A method and device for remote voice conversation interception based on Rydberg atoms

Abstract

The application discloses a remote voice conversation listening method based on Rydberg atoms, which comprises the following steps: a probe light, a decoration light and a coupling light are used to cooperatively excite rubidium atoms in a rubidium atom gas chamber to a high Rydberg state, the frequency of the coupling light is scanned, an EIT spectrum is obtained, and an EIT resonance point is acquired; the frequency and power of a local microwave are adjusted, the frequency of the coupling light is scanned, and the EIT spectrum exhibits a critical state of AT splitting; the local microwave K L is used to scan the frequency of the coupling light after being reflected by a to-be-detected target to the rubidium atom gas chamber, an EIT-AT spectrum and a superposition spectrum of a vibration signal K S are acquired; the frequency of the coupling light is locked at the EIT resonance point, and the vibration signal K S is restored; and the vibration signal K S is denoised. The application further discloses a remote voice conversation listening device based on Rydberg atoms, wherein, when the device is used for listening, a vibration signal in a human voice frequency range is detected, and vibrations outside the human voice frequency are shielded. The application has a simple structure and does not need complex demodulation and filtering and amplifying links.

Description

Technical Field

[0001] This invention belongs to the field of atomic and molecular optical physics research, specifically relating to a remote voice dialogue eavesdropping method based on Rydberg atoms, and also to a remote voice dialogue eavesdropping device based on Rydberg atoms. Background Technology

[0002] Current methods for remote voice communication signal interception primarily rely on laser-based techniques that transmit voice signals via reflection. This technology involves sending a laser beam to a destination, transmitting the signal through its reflection, and then reconstructing the audio information via complex demodulation, filtering, and amplification circuitry. It has wide applications in communication and eavesdropping. However, this technology requires high-quality laser beams, and lasers can only propagate in straight lines. Furthermore, the reception process necessitates complex demodulation, filtering, and amplification stages, increasing system complexity and cost. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings of current laser-based remote voice conversation signal eavesdropping technology by providing a Rydberg atom-based remote voice conversation eavesdropping method and a Rydberg atom-based remote voice conversation eavesdropping device, thus solving the problems of traditional technology being susceptible to interference and having complex and costly systems.

[0004] The objective of this invention is achieved through the following technical means:

[0005] A remote voice conversation eavesdropping device based on Rydberg atoms includes a rubidium atom gas chamber and a K-ray detector. P The light passes through a rubidium atom gas cell, is reflected by a polarizing beam splitter, and is transmitted to a photodetector, which is then connected to a computer; the embellished light K... D The embellished light K reflected by the beam splitter D The light passes through a polarizing beam splitter into a rubidium atom gas cell, where the adorned light K... D With probe light K P The coupled light K coincides and propagates in opposite directions; C The coupled light K is reflected by the mirror. C The light sequentially passes through the beam splitter and the polarizing beam splitter into the rubidium atom gas chamber. The coupled light K in the rubidium atom gas chamber... C With embellished light K D The local oscillator microwaves K emitted by the local oscillator microwave generator coincide and propagate in the same direction. L It passes through the rubidium atom gas chamber, reaches the detection target, and then returns to the rubidium atom gas chamber after being reflected.

[0006] A method for remote voice conversation monitoring based on Rydberg atoms, utilizing the aforementioned remote voice conversation monitoring device based on Rydberg atoms, includes the following steps:

[0007] Step 1, Detection light K P Adorned with light K D and coupled light K C The rubidium atoms in the rubidium atom gas cell were co-excited to a high Rydberg state, and the frequency of the coupled light was scanned to obtain the EIT spectrum and the EIT resonance point.

[0008] Step 2: Excite the microwave generator to emit local oscillator microwave K. L The local oscillator microwave K is adjusted by passing through the rubidium atom gas cell. L The frequency of the coupled light was scanned to the rubidium atom transition resonance point, and the local oscillator microwave K was adjusted. L The power-to-EIT spectrum exhibits the critical state of AT splitting;

[0009] Step 3, Local Oscillator Microwave K L After being reflected back into the rubidium atom gas cell by the target, the frequency of the coupled light is scanned to obtain the EIT-AT spectrum and vibrational signal K. S The superimposed spectrum;

[0010] Step 4: Lock the coupling light K C The frequency is at the EIT resonance point, and the vibration signal K is reconstructed. S ;

[0011] Step 5: Analyze the vibration signal K S Noise reduction.

[0012] The excitation of rubidium atoms in the rubidium atom gas chamber to a high Rydberg state is based on the following steps:

[0013] Detector light K P Passing through the rubidium atom gas cell, the light is reflected by a polarizing beam splitter to a photodetector, exciting the rubidium atoms to the first excited state; the adorned light K... D The embellished light K reflected by the beam splitter D The light passes through a polarizing beam splitter into the rubidium atom gas cell, exciting the rubidium atoms from the first excited state to an intermediate state; the coupled light K... C Reflected by the mirror, the particles pass through the beam splitter and polarizing beam splitter in sequence into the rubidium atom gas chamber, exciting the rubidium atoms from the intermediate state to the Gorridberg state.

[0014] The acquisition of EIT-AT spectrum and vibration signal K S The superimposed spectrum is based on the following steps:

[0015] Local oscillator microwave K L After passing through the rubidium atom gas chamber, it hits the vibrating detection target and is affected by the vibration signal K. S Modulation, to obtain the modulated signal K L +K S Modulation signal K L +K SAfter reflection, it returns to the rubidium atom gas cell and interacts with the local oscillator microwave K. L The combined action of these atoms induces a difference frequency effect, resulting in the vibrational signal K. S Scan the coupled light frequency to obtain the EIT-AT spectrum and the vibrational signal K sensed by the Rydberg atoms. S The superimposed spectrum.

[0016] The vibration signal K S Noise reduction includes the following steps:

[0017] Improve the detection light K P Adorned with light K D and coupled light K C Signal-to-noise ratio;

[0018] Use a bandpass filter to preserve the vocal frequency band;

[0019] Use Fourier transform or wavelet transform to separate human voice signals.

[0020] The vibration signal K S Noise reduction also includes the following steps:

[0021] Separation is achieved by utilizing blind source separation or independent component analysis, taking advantage of the statistical differences between noise and speech signals.

[0022] The detection light K P The wavelength is 780nm.

[0023] The coupled light K C The wavelength is 1260nm.

[0024] The decorative light K D The wavelength is 776nm.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] 1. This invention not only adjusts the frequency of the local oscillator microwave to the atomic transition resonance point, but also adjusts its intensity to the critical point of AT splitting, at which point the system is most sensitive to weak reflected signals;

[0027] 2. Couple the light K c The frequency is locked at the EIT resonance point, enabling the photodetector to directly read the vibration signal K from the modulation signal reflected back to the rubidium atom gas cell. S ;

[0028] 3. The present invention has a simple structure and does not require complex demodulation and filtering amplification stages. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of the remote voice conversation monitoring device based on Rydberg atoms according to the present invention.

[0030] Figure 2 This is a flowchart of the remote voice dialogue eavesdropping method based on Rydberg atoms according to the present invention;

[0031] Figure 3 To shut down the local oscillator microwave field, when scanning the frequency of the coupled light, the photodetector receives a typical EIT spectrum, with the horizontal axis representing the frequency detuning of the coupled light and the vertical axis representing the transmission intensity of the probe light.

[0032] Figure 4 To scan the frequency of the coupled light under the action of a local oscillator microwave field of a certain intensity, the EIT-AT spectrum received by the photodetector is shown. The horizontal axis represents the frequency detuning of the coupled light, and the vertical axis represents the transmission intensity of the probe light.

[0033] Figure 5 To scan the frequency of the coupled light under the action of the local oscillator microwave field, the EIT-AT spectrum is obtained when the AT split just appears; the horizontal axis represents the frequency detuning of the coupled light, and the vertical axis represents the transmission intensity of the probe light;

[0034] Figure 6 The EIT-AT spectrum received by the electrical detector and the vibrational signal K sensed by the Rydberg atoms. S The superimposed spectrum; the horizontal axis represents the frequency detuning of the coupled light, and the vertical axis represents the transmission intensity of the probe light;

[0035] Figure 7 After locking the frequency of the coupled light at the EIT resonant point, the electrical detector receives the detected vibration signal, with the horizontal axis representing time and the vertical axis representing the signal amplitude.

[0036] Among them, 1-local oscillator microwave generator, 2-rubidium atom gas cell, 3-detection target, 4-polarizing beam splitter, 5-photodetector, 6-computer, 7-beam splitter, 8-reflector. Detailed Implementation

[0037] To facilitate understanding and implementation of the present invention by those skilled in the art, the present invention will be further described in detail below with reference to embodiments. It should be understood that the embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0038] Example 1:

[0039] like Figure 1 As shown, a remote voice conversation monitoring device based on Rydberg atoms includes: a local oscillator microwave generator 1, a rubidium atom gas cell 2, a polarizing beam splitter 4, a photodetector 5, a computer 6, a beam splitter 7, and a reflector 8.

[0040] Detector light K PThe light passes through the rubidium atom gas chamber 2, is reflected by the polarizing beam splitter prism 4, and is transmitted to the photodetector 5, which is connected to the computer 6; the embellished light K D The embellished light K is reflected by beam splitter 7. D The light K passes through the polarizing beam splitter 4 and enters the rubidium atom gas chamber 2. The rubidium atom gas chamber 2 contains the adorned light K. D With probe light K P The coupled light K coincides and propagates in opposite directions; C The coupled light K reflected by mirror 8 C The light sequentially passes through beam splitter 7 and polarizing beam splitter 4 into rubidium atom gas chamber 2. The coupled light K in rubidium atom gas chamber 2... C With embellished light K D The local oscillator microwaves K emitted by local oscillator microwave generator 1 coincide and propagate in the same direction; L It passes through the rubidium atom gas chamber 2, reaches the detection target 3, and then returns to the rubidium atom gas chamber 2 after reflection. In this embodiment, the target to be measured is a glass window.

[0041] Example 2:

[0042] like Figure 2 As shown, a remote voice conversation monitoring method based on Rydberg atoms, utilizing the remote voice conversation monitoring device based on Rydberg atoms described in Example 1, includes the following steps:

[0043] Step 1, Detection light K P Adorned with light K D and coupled light K C The rubidium atoms in rubidium atom gas cell 2 were co-excited to a high Rydberg state, and the coupled light K was scanned. C The frequency was determined to obtain the EIT spectrum and the EIT resonance point.

[0044] Detector light K P The light passes through the rubidium atom gas chamber 2, is reflected by the polarizing beam splitter prism 4, and is then sent to the photodetector 5, exciting the rubidium atoms to the first excited state; the adorned light K... D The embellished light K is reflected by beam splitter 7. D The light passes through the polarizing beam splitter 4 and enters the rubidium atom gas chamber 2, exciting the rubidium atoms from the first excited state to the intermediate state; the coupled light K... C Reflected by mirror 8, the light sequentially passes through beam splitter 7 and polarizing beam splitter prism 4 into rubidium atom gas chamber 2, exciting the rubidium atoms from the intermediate state to the high Rydberg state. In this embodiment, the probe light K... P The wavelength is 780nm, and the embellished light K D The wavelength is 776nm, and the coupled light K C The wavelength is 1260nm.

[0045] When the probe light KP Adorned with light K D and coupled light K C Co-excitation of rubidium atoms in rubidium atom gas cell 2 to high Rydberg states to detect light K P After being transmitted to photodetector 5, the spectrum presented on computer 6 by scanning the coupling light frequency is EIT (electromagnetic induction transparency) spectrum. Figure 3 The EIT spectrum without a local oscillator microwave is shown. The horizontal axis represents the frequency detuning of the coupling light, and the vertical axis represents the transmission intensity of the probe light. When the frequency detuning of the coupling light Δ... c When =0, the corresponding point is the EIT resonance point.

[0046] Step 2: Excite microwave generator 1 to emit local oscillator microwave K L The local oscillator microwave K is adjusted by passing through the rubidium atom gas chamber 2. L The frequency of the coupled light was scanned to the rubidium atom transition resonance point, and the local oscillator microwave K was adjusted. L The power-to-EIT spectrum shows the critical state of AT splitting.

[0047] Local oscillator microwave generator 1 emits local oscillator microwave K L Passing through rubidium atom gas cell 2, when the local oscillator microwave K is adjusted... L When the frequency of the local oscillator K resonates with the energy level transition frequency of rubidium atoms in the high Rydberg state, the local oscillator microwave K... L The frequency is tuned to the rubidium atom transition resonance point, which is located in the GHz band. At this frequency, the atomic energy level splitting phenomenon, i.e., Autler-Townes splitting, is most significant. Within a specific field strength range, the local oscillator microwave K... L This can cause the EIT signal to produce an AT (Autler-Townes) splitting effect, resulting in two peaks. The spectrum displayed on the computer is the EIT-AT spectrum, such as... Figure 4 As shown (this is the critical state of non-AT splitting).

[0048] By adjusting the local oscillator microwave K L Power can cause the peaks of the EIT spectrum to split, and the splitting spacing will change with the local oscillator microwave K. L The intensity increases accordingly, and the relationship between the splitting distance Δf and the microwave electric field intensity E is expressed as: Δf = μE, where μ is the electric dipole moment of the rubidium atom in the high Rydberg state, and its magnitude is proportional to the square of the principal quantum number n. The two have a linear relationship. When the local oscillator microwave K L When the microwave power is adjusted to the critical state where the EIT spectrum just shows AT splitting, the spectrum displayed on computer 6 is as follows: Figure 5 The analytic spectrum is shown in the diagram, at which point the AT spectrum reaches its highest sensitivity to the detection signal.

[0049] Step 3, Local Oscillator Microwave K L After being reflected back to rubidium atom gas cell 2 by the target, the frequency of the coupled light is scanned to obtain the EIT-AT spectrum and vibrational signal K. S The superimposed spectrum.

[0050] Local oscillator microwave K L After passing through the rubidium atom gas chamber 2, it hit the detection target 3, where a tiny vibration signal K was detected within the frequency range of the target's acoustic communication. S (Including the vibrations generated by the target's acoustic waves and the noise within that frequency range, typically from tens of Hz to hundreds of kHz), and then the local oscillator microwave K incident on the target 3. L Vibration signal K S Modulation, to obtain the modulated signal K L +K S Modulation signal K L +K S After reflection, it returns to rubidium atom gas cell 2, where it interacts with the local oscillator microwave K. L The combined action of these atoms (rubidium atoms in the Rydberg state) induces a difference frequency effect, resulting in the vibrational signal K. S Scan the coupled light frequency to obtain the EIT-AT spectrum and the vibrational signal K sensed by the Rydberg atoms. S Superimposed spectra, such as Figure 6 As shown.

[0051] Step 4: Lock the coupling light K C The frequency is at the EIT resonance point, and the vibration signal K is reconstructed. S .

[0052] Locking the coupled light K using the PDH (Pound-Drever Hall) frequency stabilization method C The frequency is at the EIT resonance point, causing the EIT-AT spectrum to resonate with the vibrational signal K sensed by the Rydberg atom. S The superimposed spectrum is locked at the EIT resonance point Δ c =0, where Δ c The frequency detuning of the coupled light is due to the coupling light K... C The difference between the frequency of the coupled light and the atomic transition frequency, i.e., the K-frequency of the atomic transition, is the value of the frequency of the coupled light. C The amount of deviation from the resonant frequency. Due to the coupling light K C The frequency is locked, and photodetector 5 cannot detect the spectral signal; only the vibration signal K modulated onto the spectrum is detected. S When detected, the signal detected by photodetector 5 is the vibration signal K. S That is, distant speech signals (including target dialogue and noise).

[0053] The computer 6 displays the spectral signal and vibration signal K detected by the photoelectric probe 5. S The superimposed signal, the detected signal can also be understood as the vibration signal K S The modulated spectral signal, when coupled with light K C When the frequency is locked, meaning that frequency scanning of the spectrum is not performed, photodetector 5 will not detect the spectral signal, only the vibration signal K. S When detected, the signal detected by photodetector 5 is the vibration signal K. S ,like Figure 7 As shown, this utilizes the self-demodulation characteristic of Rydberg atomic detectors. In this process, rubidium atoms can directly reconstruct sound information without relying on electronic demodulation technology, achieving "self-demodulation." The entire process does not require complex amplification, filtering, and demodulation circuitry.

[0054] Step 5: Analyze the vibration signal K S Noise reduction.

[0055] In the process of using the Rydberg atom to detect sound signals, when the local oscillator microwave K... L When a person's voice shines through a glass window, it modulates microwaves and generates vibration information through the glass window. However, other vibrations (such as background noise) will also be modulated and introduce noise if they fall within the range of the person's voice.

[0056] The following steps can be taken to eliminate these noises:

[0057] Step 5.1: Optimize laser parameters and atomic system; for example, enhance the coupling field strength to amplify the signal sidebands and improve the probe beam K. P Adorned with light K D and coupled light K C Signal-to-noise ratio;

[0058] Step 5.2: Use a bandpass filter to preserve the vocal frequency band;

[0059] Step 5.3: Digital signal processing; such as Fourier transform or wavelet transform to separate the human voice signal.

[0060] For noise in the human voice frequency range, these methods cannot completely eliminate it because the noise shares the same frequency band as the signal. This is a fundamental limitation of all vibration sensing systems (not just the Rydberg system); other detection schemes (such as conventional laser interferometers or piezoelectric sensors) also face this problem.

[0061] Although co-frequency noise is unavoidable, the design of a Rydberg system can minimize its impact in the following ways:

[0062] 1. Spatial isolation: The local oscillator microwave field passing through the rubidium atom gas chamber 2 is focused onto the glass window to reduce the influence of non-target vibration areas;

[0063] 2. Advanced signal processing: Using blind source separation (BBS) or independent component analysis (ICA) in the digital domain, noise is partially separated by utilizing the statistical differences (such as non-Gaussianity) between noise and speech signals;

[0064] 3. Multi-sensor fusion: Combines inertial sensors to detect environmental vibrations and subtracts them in post-processing (requires additional hardware).

[0065] The core advantage of using Rydberg atomic detectors lies in their natural avoidance of noise in non-target frequency bands, thus simplifying noise management. This is reflected in the following:

[0066] 1. Noise selective modulation: Only the frequency components of glass vibration (human voice range) can modulate microwaves, while other noise (such as electromagnetic interference, optical jitter or ultra-low frequency vibration) will not be modulated, so no additional filtering is required;

[0067] 2. Quantum-enhanced anti-interference: Rydberg atoms are insensitive to non-resonant fields, reducing the impact of environmental electromagnetic noise (traditional sensors are susceptible to this type of noise interference).

[0068] 3. High signal-to-noise ratio fundamentals: The system's quantum-limited sensitivity (~nVcm) -1 Hz -2 This allows weak signals to be extracted from a low-noise substrate, indirectly mitigating the effects of co-frequency noise.

[0069] When using Rydberg atomic detectors, their inherent characteristics shield most irrelevant noise, making noise within the range of human voice the only major challenge, representing a significant improvement over traditional detection systems.

[0070] The specific examples described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific examples or use similar methods to replace them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A remote voice conversation monitoring device based on Rydberg atoms, comprising a rubidium atom gas chamber (2), characterized in that, Detector light K P The light passes through the rubidium atom gas chamber (2), is reflected by the polarizing beam splitter (4), and is transmitted to the photodetector (5). The photodetector (5) is connected to the computer (6). D The embellished light K reflected by the beam splitter (7) D The rubidium atom gas enters the rubidium atom gas chamber (2) through the polarizing beam splitter (4), and the rubidium atom gas chamber (2) contains the adorned light K D With probe light K P The coupled light K coincides and propagates in opposite directions; C The coupled light K reflected by mirror (8) C The light K passes sequentially through the beam splitter (7) and the polarizing beam splitter (4) into the rubidium atom gas chamber (2), where the coupled light K... C With embellished light K D The local oscillator microwaves K emitted by the local oscillator microwave generator (1) coincide and propagate in the same direction; L It passes through the rubidium atom gas chamber (2), reaches the detection target (3), and then returns to the rubidium atom gas chamber (2) after reflection. Detector light K P Adorned with light K D and coupled light K C The rubidium atoms in the rubidium atom gas cell (2) are co-excited to a high Rydberg state, and the frequency of the coupled light is scanned to obtain the EIT spectrum and the EIT resonance point; Excite the microwave generator (1) to emit local oscillator microwave K L The local oscillator microwave K is adjusted by passing through the rubidium atom gas cell (2). L The frequency of the coupled light was scanned to the rubidium atom transition resonance point, and the local oscillator microwave K was adjusted. L The power-to-EIT spectrum exhibits the critical state of AT splitting; Local oscillator microwave K L After being reflected back to the rubidium atom gas cell (2) by the target, the frequency of the coupled light is scanned to obtain the EIT-AT spectrum and vibrational signal K. S The superimposed spectrum; Lock-coupled light K C The frequency is at the EIT resonance point, and the vibration signal K is reconstructed. S .

2. A method for remote voice conversation monitoring based on Rydberg atoms, utilizing the remote voice conversation monitoring device based on Rydberg atoms as described in claim 1, characterized in that, Includes the following steps: Step 1, Detection light K P Adorned with light K D and coupled light K C The rubidium atoms in the rubidium atom gas cell (2) are co-excited to a high Rydberg state, and the frequency of the coupled light is scanned to obtain the EIT spectrum and the EIT resonance point; Step 2, Excite the microwave generator (1) Emits local oscillator microwave K L The local oscillator microwave K is adjusted by passing through the rubidium atom gas cell (2). L The frequency of the coupled light was scanned to the rubidium atom transition resonance point, and the local oscillator microwave K was adjusted. L The power-to-EIT spectrum exhibits the critical state of AT splitting; Step 3, Local Oscillator Microwave K L After being reflected back to the rubidium atom gas cell (2) by the target, the frequency of the coupled light is scanned to obtain the EIT-AT spectrum and vibrational signal K. S The superimposed spectrum; Step 4: Lock the coupling light K C The frequency is at the EIT resonance point, and the vibration signal K is reconstructed. S ; Step 5: Analyze the vibration signal K S Noise reduction, The rubidium atoms in the excited rubidium atom gas chamber (2) are brought to a high Rydberg state based on the following steps: Detector light K P Passing through the rubidium atom gas cell (2), the light is reflected by the polarizing beam splitter (4) to the photodetector (5), exciting the rubidium atoms to the first excited state; the adorned light K D The embellished light K reflected by the beam splitter (7) D The light passes through the polarizing beam splitter (4) and enters the rubidium atom gas cell (2), exciting the rubidium atoms from the first excited state to the intermediate state; the coupled light K... C Reflected by the mirror (8), the particles pass sequentially through the beam splitter (7) and the polarizing beam splitter (4) into the rubidium atom gas chamber (2), exciting the rubidium atoms from the intermediate state to the Gorridberg state. The acquisition of EIT-AT spectrum and vibration signal K S The superimposed spectrum is based on the following steps: Local oscillator microwave K L After passing through the rubidium atom gas chamber (2), it hits the vibrating detection target (3) and is affected by the vibration signal K. S Modulation, to obtain the modulated signal K L +K S Modulation signal K L +K S After reflection, it returns to the rubidium atom gas cell (2), and interacts with the local oscillator microwave K. L The combined action of these atoms induces a difference frequency effect, resulting in the vibrational signal K. S Scan the coupled light frequency to obtain the EIT-AT spectrum and the vibrational signal K sensed by the Rydberg atoms. S Superimposed spectra, The vibration signal K S Noise reduction includes the following steps: Improve the detection light K P Adorned with light K D and coupled light K C Signal-to-noise ratio; Use a bandpass filter to preserve the vocal frequency band; Use Fourier transform or wavelet transform to separate human voice signals. The vibration signal K S Noise reduction also includes the following steps: Separation can be achieved by utilizing blind source separation or independent component analysis, taking advantage of the statistical differences between noise and speech signals. The detection light K P The wavelength is 780nm. The coupled light K C The wavelength is 1260nm. The decorative light K D The wavelength is 776nm.

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