Temporal lens scanning system, parameter optimization method

Abstract

The application provides a time lens scanning system and a parameter optimization method, and relates to the technical field of ultrafast optics and optoelectronic signal processing. The system comprises a laser emission unit, a time lens unit and a signal processing unit; the laser emission unit is used for emitting continuous laser signals to the time lens unit; the time lens unit is used for applying complex time phase modulation and dispersive propagation to the continuous laser signals to generate a main lobe compressed time domain super-oscillation focusing light pulse signal; and the signal processing unit is used for scanning a to-be-detected target based on the main lobe compressed time domain super-oscillation focusing light pulse signal to obtain a scanning result. The application applies complex time phase modulation and dispersive propagation to the continuous laser signals by the time lens unit to generate a main lobe compressed time domain super-oscillation focusing light pulse signal, so that the time focusing pulse width is further shortened under the condition of limited electronic bandwidth and limited driving capacity, and the time lens resolution is improved.

Description

Technical Field

[0001] This application relates to the field of ultrafast optics and optoelectronic signal processing technology, and more specifically, to a time-lens scanning system and a parameter optimization method. Background Technology

[0002] A time-domain equivalent lens is a lens that applies an approximate second phase over time. ( By using phase curvature and in conjunction with dispersive elements, time-domain focusing and temporal imaging can be achieved. In engineering, flexible, simple, and controllable electro-optic phase modulators are commonly used to generate time-varying phases under radio frequency drive.

[0003] In existing methods, to obtain higher temporal resolution, i.e., a narrower focusing pulse, it is typically necessary to: (1) Larger phase curvature K: requires faster instantaneous frequency sweep or larger modulation voltage; (2) A larger “time aperture”, i.e. a larger effective modulation window; (3) Higher modulation linearity and flatter amplitude and phase response.

[0004] However, in practical systems, the bandwidth and amplitude-phase response of the RF link, power amplifier, and modulator are limited, making it difficult to accurately achieve the ideal second phase over a wide time window. Simply increasing the modulation frequency and voltage is often limited by device cost, losses, drive voltage, and system complexity. Therefore, existing technologies struggle to further shorten the time-focusing pulse width to improve time lens resolution under limited electronic bandwidth and drive capability. Summary of the Invention

[0005] The purpose of this application is to provide a time-lens scanning system and parameter optimization method, which applies composite time-phase modulation and dispersion propagation to a continuous laser signal through a time-lens unit to generate a time-domain super-oscillatory focused light pulse signal with main lobe compression, thereby further shortening the time-focusing pulse width and improving the time-lens resolution under the conditions of limited electronic bandwidth and limited driving capability.

[0006] In a first aspect, embodiments of this application provide a time-lens scanning system, which includes: a laser emitting unit, a time-lens unit, and a signal processing unit; the laser emitting unit is used to emit a continuous laser signal to the time-lens unit; the time-lens unit is used to apply composite time-phase modulation and dispersion propagation to the continuous laser signal to generate a main-lobe compressed time-domain superoscillatory focused light pulse signal; the signal processing unit is used to scan the target to be detected based on the main-lobe compressed time-domain superoscillatory focused light pulse signal to obtain the scanning result.

[0007] In this embodiment, a composite time-phase modulation and dispersion propagation are applied to a continuous laser signal using a time lens unit to generate a main-lobe compressed time-domain superoscillatory focused light pulse signal. This main-lobe compressed time-domain superoscillatory focused light pulse signal is then used to scan the target to obtain the scanning result. This not only further shortens the time-focusing pulse width and improves the resolution of the time lens under the conditions of limited electronic bandwidth and limited driving capability, but also improves the accuracy of the scanning result, thus laying a solid foundation for subsequent analysis based on the scanning result.

[0008] In some embodiments, the time lens unit includes an electro-optic phase modulation module, a composite radio frequency driving module, and a dispersion focusing module; wherein, the composite radio frequency driving module is used to generate a composite radio frequency driving signal; wherein, the composite radio frequency driving signal includes a low-frequency fundamental component and a high-frequency modulation component; the electro-optic phase modulation module is used to receive a continuous laser signal and the composite radio frequency driving signal, and to perform composite time-domain phase modulation on the continuous laser signal based on the composite radio frequency driving signal to generate a composite phase-modulated optical signal; the dispersion focusing module is used to focus and compress the composite phase-modulated optical signal to generate a time-domain super-oscillatory focused optical pulse signal with main lobe compression.

[0009] In this embodiment, the time lens unit includes an electro-optic phase modulation module, a composite radio frequency (RF) drive module, and a dispersive focusing module. The composite RF drive module generates a composite RF drive signal comprising a low-frequency fundamental component and a high-frequency modulation component. In this process, a high-frequency RF component is introduced into the low-frequency RF modulation of a traditional electro-optic time lens, and then combined with the low-frequency RF component to form a composite RF drive signal. This composite RF drive signal acts on the electro-optic phase modulator, causing the continuous laser signal to form a composite time phase in the optical field. After the modulated optical field propagates through the subsequent dispersive medium, the time spread function is reshaped, causing the main lobe shoulder to be suppressed by destructive interference, resulting in a narrowed time main lobe. This forms a time-domain superoscillatory focused optical pulse signal with main lobe compression, achieving a narrower pulse compression effect and improving the resolution of the time lens.

[0010] In some embodiments, the composite radio frequency drive module includes a low-frequency signal generator, a high-frequency signal generator, and a power combiner; the low-frequency signal generator and the high-frequency signal generator are respectively connected to the power combiner; wherein, the low-frequency signal generator is used to generate a low-frequency fundamental component; the high-frequency signal generator is used to generate a high-frequency modulation component; and the power combiner is used to generate a composite radio frequency drive signal based on the low-frequency fundamental component and the high-frequency modulation component.

[0011] In this embodiment, a low-frequency fundamental component is generated by a low-frequency signal generator, a high-frequency modulation component is generated by a high-frequency signal generator, and a composite radio frequency drive signal is generated by a power combiner, thereby significantly reducing intermodulation distortion, ensuring signal purity, and enabling independent and flexible power control.

[0012] In some embodiments, the high-frequency signal generator includes a high-frequency radio frequency source, a gating unit, and a phase shifter; the high-frequency radio frequency source is used to generate an initial high-frequency modulation signal; the gating unit is used to perform time-domain window selection on the initial high-frequency modulation signal to generate a gated high-frequency signal; the phase shifter is used to adjust the phase of the gated high-frequency signal so that the phase-adjusted gated high-frequency signal is symmetrical about the peak position of the low-frequency fundamental component, thereby generating a high-frequency modulation component.

[0013] In this embodiment, the high-frequency signal generator includes a high-frequency radio frequency source, a gating unit, and a phase shifter. The gating unit selects a time-domain window for the initial high-frequency modulation signal, limiting the high-frequency output to a narrow time-domain window of the low-frequency waveform. The phase shifter ensures that the phase-adjusted gated high-frequency signal is symmetrical about the peak position of the low-frequency fundamental component, naturally canceling out the even-order harmonic components of the high-frequency pulse envelope. In this process, the synergy of "time-domain gating" and "phase alignment" allows the high-frequency component to be efficiently injected within the optimal operating window of the low-frequency component, thereby improving energy efficiency.

[0014] In some embodiments, the time lens scanning system further includes a parameter optimization unit; the parameter optimization unit is connected to the composite radio frequency drive module; wherein, the parameter optimization unit is used to generate modulation parameters of the high-frequency modulation component through iterative simulation based on the low-frequency fundamental component and a preset optimization objective function, and send the modulation parameters to the composite radio frequency drive module; wherein, the modulation parameters include high-frequency amplitude parameters, high-frequency parameters and gating parameters.

[0015] In this embodiment, the modulation parameters of the high-frequency modulation component are optimized by the parameter optimization unit, so that the main lobe width of the focused output pulse is reduced under the conditions of limited electronic bandwidth and limited driving power, while controlling the side lobe enhancement and energy loss.

[0016] In some embodiments, the composite radio frequency drive signal is as follows: ;in, Represents the low-frequency fundamental component. Indicates high-frequency modulation components, Indicates low-frequency amplitude. Indicates low frequency. Indicates the low-frequency initial phase. Represents the gate function. Indicates high-frequency amplitude. Indicates high frequency. This indicates the initial phase at high frequencies.

[0017] In this embodiment, a high-frequency modulation component is superimposed on a low-frequency fundamental component. This high-frequency modulation component includes gating parameters, high-frequency amplitude, and high-frequency frequency. In this process, by introducing a gated, phase-shifted, and amplitude-adjusted high-frequency radio frequency modulation component, the composite phase includes a low-frequency near-secondary phase used for focusing a conventional time lens, and a local high-frequency phase texture used for rearranging the focus point spread function, thereby generating a composite phase-modulated optical signal.

[0018] In some embodiments, the composite RF drive module further includes an RF amplifier; the input terminal of the RF amplifier is connected to the output terminal of the power combiner, and the output terminal of the RF amplifier is connected to the electro-optic phase modulation module; wherein, the RF amplifier is used to amplify the composite RF drive signal to generate an amplified composite RF drive signal.

[0019] In this embodiment, the composite radio frequency drive signal is amplified by a radio frequency amplifier to achieve the phase modulation curvature requirement for time-domain pulse focusing, while compensating for signal transmission loss and improving the signal-to-noise ratio.

[0020] In some embodiments, the signal processing unit includes a circulator, a collimator, a detector, and a processing module. The circulator includes a first port, a second port, and a third port. The circulator receives a main lobe-compressed time-domain superoscillatory focused light pulse signal through the first port and transmits the main lobe-compressed time-domain superoscillatory focused light pulse signal to the collimator through the second port. The collimator scans the target to be detected based on the main lobe-compressed time-domain superoscillatory focused light pulse signal to obtain an echo signal. The detector is used to detect the echo signal output through the third port of the circulator and convert the echo signal into an echo electrical signal. The processing module is used to process the echo electrical signal to determine the distance information of the target to be detected.

[0021] In this embodiment, high-resolution detection is achieved by using a time-domain super-oscillatory focused light pulse signal with main lobe compression, while the ranging accuracy is improved by leveraging the common optical path design of the circulator and the narrow pulse time-domain characteristics.

[0022] In some embodiments, the laser emitting unit includes a laser emitting module and a polarization control module, wherein the polarization control module is used to adjust the polarization state of the continuous laser signal emitted by the laser emitting module.

[0023] In this embodiment, the polarization state of the continuous laser signal is adjusted by the polarization control module, so that the continuous laser signal can be highly responsive by the electro-optic phase modulation module, thereby providing the time lens unit with a single-frequency polarization-maintaining continuous optical carrier with low phase noise and high frequency stability, which is the optical basis of time lens modulation.

[0024] Secondly, embodiments of this application provide a parameter optimization method, which includes: generating a fundamental time-lens phase based on low-frequency fundamental component parameters; setting a set of parameters to be optimized for high-frequency modulation components; wherein the set of parameters to be optimized includes initial amplitude parameters, initial frequency parameters, and initial gating parameters; superimposing the initial amplitude parameters and initial frequency parameters, which are limited by the initial gating parameters, onto the fundamental time-lens phase to generate a composite time-domain phase; applying the composite time-domain phase to an input continuous laser signal, combining it with the dispersion propagation equation to generate a time-domain superoscillatory focused optical pulse signal, and constructing a cost function based on the output waveform of the time-domain superoscillatory focused optical pulse signal; iteratively optimizing the set of parameters to be optimized according to the cost function until the optimization stopping condition is met, thereby generating an optimized parameter set.

[0025] In this embodiment, the parameter set to be optimized for the high-frequency modulation component is iteratively optimized using a cost function to obtain a parameter set that meets the requirements. This reduces the main lobe width of the focused output pulse under the conditions of limited electronic bandwidth and limited driving power, while controlling the side lobe enhancement and energy loss.

[0026] Other features and advantages of this application will be set forth in the following description and will be apparent in part from the description or may be learned by practicing embodiments of this application. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the structure of a time-lens scanning system provided in an embodiment of this application; Figure 2 A structural block diagram of a first time-lens scanning system provided in an embodiment of this application; Figure 3 This is a schematic diagram of the structure of a composite radio frequency driving module provided in an embodiment of this application; Figure 4 A flowchart illustrating a parameter optimization method provided in an embodiment of this application; Figure 5 A numerical simulation comparison diagram of a time-focused output pulse provided for an embodiment of this application; Figure 6 A structural block diagram of a second time-lens scanning system provided in an embodiment of this application; Figure 7A full width at half maximum (FWHM) comparison image of a focused pulse provided for embodiments of this application; Figure 8 A comparison chart of the standard deviation of ranging provided for an embodiment of this application.

[0029] Icons: 10-Time lens scanning system, 11-Laser emitting unit, 12-Time lens unit, 13-Signal processing unit, 14-Parameter optimization unit, 111-Laser emitting module, 112-Polarization control module, 121-Electro-optic phase modulation module, 122-Composite RF drive module, 123-Dispersion focusing module, 131-Circulator, 132-Collider, 133-Detector, 134-Processing module, 1221-Low frequency signal generator, 1222-High frequency signal generator, 1223-Power combiner, 1224-RF amplifier, A1-High frequency RF source, A2-Gating unit, A3-Phase shifter. Detailed Implementation

[0030] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0031] It should be noted that all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0032] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0033] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0034] Ordinary electro-optic time lenses typically use only a low-frequency sinusoidal radio frequency signal to drive the electro-optic phase modulator. This sinusoidal signal can be approximated as a quadratic phase near its extreme values, thus achieving a time-focusing effect similar to "lens focusing".

[0035] Specifically, in the mathematical and physical model of a common electro-optic time lens, let the input photoelectric field signal be... The signal modulated by the electro-optic modulator is ,in, The phase shift amount introduced by the sinusoidal radio frequency signal applied to the electro-optic modulator. Indicates time, Indicates modulation depth. This represents the baseband signal angular frequency of the modulated signal.

[0036] At midnight Nearby, Taylor approximates as Therefore, the second phase of the standard time lens is obtained as shown in formula (1), where the time aperture is... No more than 15% of the radio frequency cycle: (1) Based on formula (1), due to the modulation depth The term is a constant and does not affect the focusing effect; the term that acts as a "time lens" is the quadratic phase term. Therefore, the signal modulated by the electro-optic modulator can be expressed as shown in formula (2): (2) As can be seen from the above, a conventional electro-optic time lens actually applies an approximate quadratic phase to the light field along the time axis. This approximate quadratic phase needs to match the time spread provided by subsequent dispersion propagation in order to achieve focusing along the time axis.

[0037] Second-order dispersion propagation in dispersive fibers can be viewed as applying a multiplicative operator to the optical field in the frequency domain. , This represents the dispersion measure. In the time domain, this operator corresponds to a "chirped convolution kernel" (Fresnel kernel): ,in, , Representing the local time variable, we can obtain: (3) When focusing conditions When satisfied, the above formula simplifies to: (4) As can be seen from the above formula, the output time waveform after focusing by the time lens is equal to the time window aperture. Fourier transform, plus one The amplitude scaling. If within the time window... If it is approximately flat, then its Fourier transform is represented by the point spread function of a narrow pulse focused waveform, where the main lobe width of the point spread function (PSF) is... The following quantitative relationship exists with the effective bandwidth: .

[0038] It can be seen that a conventional electro-optic modulation time lens, through sinusoidal driving, approximately generates a secondary time phase near the modulation peak, and its resolution is related to the modulation depth. and modulation angular frequency Related, and effective time aperture It is also limited by the second approximation region and aberrations. Therefore, the system's time-bandwidth product... Typically, it is subject to hard constraints on device bandwidth and maximum phase modulation drive capability.

[0039] Therefore, the temporal aperture and phase curvature of ordinary electro-optic temporal lenses are limited by factors such as radio frequency, modulation depth, and electro-optic modulator bandwidth. This makes it difficult to further shorten the temporal focusing pulse width under limited electronic bandwidth and driving capability, thereby improving the resolution of the temporal lens.

[0040] To address the aforementioned issues, this application proposes a time-lens scanning system and parameter optimization method. This system applies composite time-phase modulation and dispersion propagation to a continuous laser signal through a time-lens unit, generating a time-domain super-oscillatory focused optical pulse signal with main lobe compression. This further shortens the time-focusing pulse width and improves the time-lens resolution under conditions of limited electronic bandwidth and limited driving capability.

[0041] Figure 1 This is a schematic diagram of the structure of a time-lens scanning system provided in an embodiment of this application, as shown below. Figure 1 As shown, the system 10 includes: a laser emitting unit 11, a time lens unit 12, and a signal processing unit 13; the laser emitting unit 11 is used to emit a continuous laser signal to the time lens unit 12; the time lens unit 12 is used to apply composite time phase modulation and dispersion propagation to the continuous laser signal to generate a main lobe-compressed time-domain superoscillatory focused light pulse signal; the signal processing unit 13 is used to scan the target to be detected based on the main lobe-compressed time-domain superoscillatory focused light pulse signal to obtain the scanning result.

[0042] In the above implementation process, the laser emitting unit 11 provides a carrier wave with pure phase characteristics and infinite continuity in time, so that the time lens unit 12 can apply composite time phase modulation to it.

[0043] As an example, the laser emitting unit 11 can use a narrow linewidth continuous laser in conjunction with an external pulse modulator to form a continuous laser signal, or it can directly use a mode-locked pulse laser source to generate a continuous laser signal.

[0044] Laser emitting unit 11 is used to provide the initial light field entering time lens unit 12. .

[0045] The time lens unit 12 is used to apply composite time phase modulation and dispersion propagation to the continuous laser signal to generate a time-domain super-oscillatory focused light pulse signal with main lobe compression.

[0046] Among them, the main lobe-compressed time-domain superoscillatory focused optical pulse signal refers to a special optical pulse signal that applies a specific nonlinear phase modulation to a continuous laser signal through an electro-optic modulator, so that it generates an amplitude zero-crossing change in the time domain faster than the limit determined by the inherent response bandwidth of the system. After passing through a dispersive device, it finally forms a focused spot on the spatial focal plane with a main lobe width (full width at half maximum, FWHM) that is significantly smaller than the traditional diffraction limit (or Fourier transform limit), while suppressing the side lobe energy.

[0047] The principle by which the time lens unit 12 can generate a time-domain super-oscillatory focused light pulse signal with main lobe compression is as follows: To improve the resolution of local details by the time lens unit 12 under given hardware conditions, this application introduces the concept of super-oscillation in spatial super-diffraction imaging: while maintaining the overall bandwidth constraint, a programmable local high-frequency phase texture is applied to the aperture function. The interference structure of the point spread function (PSF) on the focusing plane is rearranged so that its first null point moves towards the center, thereby obtaining a narrower central main lobe (smaller effective main lobe width). Therefore, the time lens unit of this application can also be called a super-oscillating time lens.

[0048] In one embodiment, the time lens unit 12 based on the concept of super-oscillation further superimposes a programmable local high-frequency phase texture on the phase of a conventional electro-optic time lens. Furthermore, focusing on conditions Under these conditions, the output field is a complex aperture function. The Fourier transform of is shown in Equation (5) below. Wherein, local high-frequency phase texture is introduced. This is equivalent to applying a controllable phase mask at the center of the aperture.

[0049] (5) It should be noted that in space super-diffraction imaging, local high-frequency phase texture... Typically, it is 0- optimized with a non-uniform time interval. -0- While distributed high-frequency square modulation signals are possible, in practical applications, arbitrary waveform generators with extremely large electrical bandwidth are typically required to generate such high-frequency square modulation signals.

[0050] Therefore, the embodiments of this application simplify it to gating generated using a mature commercial analog RF source. High-frequency sine wave signal Superimposed on the low-frequency modulation signal of a regular time lens This rearranges the zeros of the Fourier surface spread function (PSF), thus reducing the main lobe width. (6) Based on Jacobi–Anger, there is... (7) After simplifying formula (6) according to formula (7), the rearranged Fourier surface can be expressed as shown in formula (8): (8) As can be seen from the above formula (8), the output is no longer a single sinc main lobe, but a coherent superposition of a series of shifted sinc-type components. When the parameters of the high-frequency modulation signal... and When designed properly, the shift component will destructively interfere with the original main lobe in the "shoulder region" of the normal main lobe, generating a correction term that shifts the pulse half-maximum towards the center. This reduces shoulder strength, causing the half-width at half-maximum (HWHM) position to shift towards the center, ultimately resulting in a point spread function (PSF) main lobe width. It gets smaller.

[0051] Therefore, the time lens unit 12 in this embodiment aims to construct a time-domain modulation waveform with local super-oscillation characteristics by superimposing a higher carrier frequency radio frequency component, based on the low-frequency modulation of the "approximately second phase" of a conventional electro-optic time lens, without significantly increasing the maximum bandwidth of the radio frequency link and the system complexity. This waveform generates a higher equivalent phase curvature and a faster instantaneous frequency change near the focal point, thereby compressing the focusing pulse width and enabling the time lens to form a narrower main lobe focusing pulse near the focal point, while maintaining feasibility and repeatability.

[0052] It should be noted that the high-frequency phase texture is not limited to a single sine wave, but can be a multi-tone superposition, a piecewise sine wave, a phase-jump sine wave, an approximate square wave, a chirped sine wave, or any periodic waveform after pre-distortion compensation. The gating function g(t) can be a rectangular window, a super-Gaussian window, a Gaussian window, a raised-cosine window, or a combination thereof.

[0053] It should also be noted that high-frequency phase textures can be directly superimposed on the phase modulation link, or equivalent aperture encoding can be achieved through nonlinear optical effects such as I / Q modulation, dual parallel Mach-Zehnder modulators, or four-wave mixing to obtain an approximate point spread function (PSF) rearrangement effect.

[0054] The signal processing unit 13 is used to scan the target to be detected by the time-domain super-oscillatory focused light pulse signal based on main lobe compression, and obtain the scanning results to measure key indicators such as the time waveform of the pulse output by the time lens unit 12 and the full width at half maximum (FWHM) of the main lobe.

[0055] The scanning results can be used to determine the distance information of the target to be detected.

[0056] In this embodiment, a composite time-phase modulation and dispersion propagation are applied to a continuous laser signal using a time lens unit to generate a main-lobe compressed time-domain superoscillatory focused light pulse signal. This main-lobe compressed time-domain superoscillatory focused light pulse signal is then used to scan the target to obtain the scanning result. This not only further shortens the time-focusing pulse width and improves the resolution of the time lens under limited electronic bandwidth and limited driving capability, but also improves the accuracy of the ranging result, thus laying a solid foundation for subsequent analysis based on the scanning ranging result.

[0057] Figure 2 A structural block diagram of the first time-lens scanning system provided in the embodiments of this application is shown below. Figure 2 As shown, in some embodiments, the time lens unit 12 includes an electro-optic phase modulation module 121, a composite radio frequency drive module 122, and a dispersion focusing module 123; wherein, the composite radio frequency drive module 122 is used to generate a composite radio frequency drive signal; wherein, the composite radio frequency drive signal includes a low-frequency fundamental component and a high-frequency modulation component; the electro-optic phase modulation module 121 is used to receive a continuous laser signal and a composite radio frequency drive signal, and to perform composite time-domain phase modulation on the continuous laser signal based on the composite radio frequency drive signal to generate a composite phase-modulated optical signal; the dispersion focusing module 123 is used to focus and compress the composite phase-modulated optical signal to generate a time-domain super-oscillatory focused optical pulse signal with main lobe compression.

[0058] In the above implementation process, the electro-optic phase modulation module 121 includes an electro-optic phase modulator or other equivalent high-speed phase modulation device.

[0059] The function of this module is to apply the composite radio frequency driving signal generated by the composite radio frequency driving module 122 to the optical phase information of the continuous laser signal, so that the continuous laser signal obtains the composite time phase generated by the composite radio frequency driving module 122, thereby forming a controllable super-oscillatory phase texture at the center of the time aperture and generating a composite phase modulated optical field signal. This provides conditions for the rearrangement of the point spread function (PSF) in the dispersion propagation of the subsequent dispersion focusing module 123.

[0060] The composite RF drive module 122 is used to generate a composite time-domain modulation signal to drive the electro-optic phase modulator. The composite RF drive signal includes a low-frequency fundamental component and a high-frequency modulation component.

[0061] In practice, the low-frequency fundamental component and the high-frequency modulation component can be generated by multiple independent RF sources combined and then driving the same modulator, or they can be generated by a single AWG, DDS, phase-locked source or FPGA / DAC and then amplified and driven; or the low-frequency and high-frequency phases can be loaded separately by two series or parallel modulators.

[0062] The dispersion focusing module 123 includes a dispersive fiber, a chirped fiber grating, a waveguide dispersive device, or other optical devices that can provide equivalent second-order dispersion.

[0063] Dispersion focusing module 123 is used for focusing the optical field signal after composite phase modulation. The post-stage dispersion is provided to satisfy the focusing relationship of the time lens, so that the composite modulated light field forms a compressed output pulse at the time domain focal point, and the compressed output pulse is output to the signal processing unit 13 for measurement.

[0064] Compared with ordinary electro-optic time lenses, the embodiments of this application rearrange the time spread function PSF of the focal plane through super oscillatory phase texture, thereby further reducing the main lobe width and thus obtaining higher time resolution or shorter focusing pulse.

[0065] In this embodiment, the time lens unit includes an electro-optic phase modulation module, a composite radio frequency (RF) drive module, and a dispersive focusing module. The composite RF drive module generates a composite RF drive signal comprising a low-frequency fundamental component and a high-frequency modulation component. In this process, a high-frequency RF component is introduced into the low-frequency RF modulation of a traditional electro-optic time lens, and then combined with the low-frequency RF component to form a composite RF drive signal. This composite RF drive signal acts on the electro-optic phase modulator, causing the continuous laser signal to form a composite time phase in the optical field. After the modulated optical field propagates through the subsequent dispersive medium, the time spread function is reshaped, causing the main lobe shoulder to be suppressed by destructive interference, resulting in a narrowed time main lobe. This forms a time-domain superoscillatory focused optical pulse signal with main lobe compression, achieving a narrower pulse compression effect and improving the resolution of the time lens.

[0066] Figure 3 This is a schematic diagram of the structure of a composite radio frequency driving module provided in an embodiment of this application, as shown below. Figure 3As shown, in some embodiments, the composite radio frequency drive module 122 includes a low-frequency signal generator 1221, a high-frequency signal generator 1222, and a power combiner 1223; the low-frequency signal generator 1221 and the high-frequency signal generator 1222 are respectively connected to the power combiner 1223; wherein, the low-frequency signal generator 1221 is used to generate a low-frequency fundamental component; the high-frequency signal generator 1222 is used to generate a high-frequency modulation component; and the power combiner 1223 is used to generate a composite radio frequency drive signal based on the low-frequency fundamental component and the high-frequency modulation component.

[0067] In the above implementation process, the clocks of the low-frequency signal generator 1221 and the high-frequency signal generator 1222 are synchronized.

[0068] The low-frequency signal generator 1221 is a low-frequency radio frequency source used to generate low-frequency fundamental components.

[0069] See also Figure 3 The high-frequency signal generator 1222 includes a high-frequency radio frequency source A1, a gating unit A2, and a phase shifter A3. The high-frequency radio frequency source A1 is used to generate an initial high-frequency modulation signal. The gating unit A2 is used to select a time-domain window for the initial high-frequency modulation signal to generate a gated high-frequency signal. The phase shifter A3 is used to adjust the phase of the gated high-frequency signal so that the phase-adjusted gated high-frequency signal is symmetrical about the peak position of the low-frequency fundamental component, thereby generating a high-frequency modulation component.

[0070] In this process, the gating unit selects a time-domain window for the initial high-frequency modulation signal, limiting the high-frequency output to a narrow time-domain window of the low-frequency waveform. A phase shifter ensures that the phase-adjusted gated high-frequency signal is symmetrical about the peak position of the low-frequency fundamental component, naturally canceling out the even-order harmonic components of the high-frequency pulse envelope. Therefore, through the synergy of "time-domain gating" and "phase alignment," high-frequency components are efficiently injected within the optimal operating window of the low-frequency components, thereby improving energy efficiency.

[0071] Furthermore, a low-frequency fundamental component is generated by a low-frequency signal generator, a high-frequency modulation component is generated by a high-frequency signal generator, and then a composite radio frequency drive signal is generated by a power combiner, thereby significantly reducing intermodulation distortion, ensuring signal purity, and enabling independent and flexible power control.

[0072] See also Figure 3 In some embodiments, the composite RF drive module 122 further includes an RF amplifier 1224; the input terminal of the RF amplifier 1224 is connected to the output terminal of the power combiner 1223, and the output terminal of the RF amplifier 1224 is connected to the electro-optic phase modulation module 121; wherein, the RF amplifier 1224 is used to amplify the composite RF drive signal to generate an amplified composite RF drive signal.

[0073] In the above implementation process, the output of the RF amplifier 1224 is connected to the RF input of the electro-optic phase modulation module 121 via an optical fiber link. The RF amplifier amplifies the composite RF drive signal to achieve the phase modulation curvature required for time-domain pulse focusing, while compensating for signal transmission loss and improving the signal-to-noise ratio.

[0074] according to Figure 3 As shown in the schematic diagram of the composite RF drive module, the output terminal of the low-frequency RF source 1221 is connected to the first input terminal of the power combiner 1223; the output terminal of the high-frequency RF source A1 is connected to the input terminal of the gate unit A2; the output terminal of the gate unit A2 is connected to the phase shifter A3; the output terminal of the phase shifter A3 is connected to the second input terminal of the power combiner 1223; the output terminal of the power combiner 1223 is connected to the input terminal of the RF amplifier 1224; and the output terminal of the RF amplifier 1224 is connected to the RF input terminal of the electro-optic phase modulation module 121.

[0075] The signal relationship is as follows: the low-frequency radio frequency source provides the approximate second-order phase drive component required by a conventional electro-optic time lens. The high-frequency radio frequency source provides additional high-frequency modulation components. The gating unit is used to select the time-domain window for the high-frequency modulation components, ensuring that they are superimposed only near the effective aperture of the lens. The high-frequency gating signal is obtained. Two or more radio frequency signals are combined by a power amplifier and then amplified by a driver amplifier before being jointly applied to an electro-optic phase modulator.

[0076] The combined RF signal is amplified by an RF amplifier to form a super-oscillating composite drive waveform. The signal is then applied to the radio frequency input of the electro-optic phase modulator, thereby converting the electrical intensity signal into optical phase information.

[0077] The optical field modulated by the composite RF driving module 122 and the electro-optic phase modulation module 121 can be expressed as follows: ,in, This is the approximate second phase required for a typical electro-optic time lens. To provide local high-frequency phase texture within the effective time aperture, wherein, The electro-optic phase modulation module 121 modulates the voltage based on its half-wave voltage. The generated modulation depth. Light field. Enter the dispersive focusing module 123.

[0078] As can be seen from the above, in some embodiments, the composite radio frequency drive signal is as follows: ;in, Represents the low-frequency fundamental component. Indicates high-frequency modulation components, Indicates low-frequency amplitude. Indicates low frequency. Indicates the low-frequency initial phase. Represents the gate function. Indicates high-frequency amplitude. Indicates high frequency. This indicates the initial phase at high frequencies.

[0079] Among them, the gate function High frequency amplitude and high frequency It can be generated by parameter optimization unit 14.

[0080] By introducing high-frequency radio frequency modulation components that are gated, phase-shifted, and amplitude-adjusted, the composite phase includes a low-frequency near-secondary phase used to achieve focusing by a conventional time lens, as well as a local high-frequency phase texture used to rearrange the focus point spread function, thereby generating a composite phase modulated optical signal.

[0081] See also Figure 2 In some embodiments, the time lens scanning system 10 further includes a parameter optimization unit 14; the parameter optimization unit 14 is connected to the composite radio frequency drive module 122; wherein, the parameter optimization unit 14 is used to generate modulation parameters of the high-frequency modulation component through iterative simulation based on the low-frequency fundamental component and the preset optimization objective function, and send the modulation parameters to the composite radio frequency drive module 122; wherein, the modulation parameters include high-frequency amplitude parameters, high-frequency parameters and gating parameters.

[0082] In the above implementation process, the parameter optimization unit 14 can optimize the amplitude of the high-frequency modulation component in the composite RF drive module 122. ,frequency Gating The width is optimized through numerical simulation to achieve a trade-off between "main lobe compression, side lobe suppression, and energy efficiency." The specific optimization process of parameter optimization unit 14 will be described in subsequent embodiments and will not be repeated here.

[0083] In this embodiment, the modulation parameters of the high-frequency modulation component are optimized by the parameter optimization unit, so that the main lobe width of the focused output pulse is reduced under the conditions of limited electronic bandwidth and limited driving power, while controlling the side lobe enhancement and energy loss.

[0084] In some embodiments, the signal processing unit 13 includes: a circulator 131, a collimator 132, a detector 133, and a processing module 134; the circulator 131 includes a first port 1, a second port 2, and a third port 3; the circulator 131 receives a main lobe-compressed time-domain superoscillatory focused light pulse signal through the first port 1, and transmits the main lobe-compressed time-domain superoscillatory focused light pulse signal to the collimator 132 through the second port 2; the collimator 132 scans the target to be detected based on the main lobe-compressed time-domain superoscillatory focused light pulse signal to obtain an echo signal; the detector 133 is used to detect the echo signal output through the third port 3 of the circulator 131, and converts the echo signal into an echo electrical signal; the processing module 134 is used to process the echo electrical signal to determine the distance information of the target to be detected.

[0085] In this embodiment, high-resolution detection is achieved by using a time-domain super-oscillatory focused light pulse signal with main lobe compression, while the ranging accuracy is improved by leveraging the common optical path design of the circulator and the narrow pulse time-domain characteristics.

[0086] See also Figure 2 In some embodiments, the laser emitting unit 11 includes a laser emitting module 111 and a polarization control module 112, wherein the polarization control module 112 is used to adjust the polarization state of the continuous laser signal emitted by the laser emitting module 111.

[0087] In the above implementation process, the laser emitting module 111 can use a narrow linewidth continuous laser in conjunction with an external pulse modulator to form a continuous laser signal, or it can directly use a mode-locked pulse laser source to generate a continuous laser signal.

[0088] The polarization control module 112 includes one or more polarization controllers, and may also include polarization-maintaining optical fibers or other polarization management devices if necessary.

[0089] Before the input optical pulse enters the electro-optic phase modulation module 121, the polarization state must be adjusted by the polarization control module 112 to match the working polarization axis of the electro-optic phase modulator in the subsequent electro-optic phase modulation module 121, thereby ensuring that the modulator works in a linear, stable and highly efficient phase modulation state.

[0090] The polarization control module 112 can reduce modulation depth fluctuations, insertion loss variations, and system output instability caused by polarization drift, thereby improving the repeatability and robustness of the time lens unit 12.

[0091] In this embodiment, the polarization state of the continuous laser signal is adjusted by the polarization control module, so that the continuous laser signal can be highly responsive by the electro-optic phase modulation module, thereby providing the time lens unit with a single-frequency polarization-maintaining continuous optical carrier with low phase noise and high frequency stability, which is the optical basis of time lens modulation.

[0092] Figure 4 This is a flowchart illustrating a parameter optimization method provided in an embodiment of this application. The method is applied to a parameter optimization unit. Figure 4 As shown, the method includes: Step S401: Generate the fundamental time lens phase based on the low-frequency fundamental component parameters; Step S402: Set the set of parameters to be optimized for the high-frequency modulation components; wherein, the set of parameters to be optimized includes initial amplitude parameters, initial frequency parameters and initial gating parameters; Step S403: On the basic time lens phase, the initial amplitude parameter and the initial frequency parameter, which are limited by the initial gating parameter, are superimposed to generate a composite time-domain phase; Step S404: Apply the composite time-domain phase to the input continuous laser signal, combine it with the dispersion propagation equation to generate a time-domain super-oscillatory focused optical pulse signal, and construct a cost function based on the output waveform of the time-domain super-oscillatory focused optical pulse signal; Step S405: Based on the cost function, iteratively optimize the parameter set to be optimized until the optimization stopping condition is met, and generate the optimized parameter set.

[0093] In the above implementation process, firstly, the parameter optimization unit reads the system fixed parameters that are not involved in the optimization. These system fixed parameters include the input optical pulse parameters and the total system dispersion. Detector bandwidth And the low-frequency modulation parameters of a conventional electro-optic time lens. The low-frequency modulation parameters are used as low-frequency fundamental component parameters to generate the fundamental time lens phase.

[0094] The input light pulse parameters include the center wavelength of the input light source. Low-frequency modulation parameters include the low-frequency radio frequency drive frequency. and the period of low-frequency radio frequency signals .

[0095] Subsequently, a set of parameters to be optimized for the high-frequency modulation components is defined, including the initial amplitude parameters. Initial frequency parameters and initial gating parameters Among them, the initial gating parameters It can be The set of parameters to be optimized may also include phase parameters that make the waveform symmetrical. .

[0096] A gated high-frequency phase texture is superimposed on the fundamental time-domain lens phase to form a composite time-domain phase. This composite time-domain phase is then applied to the input light pulse, and the output focused pulse waveform is numerically calculated using a dispersion propagation model.

[0097] The parameter optimization unit extracts indicators such as full width at half maximum (FWHM) and main lobe energy ratio from the output waveform and constructs a cost function.

[0098] When the cost function does not meet the optimization stopping condition, the parameter optimization unit updates the high-frequency modulation parameters according to the preset optimization algorithm. , , The process of generating composite phase, simulating dispersion propagation, and extracting output parameters is repeated.

[0099] When the cost function satisfies the optimization stopping condition, the optimal high-frequency modulation parameters are output and used in the composite RF drive module to generate the final super-oscillating composite RF modulation signal.

[0100] The optimization algorithm can be a particle swarm optimization algorithm. The optimization stopping condition can be that the loss function changes very little, the maximum number of iterations is reached, or the output waveform meets the requirements for main lobe compression and stability.

[0101] This optimization process allows for a reduction in the main lobe width of the focused output pulse under conditions of limited electronic bandwidth and limited driving power, while simultaneously controlling sidelobe enhancement and energy loss.

[0102] In one embodiment, the center wavelength of the input light source Total dispersion Low-frequency radio frequency drive frequency The period of low-frequency radio frequency signals Detector bandwidth .

[0103] Based on low-frequency radio frequency drive frequency and the period of low-frequency radio frequency signals A model of a conventional electro-optic time lens is constructed, and the output waveform of the conventional electro-optic time lens is calculated. The full width at half maximum (FWHM) of the conventional electro-optic time lens is extracted from the output waveform and used as a reference benchmark to determine whether the waveform after subsequent superposition of gated high-frequency phase textures achieves main lobe compression.

[0104] An initial gated high-frequency phase texture is superimposed on the fundamental time-domain lens phase to form a composite time-domain phase. This composite time-domain phase is then applied to the input light pulse, and the output focused pulse waveform is numerically calculated using a dispersion propagation model.

[0105] Considering the characteristics of super oscillations, such as the main lobe narrowing, but usually accompanied by problems such as increased side lobes, decreased main lobe energy ratio, and greater sensitivity to modulation parameters.

[0106] Therefore, a multi-constraint loss function is constructed as the cost function to evaluate the parameters in the parameter set to be optimized. For example, the multi-constraint loss function is... ,in, This indicates the main lobe compression term. This indicates the sidelobe constraint term. This represents the main lobe energy constraint term. This indicates a multi-peak constraint term. This represents the high-frequency modulation depth constraint term. This represents the weighting coefficient of each constraint term. In one implementation, .

[0107] This indicates that, during the optimization process, the main lobe compression term is the primary objective; side lobe suppression and main lobe energy preservation are important constraints; and multi-peak constraints and high-frequency modulation depth constraints are used to further ensure peak stability and experimental feasibility.

[0108] The multi-constraint loss function can be understood as a screening rule: only when a set of high-frequency parameters can simultaneously satisfy main lobe compression, side lobe control, energy concentration, single-peak stability and hardware feasibility will the set of parameters be considered as the preferred parameters.

[0109] Figure 5 A numerical simulation comparison chart of a time-focused output pulse provided for an embodiment of this application is provided by... Figure 5 It can be seen that, under a set of optimized high-frequency amplitude parameters, high-frequency frequency parameters and gating parameters, compared with ordinary electro-optic time lens, the full width at half maximum (FWHM) of the focusing pulse can be compressed from 70.20ps to 58.20ps, with a compression ratio of approximately 17.1%.

[0110] In this embodiment, the parameter set to be optimized for the high-frequency modulation component is iteratively optimized using a cost function to obtain a parameter set that meets the requirements. This reduces the main lobe width of the focused output pulse under the conditions of limited electronic bandwidth and limited driving power, while controlling the side lobe enhancement and energy loss.

[0111] Figure 6 The structural block diagram of the second time-lens scanning system provided in this application embodiment is used to verify the effect of the time-lens system based on time-domain superoscillation composite radio frequency modulation in pulse compression and time-of-flight ranging, thereby verifying the feasibility and performance improvement effect of the time-lens scanning system provided in this application in practice.

[0112] The system mainly includes a light pulse generation and polarization control section, a composite radio frequency drive section, an electro-optic phase modulation section, a dispersion focusing section, a free space reflection ranging section, and an output detection and data acquisition section.

[0113] Figure 6When the system is operating, the continuous-wave laser first generates a narrow-linewidth optical signal to be compressed with a wavelength of 1550nm. This compressed optical signal, after its polarization state is adjusted by a polarization controller, enters the electro-optic phase modulator. Simultaneously, the super-oscillating composite RF drive section consists of two RF sources. The low-frequency RF source outputs a low-frequency sinusoidal signal of 1.775GHz and -19dBm, serving as the fundamental driving component for the traditional time lens. The high-frequency RF source outputs a high-frequency... With high frequency modulation intensity High-frequency sinusoidal signals of 17.75 GHz and -22 dBm, respectively, with gate widths... It is 15% of the period of the low-frequency sinusoidal signal, of which the high-frequency modulation intensity High frequency and gate width The parameters are quantitatively obtained from the simulation by the parameter optimization unit, and the phase is adjusted by the phase shifter to serve as the additional modulation component of the super oscillation.

[0114] The two RF signals are combined into a composite RF drive signal by a power divider / combiner, then amplified by a 40dB low-noise amplifier and applied to the phase modulation link to achieve modulation depth of the input optical pulse. The composite time-domain phase modulation is 1. The modulated optical signal enters a dispersive optical fiber with a total dispersion of approximately 2009 ps / nm for time focusing and to form a compressed pulse.

[0115] Subsequently, the compressed optical pulse is input from port 1 of the circulator and output from port 2 to the collimator. The collimator transmits the optical signal to the target in the free space reflection branch. The echo light reflected by the target returns to port 2 of the circulator via the collimator and is output from port 3 of the circulator to the 40 GHz photodetector.

[0116] The photodetector converts the echo light pulse into an electrical signal and obtains the output waveform through real-time measurement and waveform acquisition. Further, it extracts indicators such as pulse full width at half maximum (FWHM), peak position, and standard deviation of repeated ranging to evaluate the pulse compression effect and ranging stability of the super-oscillating composite radio frequency modulation time lens system.

[0117] First, we will analyze it from the perspective of the full width at half maximum (FWHM) of the focused pulse. Figure 7 A full width at half maximum (FWHM) comparison image of a focused pulse is provided for embodiments of this application, such as... Figure 7As shown, the full width at half maximum (FWHM) of the output pulse from a conventional electro-optic time lens (NTL) is 55.58 ps; after employing the super-oscillating time lens (SOTL) of this application, the FWHM of the original sampling result is 29.92 ps. Compared to the conventional electro-optic time lens, the FWHM of the focusing pulse from the SOTL is reduced by approximately 46.17%. This result demonstrates that by superimposing a phase-shift controlled high-frequency modulation component onto a conventional low-frequency time lens drive, this application can significantly compress the output main lobe width without significantly increasing the system's maximum electronic bandwidth, thereby enhancing temporal focusing capability.

[0118] Secondly, an analysis is conducted from the perspective of the statistical dispersion of the flight time ranging results. Figure 8 A distance measurement standard deviation comparison chart is provided for embodiments of this application, such as... Figure 8 As shown, multiple sets of repeated ranging experiments were conducted using both a conventional electro-optic time lens and the super-oscillating time lens of this application, with the standard deviation of the repeated measurements used as the evaluation index for ranging stability. Experimental results show that the standard deviations of the ranging measurements using the conventional electro-optic time lens in the six sets of experiments were 0.0332 cm, 0.0327 cm, 0.0289 cm, 0.0305 cm, 0.0307 cm, and 0.0328 cm, respectively, with an average standard deviation of approximately 0.0315 cm. The standard deviations of the ranging measurements using the super-oscillating time lens of this application in the corresponding five sets of experiments were 0.0119 cm, 0.0122 cm, 0.0121 cm, 0.0122 cm, 0.0124 cm, and 0.0125 cm, respectively, with an average standard deviation of approximately 0.0122 cm. Compared to the conventional electro-optic time lens, the proposed solution reduces the average standard deviation of the ranging measurement by 61.3%.

[0119] The experimental results above demonstrate that the super-oscillating time lens proposed in this application can not only achieve narrower main lobe compression by rearranging the time focal point diffusion function, but also improve the consistency of peak positioning and reduce time jitter and distance estimation dispersion in repeated measurements, thereby simultaneously obtaining better time resolution and higher ranging stability. Therefore, it has clear engineering application value and is suitable for application scenarios such as pulse compression, time focusing, ultrafast sampling, high-precision time delay measurement and laser ranging.

[0120] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Additionally, the displayed or discussed mutual couplings, direct couplings, or communication connections may be through some communication interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.

[0121] Furthermore, the units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0122] Furthermore, the functional modules in the various embodiments of this application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0123] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A time-lens scanning system, characterized in that, The system includes: a laser emitting unit, a time lens unit, and a signal processing unit; The laser emitting unit is used to emit continuous laser signals to the time lens unit; The time lens unit is used to apply composite time phase modulation and dispersion propagation to the continuous laser signal to generate a time-domain superoscillatory focused light pulse signal with main lobe compression. The signal processing unit is used to scan the target to be detected based on the time-domain super-oscillatory focused light pulse signal compressed by the main lobe, and obtain the scanning result.

2. The time-lens scanning system according to claim 1, characterized in that, The time lens unit includes an electro-optic phase modulation module, a composite radio frequency driving module, and a dispersive focusing module; The composite radio frequency driving module is used to generate a composite radio frequency driving signal; wherein the composite radio frequency driving signal includes a low-frequency fundamental component and a high-frequency modulation component. The electro-optic phase modulation module is used to receive the continuous laser signal and the composite radio frequency drive signal, and to perform composite time-domain phase modulation on the continuous laser signal based on the composite radio frequency drive signal to generate a composite phase-modulated optical signal. The dispersive focusing module is used to focus and compress the composite phase-modulated optical signal to generate the main lobe-compressed time-domain superoscillatory focused optical pulse signal.

3. The time-lens scanning system according to claim 2, characterized in that, The composite radio frequency drive module includes a low-frequency signal generator, a high-frequency signal generator, and a power combiner. The low-frequency signal generator and the high-frequency signal generator are respectively connected to the power combiner. The low-frequency signal generator is used to generate the low-frequency fundamental component. The high-frequency signal generator is used to generate the high-frequency modulation component; The power combiner is used to generate the composite radio frequency drive signal based on the low-frequency fundamental component and the high-frequency modulation component.

4. The time-lens scanning system according to claim 3, characterized in that, The high-frequency signal generator includes a high-frequency radio frequency source, a gating unit, and a phase shifter; The high-frequency radio frequency source is used to generate an initial high-frequency modulation signal; The gating unit is used to perform time-domain window selection on the initial high-frequency modulation signal to generate a gated high-frequency signal; The phase shifter is used to adjust the phase of the gated high-frequency signal so that the phase-adjusted gated high-frequency signal is symmetrical about the peak position of the low-frequency fundamental component, thereby generating the high-frequency modulation component.

5. The time-lens scanning system according to claim 4, characterized in that, The time-lens scanning system further includes a parameter optimization unit; the parameter optimization unit is connected to the composite radio frequency drive module. The parameter optimization unit is used to generate modulation parameters of the high-frequency modulation component through iterative simulation based on the low-frequency fundamental component and a preset optimization objective function, and send the modulation parameters to the composite radio frequency drive module; wherein the modulation parameters include high-frequency amplitude parameters, high-frequency frequency parameters and gating parameters.

6. The time-lens scanning system according to claim 4, characterized in that, The composite radio frequency drive signal is as follows: in, This represents the low-frequency fundamental component. This refers to the high-frequency modulation component. Indicates low-frequency amplitude. Indicates low frequency. Indicates the low-frequency initial phase. Represents the gate function. Indicates high-frequency amplitude. Indicates high frequency. This indicates the initial phase at high frequencies.

7. The time-lens scanning system according to claim 3, characterized in that, The composite RF drive module further includes an RF amplifier; the input terminal of the RF amplifier is connected to the output terminal of the power combiner, and the output terminal of the RF amplifier is connected to the electro-optic phase modulation module. The radio frequency amplifier is used to amplify the composite radio frequency drive signal to generate an amplified composite radio frequency drive signal.

8. The time-lens scanning system according to claim 1, characterized in that, The signal processing unit includes: a circulator, a collimator, a detector, and a processing module; The circulator includes a first port, a second port, and a third port; The circulator receives the main lobe-compressed time-domain super-oscillatory focused light pulse signal through the first port, and transmits the main lobe-compressed time-domain super-oscillatory focused light pulse signal to the collimator through the second port; The collimator scans the target to be detected based on the time-domain superoscillatory focused light pulse signal compressed by the main lobe to obtain the echo signal; The detector is used to detect the echo signal output through the third port of the circulator and convert the echo signal into an echo electrical signal; The processing module is used to process the echo electrical signal to determine the distance information of the target to be detected.

9. The time-lens scanning system according to any one of claims 1-8, characterized in that, The laser emitting unit includes a laser emitting module and a polarization control module. The polarization control module is used to adjust the polarization state of the continuous laser signal emitted by the laser emitting module.

10. A parameter optimization method, characterized in that, The method includes: Generate the fundamental time lens phase based on the low-frequency fundamental component parameters; A set of parameters to be optimized for the high-frequency modulation components is defined; wherein the set of parameters to be optimized includes initial amplitude parameters, initial frequency parameters, and initial gating parameters; On the basic time lens phase, the initial amplitude parameter and the initial frequency parameter, which are limited by the initial gating parameter, are superimposed to generate a composite time-domain phase; The composite time-domain phase is applied to the input continuous laser signal, and a time-domain super-oscillatory focused optical pulse signal is generated by combining the dispersion propagation equation. A cost function is constructed based on the output waveform of the time-domain super-oscillatory focused optical pulse signal. Based on the cost function, the set of parameters to be optimized is iteratively optimized until the optimization stopping condition is met, and the optimized set of parameters is generated.

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