultrasound probe that is implemented using air coupling, which can be used as a biosensor without coupling agent and electromagnetic shielding. In addition to traditional piezoelectric ceramics, the detection method also includes fiber optic ultrasonic transducer solutions. Please refer to Figure 7 , Figure 7 This is a flowchart of a multimodal fusion detection method based on optical pumping and photoacoustic imaging provided in an embodiment of the present application. This method can be applied to the above-mentioned device embodiment. The method includes the following steps: S710: The laser generating module generates a first laser.

[0145] S720: The laser generating module generates a second laser at least during the off phase of the pulse cycle of the first laser.

[0146] S730 , when the measured part of the measured object is associated with the target area, the detection module collects a photoacoustic signal corresponding to the first laser acting on the measured part.

[0147] S740: The detection module uses the first detection position to collect laser changes corresponding to the second laser after passing through the atomic gas chamber.

[0148] S750, the detection module determines the physiological signal of the object under test according to the laser change and the photoacoustic signal.

[0149] Understandably, about Figure 7 For the specific implementation and description of the method embodiment shown, please refer to the above Figure 1 、 Figure 6 The relevant contents of the illustrated embodiment will not be repeated here.

[0150] Please refer to Figure 8 , Figure 8 Another flowchart of a multimodal fusion detection method based on optical pumping and photoacoustic imaging provided in an embodiment of the present application, which can be applied to the above-mentioned device embodiment. The method includes the following steps: S810: The laser generating module generates a first laser.

[0151] S820: The laser generating module generates a second laser.

[0152] S830, when the measured part of the measured object is associated with the target area, the detection module collects the photoacoustic signal corresponding to the first laser acting on the measured part.

[0153] S840: The detection module uses the first detection position to collect laser changes corresponding to the second laser after passing through the atomic gas chamber.

[0154] S850, the detection module determines the physiological signal of the object under test according to the laser change and the photoacoustic signal.

[0155] Understandably, about Figure 8 For the specific implementation and description of the method embodiment shown, please refer to the above Figure 1 、 Figure 6 The relevant contents of the illustrated embodiment will not be repeated here.

[0156] The foregoing description is merely an embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A multimodal fusion detection device based on optical pumping and photoacoustic imaging, characterized in that: It includes a laser generating module, an atomic gas chamber and a detection module; wherein, The laser generating module is configured to generate a first laser; wherein the first laser is configured to be a pulsed laser, an irradiation path of the first laser is configured to pass through the atomic gas chamber and then point to a target area, the first laser is configured to act on atoms in the atomic gas chamber to an excited state during an open phase of a pulse cycle, and a detection path of the atomic gas chamber is configured to point to the target area; The laser generating module is further configured to generate a second laser at least during an off phase of a pulse cycle of the first laser; wherein an irradiation path of the second laser is configured to pass through the atomic gas chamber and point to the first detection position of the detection module, and a wavelength of the second laser is configured to be away from an atomic excitation wavelength of the atomic gas chamber; The detection module is configured to collect a photoacoustic signal corresponding to the first laser acting on the measured part when the measured part of the measured object is associated with the target area; The detection module is further configured to use the first detection position to collect laser changes corresponding to the second laser after passing through the atomic gas chamber; The detection module is further used to determine the physiological signal of the object under test based on the laser change and the photoacoustic signal.

2. The device according to claim 1, characterized in that Determining the physiological signal of the subject according to the laser change and the photoacoustic signal includes: Determining the electromagnetic physiological signal of the subject according to the laser change; wherein the laser change includes one or more of the following data: laser frequency, intensity, polarization signal, and zero-crossing point corresponding to the second laser after passing through the atomic gas chamber; The blood oxygen signal of the subject is determined according to the photoacoustic signal.

3. The device according to claim 2, characterized in that The pulse width of the first laser is selected from any one of the following width ranges: a first range, a second range, and a third range; The first range is configured as follows: stress relaxation time < pulse width < first empirical value < thermal relaxation time; The second range is configured as follows: first empirical value < pulse width < second empirical value < thermal relaxation time; The third range is configured as follows: pulse width ≥ thermal relaxation time.

4. The device according to claim 3, characterized in that When the pulse width of the first laser is selected within the first range, the photoacoustic pressure signal transmitted by the photoacoustic signal after the first laser acts on the measured part presents a positive and negative pulse shape; When the pulse width of the first laser is selected within the second range, for the photoacoustic pressure signal transmitted as the photoacoustic signal corresponding to the first laser acting on the measured part, the amplitude of the negative photoacoustic pulse is greater than the amplitude of the positive photoacoustic pulse; When the pulse width of the first laser is selected within the third range, for the photoacoustic pressure signal transmitted by the photoacoustic signal corresponding to the first laser acting on the measured part, the amplitude of the negative photoacoustic pulse shows a trend of first increasing and then decreasing.

5. The device according to claim 3, characterized in that When the pulse width of the first laser is selected within the first range, the step of determining the blood oxygen signal of the subject according to the photoacoustic signal comprises: The blood oxygen signal of the measured object is determined according to the following first formula: ； in, represents the photoacoustic signal, represents the Greeneisen coefficient at ambient temperature, represents the conversion efficiency from heat to sound, represents the light absorption coefficient, Indicates the light intensity, Indicates the illumination time.

6. The device according to claim 3, characterized in that When the pulse width of the first laser is selected within the second range, the step of determining the blood oxygen signal of the subject according to the photoacoustic signal comprises: The blood oxygen signal of the measured object is determined according to the following second formula: ； in, represents the photoacoustic signal, , represents the Greeneisen coefficient at ambient temperature, represents the conversion efficiency from heat to sound, represents the light absorption coefficient, Indicates the light intensity, Indicates the illumination time, b represents the proportionality coefficient relating the absorbed heat energy to the change in the Grüneisen parameter, Δt represents the pulse width of the laser, represents the thermal relaxation time.

7. The device according to claim 3, characterized in that When the pulse width of the first laser is selected within the third range, the step of determining the blood oxygen signal of the subject according to the photoacoustic signal comprises: The blood oxygen signal of the measured object is determined according to the following third formula: ； in, represents the photoacoustic signal, represents the Greeneisen coefficient at ambient temperature, represents the conversion efficiency from heat to sound, represents the light absorption coefficient, Indicates the light intensity, Δt represents the laser pulse width, represents the thermal relaxation time.

8. The device according to any one of claims 3 to 7, characterized in that When the pulse width of the first laser is selected within the first range, the pulse width of the first laser is determined according to the first optical pumping reference pulse width; When the pulse width of the first laser is selected within the second range, the pulse width of the first laser is determined according to the second optical pumping reference pulse width; When the pulse width of the first laser is selected from the third range, the optimal pulse width of the first laser is determined according to the thermal relaxation time.

9. The device according to claim 2, characterized in that The atomic gas cell includes a polarization coil; the polarization coil is configured to apply a modulation magnetic field to the atomic gas cell according to preset modulation parameters; Determining the electromagnetic physiological signal of the measured object according to the laser change includes: According to the preset modulation parameters and the laser frequency signal, the electromagnetic physiological signal or the magnetic field modulation signal including the vector dimension of the object under test is determined.

10. The device according to claim 9, characterized in that The AC heater of the atomic gas chamber is turned on during the on phase of the pulse cycle, and the AC heater of the atomic gas chamber is turned off during the off phase of the pulse cycle; wherein, during the off phase of the pulse cycle, the detection method of the laser change corresponding to the second laser includes: zero-crossing detection or phase-locked detection.

11. The device according to claim 1, characterized in that The irradiation path of the first laser after passing through the atomic gas cell at least partially overlaps with the detection path of the atomic gas cell.

12. The device according to claim 1, characterized in that The device is placed in a non-magnetic shielding environment or a magnetic compensation coil during operation.

13. The device according to claim 3, characterized in that When the pulse width of the first laser is selected within the third range, the first laser is further configured to perform subcutaneous thermal therapy on the measured site.

14. A multimodal fusion detection device based on optical pumping and photoacoustic imaging, characterized in that: The device is set in a magnetic shielding environment during operation, and the device includes a laser generating module, an atomic gas chamber and a detection module; wherein, The laser generating module is configured to generate a first laser; wherein the first laser is configured to be a continuous wave laser or a quasi-continuous wave laser, the irradiation path of the first laser is configured to pass through the atomic gas chamber and then point to a target area, the first laser is used to act on atoms in the atomic gas chamber to an excited state, and the detection path of the atomic gas chamber is configured to point to the target area; The laser generating module is further configured to generate a second laser; wherein the irradiation path of the second laser is configured to point to the first detection position of the detection module after passing through the atomic gas chamber, and the wavelength of the second laser is configured to be away from the atomic excitation wavelength of the atomic gas chamber; The detection module is configured to collect a photoacoustic signal corresponding to the first laser acting on the measured part when the measured part of the measured object is associated with the target area; The detection module is further configured to use the first detection position to collect laser changes corresponding to the second laser after passing through the atomic gas chamber; The detection module is further used to determine the physiological signal of the object under test based on the laser change and the photoacoustic signal.

15. The device according to claim 14, characterized in that Determining the physiological signal of the subject according to the laser change and the photoacoustic signal includes: Determining the electromagnetic physiological signal of the measured object according to the laser change; wherein the laser change includes: the laser intensity and polarization change signal corresponding to the second laser after passing through the atomic gas chamber; The blood oxygen signal of the subject is determined according to the photoacoustic signal.

16. The device according to claim 15, characterized in that Determining the blood oxygen signal of the subject according to the photoacoustic signal includes: The blood oxygen signal of the measured object is determined according to the following fourth formula: ； in, represents the photoacoustic signal, represents the difference between the front and back edges of the photoacoustic signal, B express , n represents the number of pulses per second of the first laser, is the pulse interval, represents the thermal relaxation time.

17. The device according to claim 14, characterized in that The first laser is further configured to perform subcutaneous thermal therapy on the measured part.

18. The device according to claim 1 or 14, characterized in that The first laser propagates along the Z axis, and the attenuation of the first laser at position z on the Z axis is calculated by the following formula: ； in, I represents the light intensity of the first laser at position z on the Z axis, represents the light intensity of the first laser when it enters the atomic gas cell, n represents the density of atoms in the atomic gas cell, represents the average photon spin, represents the component of the atomic spin polarization along the z-axis, Represents the atomic resonance frequency Frequency response near Indicates saturation intensity; in, , represents the classical electron radius, represents the speed of light, represents the resonance intensity, represents the widening of the atomic gas cell; , Indicates the actual frequency, represents the resonant frequency; Indicates full width at half maximum.

19. A multimodal fusion detection method based on optical pumping and photoacoustic imaging, characterized in that: The device according to any one of claims 1 to 18 is used to detect the detected part of the detected object.

20. A magnetometer, characterized in that The magnetometer is set in a non-magnetic shielding environment during operation; the magnetometer is used to perform the following steps during measurement: Each sensor unit of the magnetometer measures the instantaneous magnetic field value at its location in real time, and sends the instantaneous magnetic field value to the controller of the magnetometer; The controller calculates three compensation currents corresponding to the X, Y, and Z axes; The controller controls the three-axis compensation coils of the magnetometer according to the three compensation currents to generate a compensation magnetic field; wherein the compensation magnetic field is in a direction opposite to the external magnetic field.

21. The magnetometer according to claim 20, characterized in that The magnetometer is also used to perform the following steps during measurement: The controller periodically collects the residual magnetic field vector of the collection channel corresponding to each sensor unit; The controller determines the first-order spatial gradient of the compensation magnetic field according to the residual magnetic field vector and the three compensation currents; The controller controls the three-axis compensation coil according to the first-order spatial gradient to generate a gradient compensation field in a direction opposite to the first-order spatial gradient.

Images