Interferometric measurement system and interferometric measurement method

Abstract

The invention relates to an interference measurement system, an interference measurement method and a controller, which are used for determining a plurality of phase sequences with orthogonal characteristics; the splitter is used for carrying out light splitting processing on a preset reference light source to obtain a reference light signal; the modulator is used for performing phase modulation processing on the received reference light signal according to the plurality of phase sequences to obtain a plurality of modulation signals, and sending the plurality of modulation signals to the optical splitter; the optical splitter is used for carrying out interference processing on the received light field signals and the received modulation signals to obtain a plurality of corresponding interference signals; the plurality of light field signals are obtained by the same target light field through double receiving apertures; and the controller is also used for performing coherence analysis on the plurality of interference signals to obtain a coherence measurement result corresponding to the target light field. On the basis, the system can accurately extract and distinguish light field phase information from different paths, so that high-precision light field coherence measurement can still be realized under a long baseline condition.

Description

Technical Field

[0001] The present application relates to the field of interferometric measurement technology, and in particular to an interferometric measurement system and an interferometric measurement method. Background Art

[0002] Traditional Hanbury Brown-Twiss (HBT) interferometry, which measures the second-order coherence of light fields through intensity correlation analysis, has important applications in astronomical observations, quantum optics, and other fields. However, the traditional HBT method cannot accurately measure the phase characteristics of light fields, limiting its application in applications such as synthetic aperture imaging and precision ranging, which require a complete characterization of the complex coherence function. In particular, in long-baseline optical systems, phase noise introduced by factors such as atmospheric turbulence and mechanical vibration can significantly reduce measurement accuracy.

[0003] There is currently no effective solution to the phase insensitivity problem of traditional HBT interferometry technology under long baseline conditions. Summary of the Invention

[0004] Based on this, it is necessary to provide an interference measurement system and an interference measurement method to address the above technical problems.

[0005] In a first aspect, the present application provides an interferometry system, the system comprising a spatially separated dual receiving aperture, a splitter, an optical splitter, a modulator, and a controller; wherein,

[0006] The controller is configured to determine a plurality of phase sequences having an orthogonal characteristic and send the plurality of phase sequences to the modulator;

[0007] The splitter is used to perform light splitting processing on a preset reference light source to obtain a reference light signal, and send the reference light signal to the modulator;

[0008] The modulator is configured to perform phase modulation processing on the received reference optical signal according to the multiple phase sequences to obtain multiple modulated signals, and send the multiple modulated signals to the optical splitter;

[0009] The optical splitter is used to perform interference processing on the received multiple light field signals and the multiple modulated signals to obtain corresponding multiple interference signals; the multiple light field signals are obtained by the same target light field passing through the dual receiving apertures;

[0010] The controller is further configured to perform coherence analysis on the plurality of interference signals to obtain a coherence measurement result corresponding to the target light field.

[0011] In one embodiment, the light field signal includes a first light field signal and a second light field signal; the dual receiving aperture includes a first receiving aperture and a second receiving aperture; the first receiving aperture and the second receiving aperture are spatially separated;

[0012] The first receiving aperture is used to receive the first light field signal reflected by the target light field;

[0013] The second receiving aperture is used to receive a second light field signal reflected by the target light field.

[0014] In one embodiment, the system further comprises a delay device;

[0015] The delay device is used to perform delay processing on the received first light field signal to obtain a delayed signal.

[0016] In one embodiment, the phase sequence includes a first phase sequence and a second phase sequence; the reference optical signal includes a first reference optical signal and a second reference optical signal; the modulator includes a first modulator, a second modulator, and a third modulator;

[0017] The first modulator is configured to perform phase modulation processing on the received first reference optical signal according to the first phase sequence to obtain a first modulated signal;

[0018] The second modulator is configured to perform phase modulation processing on the received second reference optical signal according to the second phase sequence to obtain a second modulated signal;

[0019] The third modulator is configured to perform phase modulation on the first modulated signal to obtain a third modulated signal;

[0020] or,

[0021] The third modulator is used to perform phase modulation on the second modulation signal to obtain a fourth modulation signal.

[0022] In one embodiment, the optical field signal includes a first optical field signal and a second optical field signal; the optical splitter includes a first sub-splitter and a second sub-splitter;

[0023] The first sub-splitter is configured to perform interference processing on the received delayed signal and the first modulated signal to obtain a first interference signal;

[0024] The second sub-splitter is configured to perform interference processing on the received second light field signal and the fourth modulated signal to obtain a second interference signal.

[0025] In one embodiment, the optical field signal includes a first optical field signal and a second optical field signal; the optical splitter includes a first sub-splitter and a second sub-splitter;

[0026] The first sub-splitter is configured to perform interference processing on the received delayed signal and the third modulated signal to obtain a first interference signal;

[0027] The second sub-splitter is configured to perform interference processing on the received second light field signal and the second modulated signal to obtain a second interference signal.

[0028] In one embodiment, the system further comprises a first detector and a second detector; the controller comprises a first subtractor, a second subtractor, a multiplier, an integrator, and a signal processor;

[0029] The first subtractor is configured to perform differential processing on the first interference signal received by the first detector to obtain a first differential signal;

[0030] The second subtractor is configured to perform differential processing on the second interference signal received by the second detector to obtain a second differential signal;

[0031] The multiplier is configured to perform a multiplication operation on the first differential signal and the second differential signal to obtain a first correlation result;

[0032] The integrator is configured to perform a periodic inner product operation on the first correlation result to obtain a second correlation result;

[0033] The signal processor is used to perform spectrum analysis on the second correlation result to obtain a coherence measurement result corresponding to the target light field; the coherence measurement result includes an amplitude measurement result and a phase measurement result.

[0034] In a second aspect, the present application further provides an interferometry method, which is applied to the interferometry system described in any one of the embodiments of the first aspect above; the system includes spatially separated dual receiving apertures, a splitter, a spectrometer, a modulator, and a controller; the method includes:

[0035] Determining a plurality of phase sequences having an orthogonal characteristic, sending the plurality of phase sequences to the modulator, so that the modulator performs phase modulation processing on the received reference optical signal according to the plurality of phase sequences to obtain a plurality of modulated signals, and sending the plurality of modulated signals to the optical splitter;

[0036] receiving a plurality of interference signals sent by the optical splitter; the plurality of interference signals are determined after the optical splitter performs interference processing on the plurality of received light field signals and the plurality of modulated signals; the light field signals are obtained by passing the same target light field through the dual receiving apertures;

[0037] Coherence analysis is performed on the multiple interference signals to obtain a coherence measurement result corresponding to the target light field.

[0038] In one embodiment, the interference signal includes a first interference signal and a second interference signal; and performing coherence analysis on the plurality of interference signals to obtain a coherence measurement result corresponding to the target light field includes:

[0039] performing differential processing on the first interference signal and the second interference signal respectively to obtain a first differential signal and a second differential signal;

[0040] A correlation calculation is performed on the first differential signal and the second differential signal to obtain a coherence measurement result corresponding to the target light field.

[0041] In one embodiment, the coherence measurement result includes an amplitude measurement result and a phase measurement result; and performing correlation calculation on the first differential signal and the second differential signal to obtain the coherence measurement result corresponding to the target light field includes:

[0042] performing a multiplication operation on the first differential signal and the second differential signal to obtain a first correlation result;

[0043] performing a periodic inner product operation on the first correlation result to obtain a second correlation result;

[0044] Performing spectrum analysis on the second correlation result to obtain an amplitude measurement result and a phase measurement result corresponding to the target light field.

[0045] In a third aspect, the present application further provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps of the method described in any one of the above embodiments are implemented.

[0046] In a fourth aspect, the present application further provides a computer program product, comprising a computer program, which, when executed by a processor, implements the steps of the method described in any one of the above embodiments.

[0047] The above-mentioned interference measurement system and interference measurement method, wherein the system includes a spatially separated dual receiving aperture, a splitter, a splitter, a modulator and a controller; wherein the controller is used to determine multiple phase sequences with orthogonal characteristics and send the multiple phase sequences to the modulator; based on the phase sequences with orthogonal characteristics, it lays the foundation for the system to effectively separate signals in the subsequent signal processing stage, improve the signal-to-noise ratio, and achieve a greater measurement contrast; the splitter is used to perform spectroscopic processing on a preset reference light source to obtain a reference light signal, and send the reference light signal to the modulator; based on the preset reference light source, there is no need to establish a complex quantum entanglement network, which effectively reduces the complexity of the interference measurement system and lays the foundation for further improving the applicability of the interference measurement system; the modulator is used to perform phase modulation processing on the received reference light signal according to multiple phase sequences to obtain The system receives multiple modulated signals and sends the multiple modulated signals to the spectrometer; the spectrometer is used to perform interference processing on the received multiple light field signals and multiple modulated signals to obtain corresponding multiple interference signals; the multiple light field signals are obtained by the same target light field through a dual receiving aperture; multiple interference signals are obtained by performing interference processing on multiple modulated signals and multiple light field signals, which lays the foundation for realizing coherence measurement of light field signals of different paths; the controller is also used to perform coherence analysis on the multiple interference signals to obtain coherence measurement results corresponding to the target light field; based on this, the system can accurately extract and distinguish the light field phase information from different paths, so that high-precision light field coherence measurement can still be achieved under long baseline conditions, which greatly expands the application range and reliability of interferometric measurement and effectively avoids the problem of phase insensitivity of traditional HBT interferometry systems under long baseline conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following briefly introduces the drawings required for use in the embodiments of the present application or related technical descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying any creative work.

[0049] Figure 1 Schematic diagram of the overall structure of an interferometric measurement system in one embodiment;

[0050] Figure 2 Schematic diagram of the overall structure of the interference measurement system in the first embodiment;

[0051] Figure 3 Schematic diagram of the overall structure of the interference measurement system in the second embodiment;

[0052] Figure 4 Schematic diagram of the overall structure of an interferometric measurement system according to a specific embodiment;

[0053] Figure 5 1 is a flow chart of an interferometry method according to an embodiment;

[0054] Figure 6a In one embodiment, the delay time is τ=-4×10 -15 Seconds, flow chart of the relationship between the intensity correlation function and the phase modulation θ;

[0055] Figure 6b In one embodiment, the delay time is τ=-2×10 -15 Seconds, a flow chart showing the relationship between the intensity correlation function and the phase modulation θ;

[0056] Figure 6c Schematic diagram of a flow chart showing a relationship between an intensity correlation function and a phase modulation θ when the delay time is τ=0 seconds in one embodiment;

[0057] Figure 6d In one embodiment, the delay time is τ=2×10 -15 Seconds, flow chart of the relationship between the intensity correlation function and the phase modulation θ;

[0058] Figure 6e In one embodiment, the delay time is τ=4×10 -15 Seconds, flow chart of the relationship between the intensity correlation function and the phase modulation θ;

[0059] Figure 7 is a schematic diagram of an envelope function in one embodiment;

[0060] Figure 8 Schematic diagram of a phase difference function in one embodiment. DETAILED DESCRIPTION

[0061] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0062] Optical synthetic aperture technology is a high-resolution imaging method developed following its successful application in radio astronomy. It is of great value in astronomical observations, space target monitoring, and lidar. Compared to radio bands, optical bands, due to their short wavelength and high frequency, can achieve higher spatial resolution, but also place more stringent requirements on phase control. In optical long-baseline multi-aperture synthetic imaging systems, the operating wavelength is typically in the visible to near-infrared range (400-1000 nanometers), requiring phase control accuracy at the subwavelength level.

[0063] Related technologies face three core challenges: First, refractive index fluctuations caused by atmospheric turbulence lead to random variations in optical path difference, and the perturbation effect is exponentially amplified over long-distance transmission; second, micron-level deformations caused by factors such as mechanical vibration and thermal expansion can produce phase errors of several wavelengths; and third, multi-aperture coherent synthesis requires optical path difference control accuracy at the picometer level. Traditional HBT (Hanbury Brown-Twiss) interferometry technology can only measure intensity correlations and cannot obtain phase information. This is severely limited in scenarios such as synthetic aperture imaging and precision ranging that require complete complex coherence function characterization. Especially under long baseline conditions, phase noise introduced by atmospheric turbulence and mechanical vibration can significantly degrade system performance.

[0064] In response to the problem of phase insensitivity of traditional HBT interferometry systems under long baseline conditions in traditional HBT interferometry technology, the present application provides an interferometry measurement system that achieves high-precision measurement of the phase characteristics of the light field under long baseline conditions through spatially separated dual receiving apertures combined with a spectrometer, a modulator and a controller.

[0065] In one embodiment, Figure 1 As shown, Figure 1 FIG. 1 is a schematic diagram of the overall structure of an interferometric measurement system in one embodiment; the interferometric measurement system includes a spatially separated dual receiving aperture 100, a splitter 200, a beam splitter 300, a modulator 400, and a controller 500; wherein,

[0066] The controller 500 is configured to determine a plurality of phase sequences having an orthogonal characteristic and send the plurality of phase sequences to the modulator 400 (the transmission paths of the plurality of phase sequences are not shown in the figure);

[0067] The splitter 200 is used to split the preset reference light source to obtain a reference light signal, and send the reference light signal to the modulator 400;

[0068] The modulator 400 is configured to perform phase modulation processing on the received reference optical signal according to multiple phase sequences to obtain multiple modulated signals, and send the multiple modulated signals to the optical splitter 300;

[0069] The optical splitter 300 is used to perform interference processing on the received multiple light field signals and multiple modulated signals to obtain corresponding multiple interference signals; the multiple light field signals are obtained by the same target light field passing through the dual receiving apertures 100;

[0070] The controller 500 is further configured to perform coherence analysis on the multiple interference signals to obtain coherence measurement results corresponding to the target light field.

[0071] Among them, the spatially separated dual receiving aperture 100 includes a first receiving aperture and a second receiving aperture. The first receiving aperture and the second receiving aperture are spatially separated, that is, the distance between the first receiving aperture and the second receiving aperture can reach hundreds of meters or even longer, laying the foundation for realizing long-baseline interferometry.

[0072] The target light field can be a star or other observed object, and is not specifically limited here. It is understood that the interferometry system in this embodiment can be used in fields such as weak-light target detection in astronomical observations, phase measurement in large-aperture optical telescopes, active or passive imaging of space targets, optical imaging under atmospheric turbulence conditions, and optical coherence tomography. The choice of target light field depends on the actual application scenario and is not specifically limited here.

[0073] The light field signal includes a first light field signal and a second light field signal. The light field signal is a broadband optical signal with a very short coherence length. It can be understood that the light field signal carries information about photons arriving at the first receiving aperture or the second receiving aperture from a specific direction or path.

[0074] The controller 500 is provided with a DSP (Digital Signal Processor) for realizing signal analysis and processing.

[0075] The phase sequence can be a pseudo-random binary sequence, which is not specifically limited here; the phase sequence includes a first phase sequence and a second phase sequence, and the first phase sequence and the second phase sequence have strict orthogonality; for example, the first phase sequence is denoted as λ(1), and the second phase sequence is denoted as λ(2), and the mutual correlation within the period of the first phase sequence λ(1) and the second phase sequence λ(2) is zero, that is: ∫λ(1)(t)·λ(2)(t)dt=0; the autocorrelation of the first phase sequence λ(1) and the second phase sequence λ(2) has an ideal pulse characteristic, that is: ∫λ(t)(t)·λ(i)(t)dt=1(i=1,2).

[0076] It should be noted that the multiple phase sequences may be generated by the controller 500 or may be generated by an external terminal and then transmitted to the controller 500 , which is not specifically limited here.

[0077] The splitter 200 is used to perform splitting processing on a preset reference light source. The preset reference light source is an ordinary coherent light source, which can be, but is not limited to, a classical light field, a continuous wave, and a pulsed light field, and is not specifically limited here.

[0078] Understandably, traditional methods rely on quantum entangled light sources, making them extremely difficult to implement. This embodiment uses a conventional coherent light source as the reference light, significantly reducing the complexity. Conventional coherent light sources, such as classical light fields, are much easier to obtain than quantum entangled light sources, effectively reducing system complexity.

[0079] The modulator 400 is used to implement phase modulation processing on multiple optical field signals based on multiple phase sequences with orthogonal characteristics. The modulator 400 may include, but is not limited to, an electro-optical phase modulator, which is not specifically limited here.

[0080] It can be understood that since each phase sequence is unique and orthogonal to other phase sequences, each modulated signal carries unique information. Even if the signals interfere and overlap during transmission, they can be separated based on their unique phase sequence characteristics.

[0081] The optical splitter 300 includes a first sub-splitter and a second sub-splitter. The first sub-splitter and the second sub-splitter may be 50 / 50 splitters, which are not specifically limited here. The optical splitter 300 is used to achieve interference mixing of the optical field signal and the modulated signal.

[0082] Exemplarily, it is assumed that the preset reference light source is generated by a laser; based on the interferometric measurement system, a first light field signal and a second light field signal from the target light field are received respectively through a spatially separated first receiving aperture and a second receiving aperture; based on the splitter 200, the preset reference light source is subjected to optical splitting processing to obtain a first reference light signal and a second reference light signal, and the first reference light signal and the second reference light signal are sent to the modulator 400 respectively; through the modulator 400, the first reference light signal and the second reference light signal are subjected to corresponding phase modulation processing respectively according to a first phase sequence and a second phase sequence with orthogonal characteristics to obtain multiple modulated signals, including a first modulated signal and a second modulated signal; then, based on the spectrometer 300, the first modulated signal and the first light field signal, and the second modulated signal and the second light field signal are subjected to corresponding interference aliasing processing respectively to obtain a first interference signal and a second interference signal; wherein the first interference signal and the second interference signal carry different phase information; further, based on the controller 500, the first interference signal and the second interference signal are subjected to coherence analysis to obtain a coherence measurement result corresponding to the target light field.

[0083] In this embodiment, a phase sequence with orthogonal characteristics is determined by the controller 500, which lays the foundation for the system to effectively separate signals in the subsequent signal processing stage, improve the signal-to-noise ratio, and achieve a greater measurement contrast; the preset reference light source is split by the splitter 200 to obtain a reference light signal; based on the preset reference light source, there is no need to establish a complex quantum entanglement network, which effectively reduces the complexity of the interference measurement system and lays the foundation for further improving the applicability of the interference measurement system; the modulator 400 is used to phase modulate the received reference light signal according to multiple phase sequences to obtain multiple modulated signals, and the multiple modulated signals are sent to the splitter. optical device; then, based on the spectrometer 300, the received multiple light field signals and multiple modulated signals are interfered with to obtain corresponding multiple interference signals; this lays the foundation for realizing the coherence measurement of light field signals in different paths; finally, the controller 500 performs coherence analysis on the multiple interference signals to obtain the coherence measurement results corresponding to the target light field; based on this, the system can accurately extract and distinguish the light field phase information from different paths, so that high-precision light field coherence measurement can still be achieved under long baseline conditions, which greatly expands the application range and reliability of interferometry measurement and effectively avoids the problem of phase insensitivity of traditional HBT interferometry systems under long baseline conditions.

[0084] In one embodiment, Figure 2 or Figure 3 As shown, the light field signal includes a first light field signal and a second light field signal; the dual receiving aperture 100 includes a first receiving aperture and a second receiving aperture; the first receiving aperture and the second receiving aperture are spatially separated;

[0085] A first receiving aperture is used to receive a first light field signal reflected by a target light field;

[0086] The second receiving aperture is used to receive the second light field signal reflected by the target light field.

[0087] Both the first and second light field signals are broadband optical signals with very short coherence lengths. It can be understood that the first light field signal carries information about photons arriving at the first receiving aperture from a specific direction or path, while the second light field signal carries information about photons arriving at the second receiving aperture from a specific direction or path.

[0088] In this embodiment, the spatially separated first receiving aperture and the second receiving aperture can receive the first light field signal and the second light field signal reflected from different paths of the target light field, laying the foundation for achieving interferometric measurement under long baseline conditions.

[0089] In one embodiment, Figure 2 or Figure 3 As shown, the system further includes a delay device 600;

[0090] The delayer 600 is used to perform delay processing on the received first light field signal to obtain a delayed signal.

[0091] The delay device 600 may, but is not limited to, adopt a piezoelectric ceramic telescopic mirror structure with a resolution of up to 0.1 nm, and needs to be set according to the actual needs of the interferometric measurement, which is not specifically limited here.

[0092] It is understood that the delay device 600 can be used to compensate for the optical path difference between the first light field signal and the first phase sequence, ensuring synchronization between the two signals and allowing the first light field signal and the first phase sequence to overlap within the time window. Furthermore, the delay device 600 is used to introduce a controllable time delay for interferometry.

[0093] In this embodiment, based on the delay device 600, the synchronization between the first light field signal and the first phase sequence is ensured, and a controllable time delay can be introduced, laying a foundation for realizing interference measurement.

[0094] In one embodiment, Figure 2 or Figure 3 As shown, the phase sequence includes a first phase sequence and a second phase sequence; the reference optical signal includes a first reference optical signal and a second reference optical signal; the modulator 400 includes a first modulator, a second modulator and a third modulator;

[0095] A first modulator is configured to perform phase modulation processing on the received first reference optical signal according to a first phase sequence to obtain a first modulated signal;

[0096] a second modulator, configured to perform phase modulation processing on the received second reference optical signal according to a second phase sequence to obtain a second modulated signal;

[0097] a third modulator, configured to perform phase modulation on the first modulated signal to obtain a third modulated signal;

[0098] or,

[0099] The third modulator is used to perform phase modulation on the second modulation signal to obtain a fourth modulation signal.

[0100] Among them, the first modulator and the second modulator can be but are not limited to electro-optical modulators, which are used to perform preliminary phase modulation processing on the first reference optical signal and the second reference optical signal based on the first phase sequence and the second phase sequence with orthogonal characteristics to obtain the first modulated signal and the second modulated signal, ensure that the first modulated signal and the second modulated signal are independent of each other in the phase space, reduce interference between the signals, and improve the efficiency and accuracy of information transmission.

[0101] The third modulator is an adjustable phase modulator for introducing a controllable phase change. It is understood that the third modulator can apply a precise phase offset to the first or second modulated signal. The phase offset can be dynamically adjusted based on, but is not limited to, a PID control algorithm.

[0102] Optional, see Figure 2 In a first exemplary embodiment, the first sub-splitter is configured to perform interference processing on the received delayed signal and the first modulated signal to obtain a first interference signal;

[0103] The second sub-splitter is used to perform interference processing on the received second light field signal and the fourth modulated signal to obtain a second interference signal.

[0104] Optional, see Figure 3 , in a second exemplary embodiment, the first sub-splitter is configured to perform interference processing on the received delayed signal and the third modulated signal to obtain a first interference signal;

[0105] The second sub-splitter is used to perform interference processing on the received second light field signal and the second modulated signal to obtain a second interference signal.

[0106] It is understandable that the configuration of the third modulator needs to be set according to actual system requirements and is not specifically limited here.

[0107] In this embodiment, a first modulator and a second modulator perform preliminary phase modulation on a first reference optical signal and a second reference optical signal having orthogonal characteristics, ensuring that the generated first and second modulated signals are independent of each other in phase space. This effectively reduces interference between the signals and improves the efficiency and accuracy of information transmission. A third modulator, acting as an adjustable phase modulator, can apply a precise, controllable phase offset to either the first or second modulated signal, paving the way for phase measurement of the correlation function. This phase offset can be dynamically adjusted using methods such as a PID control algorithm to accommodate different application requirements. Furthermore, the different configurations of the third modulator effectively enhance the flexibility and adaptability of the system.

[0108] In one embodiment, the system further includes a first detector and a second detector; the controller 500 includes a first subtractor, a second subtractor, a multiplier, an integrator, and a signal processor;

[0109] a first subtractor, configured to perform differential processing on the first interference signal received by the first detector to obtain a first differential signal;

[0110] a second subtractor, configured to perform differential processing on the second interference signal received by the second detector to obtain a second differential signal;

[0111] a multiplier, configured to perform a multiplication operation on the first differential signal and the second differential signal to obtain a first correlation result;

[0112] an integrator, configured to perform a periodic inner product operation on the first correlation result to obtain a second correlation result;

[0113] The signal processor is used to perform spectrum analysis on the second correlation result to obtain a coherence measurement result corresponding to the target light field; the coherence measurement result includes an amplitude measurement result and a phase measurement result.

[0114] The first detector and the second detector may be, but are not limited to, photoelectric detectors, for receiving corresponding interference signals and converting the interference signals into electrical signals for subsequent signal processing based on the controller 500 .

[0115] It can be understood that the first detector and the second detector are electrically connected to the controller 500 .

[0116] The first subtractor and the second subtractor are used to perform differential processing on the corresponding interference signals, eliminate common mode noise, and improve the signal-to-noise ratio.

[0117] The first correlation result primarily reflects the direct cross-correlation between the two interfering signals and is the basis for understanding the interaction between the signals. The second correlation result, based on this, integrates the first correlation result to remove noise and stabilize the signal, providing high-quality data support for the final spectrum analysis and coherence measurement.

[0118] The coherence measurement results include amplitude measurement results and phase measurement results. The amplitude measurement results are used to characterize the intensity characteristics of the signal, and the phase measurement results are used to characterize the temporal or spatial relationship between the signals. Exemplarily, the amplitude measurement results include an intensity correlation function.

[0119] In this embodiment, differential processing of the received interference signal using the first and second subtractors effectively eliminates common-mode noise and improves the signal-to-noise ratio. Further processing through components such as the multiplier and integrator enhances the system's anti-interference capability, ensuring clear and reliable measurement results even in complex environments.

[0120] In one embodiment, see Figure 4, assuming that the preset reference light source is generated by a laser; based on the interferometric measurement system, a first light field signal V(r1) and a second light field signal V(r1) from the target light field are received respectively through a spatially separated first receiving aperture and a second receiving aperture; the preset reference light source is subjected to optical splitting processing through a splitter to obtain a first reference light signal and a second reference light signal; the first reference light signal is sent to a first modulator, and the first modulator performs phase modulation processing on the received first reference light signal according to a first phase sequence to obtain a first modulated signal; the second reference light signal is sent to a second modulator, and the second modulator performs phase modulation processing on the received second reference light signal according to a second phase sequence orthogonal to the first phase sequence to obtain a second modulated signal; further, the second modulated signal is phase modulated by a third modulator to obtain a fourth modulated signal. Furthermore, through the first sub-splitter, the delayed signal obtained by delaying the first light field signal V(r1) received by the delay device is interfered with the first modulated signal to obtain a first interference signal; through the second sub-splitter, the second light field signal received and the fourth modulated signal are interfered with to obtain a second interference signal.

[0121] Furthermore, a first subtractor is used to perform differential processing on the first interference signal received by the first detector to obtain a first differential signal; a second subtractor is used to perform differential processing on the second interference signal received by the second detector to obtain a second differential signal; a multiplier is used to multiply the first differential signal and the second differential signal to obtain a first correlation result; an integrator is used to perform a periodic inner product operation on the first correlation result to obtain a second correlation result; finally, a signal processor is used to perform spectral analysis on the second correlation result to obtain a coherence measurement result corresponding to the target light field; wherein the coherence measurement result includes an amplitude measurement result and a phase measurement result.

[0122] The above-mentioned interferometry measurement system can accurately extract and distinguish the light field phase information from different paths, so that high-precision light field coherence measurement can still be achieved under long baseline conditions, which greatly expands the application range and reliability of interferometry and effectively avoids the phase insensitivity problem of traditional HBT interferometry systems under long baseline conditions.

[0123] In one embodiment, Figure 5 As shown, Figure 5 1 is a flow chart of an interferometry method in one embodiment; the interferometry method of this embodiment is applied to the interferometry system described in any of the above embodiments; the interferometry system includes spatially separated dual receiving apertures, a splitter, a beam splitter, a modulator, and a controller; the interferometry method includes the following steps:

[0124] Step S501: determine multiple phase sequences with orthogonal characteristics, send the multiple phase sequences to the modulator, so that the modulator performs phase modulation processing on the received reference optical signal according to the multiple phase sequences to obtain multiple modulated signals, and send the multiple modulated signals to the optical splitter.

[0125] Among them, the functions and effects of each component in the interference measurement system are the same as those described in the above embodiment and will not be repeated here.

[0126] The phase sequence can be a pseudo-random binary sequence, which is not specifically limited here; the phase sequence includes a first phase sequence and a second phase sequence, and the first phase sequence and the second phase sequence have strict orthogonality; for example, the first phase sequence is denoted as λ(1), and the second phase sequence is denoted as λ(2), and the mutual correlation within the period of the first phase sequence λ(1) and the second phase sequence λ(2) is zero, that is: ∫λ(1)(t)·λ(2)(t)dt=0; the autocorrelation of the first phase sequence λ(1) and the second phase sequence λ(2) has an ideal pulse characteristic, that is: ∫λ(i)(t)·λ(i)(t)dt=1(i=1,2).

[0127] It should be noted that the multiple phase sequences may be generated by the controller, or may be generated by an external terminal and then transmitted to the controller, which is not specifically limited here.

[0128] The reference optical signal includes a first reference optical signal and a second reference optical signal; the reference optical signal is obtained after the splitter performs optical splitting processing on a preset reference light source; the preset reference light source is an ordinary coherent light source, which can be, but is not limited to, from a classical light field, a continuous wave, and a pulsed light field, and is not specifically limited here.

[0129] Understandably, traditional methods rely on quantum entangled light sources, making them extremely difficult to implement. This embodiment uses a conventional coherent light source as the reference light, significantly reducing the complexity. Conventional coherent light sources, such as classical light fields, are much easier to obtain than quantum entangled light sources, effectively reducing system complexity.

[0130] Step S502: receiving a plurality of interference signals sent by the optical splitter.

[0131] The multiple interference signals are determined after the optical splitter performs interference processing on the multiple received light field signals and the multiple modulated signals. The light field signals are obtained by passing the same target light field through the dual receiving apertures.

[0132] It can be understood that since each phase sequence is unique and orthogonal to other sequences, each modulated signal carries unique information. Even if the signals interfere and overlap during transmission, they can be separated based on their unique phase sequence characteristics.

[0133] Step S503 : performing coherence analysis on the multiple interference signals to obtain a coherence measurement result corresponding to the target light field.

[0134] The coherence measurement results include amplitude measurement results and phase measurement results. The amplitude measurement results are used to characterize the intensity characteristics of the signal; the phase measurement results are used to characterize the temporal or spatial relationship between signals.

[0135] In this embodiment, based on multiple phase sequences with orthogonal characteristics, the system lays the foundation for effectively separating signals, improving the signal-to-noise ratio, and achieving greater measurement contrast in the subsequent signal processing stage; based on the preset reference light source, there is no need to establish a complex quantum entanglement network, which effectively reduces the complexity of the interference measurement system and lays the foundation for further improving the applicability of the interference measurement system; by performing coherence analysis on multiple interference signals, the coherence measurement results corresponding to the target light field are obtained; based on this, the system can accurately extract and distinguish the light field phase information from different paths, so that high-precision light field coherence measurement can still be achieved under long baseline conditions, which greatly expands the application scope and reliability of interference measurement and effectively avoids the problem of phase insensitivity of traditional HBT interference systems under long baseline conditions.

[0136] In one embodiment, the interference signal includes a first interference signal and a second interference signal; performing coherence analysis on the multiple interference signals to obtain a coherence measurement result corresponding to the target light field includes the following steps:

[0137] Step 1: Perform differential processing on the first interference signal and the second interference signal to obtain a first differential signal and a second differential signal.

[0138] Step 2: perform correlation calculation on the first differential signal and the second differential signal to obtain a coherence measurement result corresponding to the target light field.

[0139] Preferably, performing correlation calculation on the first differential signal and the second differential signal in step 2 to obtain a coherence measurement result corresponding to the target light field includes the following steps:

[0140] Step 2.1: Perform a multiplication operation on the first differential signal and the second differential signal to obtain a first correlation result.

[0141] Step 2.2, performing a periodic inner product operation on the first correlation result to obtain a second correlation result;

[0142] Step 2.3: Perform spectrum analysis on the second correlation result to obtain the amplitude measurement result and phase measurement result corresponding to the target light field.

[0143] The first correlation result primarily reflects the direct cross-correlation between the two interfering signals and is the basis for understanding the interaction between the signals. The second correlation result, based on this, integrates the first correlation result to remove noise and stabilize the signal, providing high-quality data support for the final spectrum analysis and coherence measurement.

[0144] It should be noted that the specific implementation of the above-mentioned difference processing, multiplication operation, periodic inner product operation and spectrum analysis is the same as the traditional implementation, and will not be described in detail here.

[0145] In this embodiment, by performing differential processing on the received interference signal, common-mode noise can be effectively eliminated and the signal-to-noise ratio can be improved. Furthermore, by performing a series of processing such as multiplication operations, periodic inner product operations, and spectrum analysis on the differential signal, clear and reliable measurement results can be obtained even in complex environments.

[0146] In some specific applications, the coherence measurement results include the intensity correlation function, which is used to analyze the second-order coherence of the target light field. For a time-dependent light field E(t), the intensity correlation function is defined as: g (2) (π)=<I(t)I(t+τ)> / <I(t)><I(t+τ)> ;in,<I(t)I(t+τ)> , represents the time average of the product of the light intensities measured at different time points t and t+τ;<I(t)> and<I(t+τ)> , respectively represent the time average of the light intensity measured at these time points.

[0147] Based on the interferometry system and interferometry method described in the above embodiments, by dynamically adjusting the delay time of the delay device and the phase modulation θ of the third modulator, the relationship between the intensity correlation function and the phase modulation θ under different delay conditions can be obtained; for example, as shown in FIG6 , Figures 6a to 6e The corresponding delay τ is -4×10 -15 seconds, τ = -2 × 10 -15 seconds, τ = 0 seconds, τ = 2 × 10 -15 seconds, τ = 4 × 10 -15 The relationship between the intensity correlation function and the phase modulation θ when . Figures 6a to 6e In the figure, the horizontal axis represents the phase modulation θ, and the vertical axis represents the correlation intensity.

[0148] Furthermore, based on the relationship diagram between the intensity correlation function and the phase modulation θ shown in FIG6 , the envelope function and the phase difference function of the first light field signal and the second light field signal can be obtained, as shown in FIG6 . Figure 7 and Figure 8 shown. Figure 7 The ordinate represents the amplitude of the intensity correlation function, and the abscissa represents the delay τ; Figure 8 The vertical axis represents the phase, and the horizontal axis represents the delay τ.

[0149] Exemplarily, a specific method for calculating the phase difference and envelope of the first light field signal and the second light field signal includes the following steps:

[0150] Step 1: Fit the relationship curve between the intensity correlation function and the phase modulation θ at each time delay to obtain the target fitting function.

[0151] Among them, the expression of the target fitting function is: Among them, A(T) is the bias term, B(T) is the amplitude, is the phase difference, and θ is the phase of the third modulator.

[0152] Step 2: extract the amplitude of each target fitting function respectively to obtain multiple target amplitudes, and obtain the envelope function based on the multiple target amplitudes.

[0153] Among them, the envelope function reflects the mutual coherence between the first light field signal and the second light field signal, which is expressed by γ(T) = B(T) / B(0); when γ(T) ≈ 1, it means that the first light field signal and the second light field signal have strong coherence under the delay T; when γ(T) tends to 0, it means that the coherence of the two light fields gradually weakens or even disappears.

[0154] Step 3: extract the phase term of each target fitting function respectively to obtain multiple target phase terms, and determine the phase difference function based on the multiple target phase terms.

[0155] It can be understood that the envelope function reflects the coherence characteristics of the light field, while the phase difference function reflects the dispersion characteristics of the light field; these two functions are of great significance for understanding the spatiotemporal characteristics of the light field.

[0156] In another exemplary embodiment, the phase difference function may be determined by observing the zero point position of the waveform, calculating the phase offset relative to T=0 μs, and obtaining the phase difference function under different delays.

[0157] In some of these embodiments, a single-photon entangled state can be used to replace the preset reference light source, a perfect anti-bunching light field can be used as the preset reference light source, a modified coherent state (eliminating the two-photon term by destructive two-photon interference) can be used as the preset reference light source, or an anti-bunching light field generated by a single emitter can be used as the preset reference light source.

[0158] The above-mentioned interference measurement system has achieved an important expansion of the traditional HBT interferometer, enabling it to have phase-sensitive measurement capabilities. Through the coding modulation of the orthogonal phase sequence, it has achieved effective signal separation and noise suppression, and can measure the complete complex coherence function of the target light field, including amplitude information and phase information, and does not require the two received signals (i.e., the first light field signal and the second light field signal) to directly interfere, which reduces the difficulty of technical implementation. At the same time, using an ordinary coherent state as a reference light field, there is no need for a complex quantum entanglement source, reducing the complexity of the system. At the same time, the above-mentioned interference measurement system can be used in astronomical observation and long-range target detection, long-baseline interferometry, optical imaging under atmospheric turbulence conditions, optical coherence tomography and other fields.

[0159] It should be understood that, although the various steps in the flowcharts involved in the various embodiments described above are displayed in sequence according to the instructions of the arrows, these steps are not necessarily executed in sequence in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps can be executed in other orders. Moreover, at least a portion of the steps in the flowcharts involved in the various embodiments described above can include multiple steps or multiple stages, and these steps or stages are not necessarily executed and completed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a portion of steps or stages in other steps.

[0160] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0161] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0162] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, database or other media used in the embodiments provided in this application may include at least one of non-volatile memory and volatile memory. Non-volatile memory may include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory may include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in the various embodiments provided herein may include at least one of a relational database and a non-relational database. Non-relational databases may include, but are not limited to, distributed databases based on blockchains. The processor involved in the various embodiments provided herein may be, but are not limited to, a general-purpose processor, a central processing unit (CPU), a graphics processing unit (GPU), a digital signal processor (DSP), a programmable logic unit (PLC), a data processing logic unit based on quantum computing, an artificial intelligence (AI) processor, and the like.

[0163] The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0164] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. An interferometric measurement system, characterized in that: The system includes spatially separated dual receiving apertures, a splitter, an optical splitter, a modulator, and a controller; wherein, The controller is configured to determine a plurality of phase sequences having an orthogonal characteristic and send the plurality of phase sequences to the modulator; The splitter is used to perform light splitting processing on a preset reference light source to obtain a reference light signal, and send the reference light signal to the modulator; The modulator is configured to perform phase modulation processing on the received reference optical signal according to the multiple phase sequences to obtain multiple modulated signals, and send the multiple modulated signals to the optical splitter; The optical splitter is used to perform interference processing on the received multiple light field signals and the multiple modulated signals to obtain corresponding multiple interference signals; the multiple light field signals are obtained by the same target light field passing through the dual receiving apertures; The controller is further configured to perform coherence analysis on the plurality of interference signals to obtain a coherence measurement result corresponding to the target light field.

2. The system according to claim 1, wherein: The light field signal includes a first light field signal and a second light field signal; the dual receiving aperture includes a first receiving aperture and a second receiving aperture; the first receiving aperture and the second receiving aperture are spatially separated; The first receiving aperture is used to receive the first light field signal reflected by the target light field; The second receiving aperture is used to receive a second light field signal reflected by the target light field.

3. The system according to claim 1, wherein: The system further comprises a time delay device; The delay device is used to perform delay processing on the received first light field signal to obtain a delayed signal.

4. The system according to claim 3, characterized in that The phase sequence includes a first phase sequence and a second phase sequence; the reference optical signal includes a first reference optical signal and a second reference optical signal; the modulator includes a first modulator, a second modulator and a third modulator; The first modulator is configured to perform phase modulation processing on the received first reference optical signal according to the first phase sequence to obtain a first modulated signal; The second modulator is configured to perform phase modulation processing on the received second reference optical signal according to the second phase sequence to obtain a second modulated signal; The third modulator is configured to perform phase modulation on the first modulated signal to obtain a third modulated signal; or, The third modulator is used to perform phase modulation on the second modulation signal to obtain a fourth modulation signal.

5. The system according to claim 4, characterized in that The optical field signal includes a first optical field signal and a second optical field signal; the optical splitter includes a first sub-splitter and a second sub-splitter; The first sub-splitter is configured to perform interference processing on the received delayed signal and the first modulated signal to obtain a first interference signal; The second sub-splitter is configured to perform interference processing on the received second light field signal and the fourth modulated signal to obtain a second interference signal.

6. The system according to claim 4, characterized in that The optical field signal includes a first optical field signal and a second optical field signal; the optical splitter includes a first sub-splitter and a second sub-splitter; The first sub-splitter is configured to perform interference processing on the received delayed signal and the third modulated signal to obtain a first interference signal; The second sub-splitter is configured to perform interference processing on the received second light field signal and the second modulated signal to obtain a second interference signal.

7. The system according to claim 5 or claim 6, characterized in that The system further includes a first detector and a second detector; the controller includes a first subtractor, a second subtractor, a multiplier, an integrator and a signal processor; The first subtractor is configured to perform differential processing on the first interference signal received by the first detector to obtain a first differential signal; The second subtractor is configured to perform differential processing on the second interference signal received by the second detector to obtain a second differential signal; The multiplier is configured to perform a multiplication operation on the first differential signal and the second differential signal to obtain a first correlation result; The integrator is configured to perform a periodic inner product operation on the first correlation result to obtain a second correlation result; The signal processor is used to perform spectrum analysis on the second correlation result to obtain a coherence measurement result corresponding to the target light field; the coherence measurement result includes an amplitude measurement result and a phase measurement result.

8. An interferometric measurement method, characterized in that: An interferometry system as claimed in any one of claims 1 to 7; the system comprising spatially separated dual receiving apertures, a splitter, a beam splitter, a modulator, and a controller; the method comprising: Determining a plurality of phase sequences having an orthogonal characteristic, sending the plurality of phase sequences to the modulator, so that the modulator performs phase modulation processing on the received reference optical signal according to the plurality of phase sequences to obtain a plurality of modulated signals, and sending the plurality of modulated signals to the optical splitter; receiving a plurality of interference signals sent by the optical splitter; the plurality of interference signals are determined after the optical splitter performs interference processing on the plurality of received light field signals and the plurality of modulated signals; the light field signals are obtained by passing the same target light field through the dual receiving apertures; Coherence analysis is performed on the multiple interference signals to obtain a coherence measurement result corresponding to the target light field.

9. The method according to claim 8, characterized in that The interference signal includes a first interference signal and a second interference signal; and performing coherence analysis on the plurality of interference signals to obtain a coherence measurement result corresponding to the target light field includes: performing differential processing on the first interference signal and the second interference signal respectively to obtain a first differential signal and a second differential signal; A correlation calculation is performed on the first differential signal and the second differential signal to obtain a coherence measurement result corresponding to the target light field.

10. The method according to claim 9, characterized in that The coherence measurement result includes an amplitude measurement result and a phase measurement result; and the correlation calculation of the first differential signal and the second differential signal to obtain the coherence measurement result corresponding to the target light field includes: performing a multiplication operation on the first differential signal and the second differential signal to obtain a first correlation result; performing a periodic inner product operation on the first correlation result to obtain a second correlation result; Performing spectrum analysis on the second correlation result to obtain an amplitude measurement result and a phase measurement result corresponding to the target light field.

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