Three-dimensional optical scanning holographic system based on electric focusing adaptive optical device

Abstract

The invention relates to the technical field of optical imaging and detection, in particular to a three-dimensional optical scanning holographic system based on an electric focusing adaptive optical device. Comprising the following optical and electrical components: a laser, a beam splitter, an acousto-optic modulator, a first plane mirror, an electric focusing liquid lens, a first Fourier lens, a second plane mirror, a second pupil, a second Fourier lens, a second beam splitter, an XY scanning galvanometer and a sample. The system comprises a condenser lens, a photoelectric detector, a band-pass filter, a first lock-in amplifier, a second lock-in amplifier and a host. The host is respectively connected with each electric device and is used for synchronous control and image reconstruction; the electric focusing liquid lens is arranged on the front focal plane of the first Fourier lens and used for modulating the curvature of a light beam in real time according to the driving voltage output by the host and achieving continuous or stepping control over the axial focus position, and the system does not need mechanical movement, is high in response speed, has the flexible layer selection capacity and can be seamlessly synchronized with transverse scanning.

Description

Technical Field

[0001] This invention relates to the field of optical imaging and detection technology, specifically to a three-dimensional optical scanning holographic system based on an electrically adjustable adaptive optics device, used to achieve rapid three-dimensional imaging and dynamic wavefront aberration correction. Background Technology

[0002] Optical Scanning Holography (OSH) is a digital holographic technique based on the principle of dual-pupil heterodyne interferometry scanning imaging. Unlike traditional digital holography based on coherent illumination, OSH uses the interference of two light waves of different frequencies (typically a plane wave and a spherical wave) to form a time-dependent Fresnel zone plate (TD-FZP) spot, which is then used to perform a two-dimensional grating scan of the object. The light signal transmitted through the object is collected by a single-pixel detector, and the holographic data is extracted using lock-in amplification or heterodyne demodulation techniques. Due to its unique incoherent holographic imaging capabilities, OSH has significant application value in fields such as biomedical fluorescence microscopy, remote sensing, and 3D object recognition.

[0003] However, existing OSH (Optical Shutter Hierarchy) systems have significant limitations when performing 3D tomography or acquiring high signal-to-noise ratio cross-sectional images through physical focusing. Although OSH has holographic recording capabilities and can reconstruct images of different depths in a computer using digital refocusing algorithms, in practical applications, to obtain optimal optical resolution at a specific depth or to perform large-scale physical tomography on thick samples, it is often necessary to change the relative position between the focal plane of the scanning spot and the object. The current conventional approach is to use a mechanical scanning scheme, that is, keeping the optical system stationary and driving the stage along the axial direction (Z-axis) through a precise mechanical displacement stage (such as a stepper motor or piezoelectric ceramic displacement stage); or keeping the object stationary and moving the entire bulky optical scanning head.

[0004] This axial scanning method based on mechanical motion has the following significant drawbacks: 1. Limited scanning speed makes it difficult to capture dynamic processes. Axial scanning relies on the physical movement of the stage or bulky optical scanning head. The inherent physical inertia of the mechanical components means that their movement and stable settling take a long time. This mechanical limitation keeps the scanning speed typically in the second range, making it difficult to achieve high-speed tomography at the millisecond level, and failing to meet the needs of real-time three-dimensional observation of rapidly changing biodynamic processes such as cell movement and neural activity.

[0005] 2. Mechanical vibration significantly reduces the signal-to-noise ratio (SNR) of the image. Optical scanning holographic systems are essentially dual-pupil heterodyne interferometric imaging devices, which are extremely sensitive to environmental vibrations. The mechanical displacement stage inevitably introduces mechanical jitter during the driving process. This slight jitter can cause the phase of the interference fringes to drift or become blurred, thus significantly increasing background noise and severely reducing the quality and signal-to-noise ratio (SNR) of the reconstructed hologram.

[0006] 3. Rigid scanning patterns and low data acquisition efficiency: Mechanical scanning must follow a sequential scanning physical path, making instantaneous jumps between different depths impossible. For samples with sparse or layered axial distribution (such as multilayer microfluidic chips), the mechanical system has to spend a significant amount of time scanning invalid regions between layers. Furthermore, hysteresis errors in the mechanical transmission also affect repeatability, resulting in low data acquisition efficiency and high redundancy. While existing optical scanning holography (OSH) technology possesses unique advantages in incoherent holographic imaging, it has long been constrained by mechanical scanning methods in three-dimensional tomographic imaging. Traditional mechanical stage or scanning head displacement schemes have inherent physical inertia, resulting in slow axial scanning speed, significant system vibration, and easy introduction of phase noise, making it difficult to meet the requirements of real-time three-dimensional observation. Summary of the Invention

[0007] To address the long-standing limitations of existing technologies in 3D tomographic imaging, which rely heavily on mechanical scanning methods, traditional mechanical stage or scanning head displacement schemes suffer from inherent physical inertia. This leads to slow axial scanning speeds, significant system vibrations, and a high susceptibility to phase noise, making it difficult to meet the demands of real-time 3D observation. This invention provides a 3D optical scanning holographic system based on electrically adjustable adaptive optics. The technical solution is as follows: A three-dimensional optical scanning holographic system based on an electrically focused adaptive optics device, wherein the connection and optical path layout of each component in the system are as follows: the coherent beam output by the laser is injected into the beam splitter and split into a first beam and a second beam; The first beam propagates along the first optical path: after being reflected by the first plane mirror, the first beam passes sequentially through the electrically focused liquid lens and the first Fourier lens along the optical path, and finally enters the second beam splitter. The second beam propagates along the second optical path: the second beam passes sequentially through the acousto-optic modulator, the second plane mirror, the second pupil, and the second Fourier lens, and finally enters the second beam splitter; Signal acquisition and processing link: After the first beam and the second beam converge at the second beam splitter, they are projected onto the XY scanning galvanometer and focused onto the sample after reflection; the transmitted light is collected by the condenser lens and received by the photodetector; the photodetector is electrically connected to the bandpass filter, and the output of the bandpass filter is connected to the first lock-in amplifier and the second lock-in amplifier respectively; the host is electrically connected to the acousto-optic modulator, the electrically focused liquid lens, the XY scanning galvanometer, and the first and second lock-in amplifiers respectively for synchronous control and image reconstruction. The electrically adjustable liquid lens is positioned at the front focal plane of the first Fourier lens and is used to modulate the beam curvature in real time according to the driving voltage output by the host, thereby achieving continuous or step control of the axial focal position.

[0008] The host performs the following steps to achieve depth-adaptive image reconstruction: Step 1: Determine the current scan depth based on the voltage-depth mapping relationship; Step 2: Calculate the lateral magnification correction factor corresponding to the current depth; Step 3: Generate a dynamic digital decoding mask corresponding to the current depth; Step 4: Perform a convolution operation between the acquired complex hologram and the dynamic digital decoding mask to obtain the corrected tomographic image.

[0009] In step 3 above, generating a dynamic digital decoding mask corresponding to the current depth includes constructing a voltage-dependent dynamic digital decoding mask. The mask mathematically simulates a backpropagation to depth. The free-space impulse response, and after passing through the transverse scale. Correction: (4); In equation (4), This indicates that the driving voltage is Dynamically generated digital decoding mask; Represents the imaginary unit (i.e.) (), used to describe the phase information of the wave field; Indicates the laser wavelength of the system's light source; Indicates the current voltage The corresponding physical scan depth; Represents the two-dimensional horizontal spatial coordinates of the hologram plane; Indicates the corresponding depth The magnification correction factor is used to correct the field scaling effect caused by axial scanning.

[0010] The system constructs a dual-channel interference optical field, in which the signal optical path outputs a spherical wave with controllable curvature through an electrically focused liquid lens, and the reference optical path outputs a plane wave with a fixed frequency shift through an acousto-optic modulator. The wavefront curvature of the signal optical path is adjusted in real time by an electrically focused liquid lens to achieve mechanical axial scanning. The signal light path and the reference light path are combined to form a time-varying Fresnel zone plate, which is then scanned laterally by an XY scanning galvanometer to acquire three-dimensional holographic data of the sample. Three-dimensional holographic information encoded in the carrier frequency is extracted by heterodyne detection and lock-in amplification. Adaptive image reconstruction is performed based on voltage-depth mapping and magnification correction factor to output tomographic images of each depth layer.

[0011] The relationship between the driving voltage and the focal depth of the electrically focused liquid lens is determined by a pre-calibrated voltage-depth curve, which is obtained through experimental measurement and stored in the host computer.

[0012] The beneficial effects of the technical solutions provided in the embodiments of the present invention include at least the following: This invention introduces an electrically adjustable adaptive optics device as the execution unit for axial scanning in the traditional optical scanning holographic optical path. It directly and precisely controls the focal point position through electrical signals, thereby endowing the optical scanning holographic system with axial scanning capability. This achieves a technological leap from "computational refocusing" to "physical focusing". It requires no mechanical movement, has a fast response speed, and has flexible layer selection capability. It can be seamlessly synchronized with lateral scanning, which can improve the imaging speed, interference stability and data acquisition efficiency of the system. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 The optical scanning holographic path diagram of the three-dimensional optical scanning holographic system based on electro-focusing adaptive optics provided by this invention; Figure 2 This is a schematic diagram of the axial scanning principle in a three-dimensional optical scanning holographic system based on an electrically adjustable adaptive optics device provided by the present invention. Figure 3 The flowchart of host signal processing and image reconstruction in the three-dimensional optical scanning holographic system based on electro-focusing adaptive optics provided by the present invention; Figure 4This is a comparison diagram of the two-dimensional cross-sectional intensity distribution of the point spread function (PSF) used in this invention and the existing technology that uses digital refocusing; Figure 5 This is a simulation diagram of the three-dimensional energy distribution of the point spread function (PSF) at the target imaging layer, comparing the present invention with existing technologies.

[0015] The attached figures show a laser 101, a beam splitter 102, an acousto-optic modulator 103, a plane mirror 104, an electrically focused liquid lens 105, a first Fourier lens 106, a plane mirror 107, a second pupil 108, a second Fourier lens 109, a second beam splitter 110, an XY scanning galvanometer 111, a sample 112, a condenser lens 113, a photodetector 114, a bandpass filter 115, a lock-in amplifier 116, a lock-in amplifier 117, and a main unit 118. Detailed Implementation

[0016] The technical solution of the present invention will now be described with reference to the accompanying drawings.

[0017] In embodiments of the present invention, words such as "exemplarily," "for example," etc., are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" in the present invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the word "exemplary" is intended to present the concept in a concrete manner. Furthermore, in embodiments of the present invention, the meaning expressed by "and / or" can be both, or either one.

[0018] In the embodiments of this invention, the terms "image" and "picture" may sometimes be used interchangeably. It should be noted that, without emphasizing the distinction between them, they convey the same meaning. Similarly, the terms "of," "corresponding (relevant)," and "corresponding" may sometimes be used interchangeably. It should be noted that, without emphasizing the distinction between them, they convey the same meaning.

[0019] In this embodiment of the invention, sometimes a subscript such as W1 may be written in a non-subscript form such as W1. When the difference is not emphasized, the meaning they express is the same.

[0020] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0021] This invention provides a three-dimensional optical scanning holographic system based on an electrically adjustable adaptive optics device. The system includes the following optical and electrical components: a laser 101, a beam splitter 102, an acousto-optic modulator 103, a first plane mirror 104, an electrically adjustable liquid lens 105, a first Fourier lens 106, a second plane mirror 107, a second pupil 108, a second Fourier lens 109, a second beam splitter 110, an XY scanning galvanometer 111, a sample 112, a condenser lens 113, a photodetector 114, a bandpass filter 115, a first lock-in amplifier 116, a second lock-in amplifier 117, and a host 118.

[0022] like Figure 1-2 As shown, the connection and optical path layout of each component are as follows: the coherent beam output by the laser 101 enters the beam splitter 102 and is split into a first beam and a second beam.

[0023] First optical path (signal optical path): After being reflected by the first plane mirror 104, the first beam passes sequentially along the optical path through the electrically adjustable liquid lens 105 and the first Fourier lens 106, and finally enters the second beam splitter 110. The electrically adjustable liquid lens 105 is located at the front focal plane of the first Fourier lens 106.

[0024] The optical scanning holographic system is essentially a dual-pupil heterodyne interference imaging device. It is a digital holographic technology that utilizes the dual-pupil heterodyne interference scanning imaging principle. In this application, the electrically focused liquid lens 105 replaces one of the original pupils and becomes the first pupil.

[0025] Second optical path (reference optical path): The second beam passes sequentially along the optical path through the acousto-optic modulator 103, the second plane mirror 107, the second pupil 108, and the second Fourier lens 109, and finally enters the second beam splitter 110.

[0026] Signal acquisition and processing link: The first and second beams converge at the second beam splitter (accelerator) 110 and are projected onto the XY scanning galvanometer 111, where they are reflected and focused onto the sample 112. The transmitted light is collected by the condenser lens 113 and received by the photodetector 114. The photodetector 114 is electrically connected to the bandpass filter 115, and the output of the bandpass filter 115 is connected to the first lock-in amplifier 116 and the second lock-in amplifier 117, respectively. The host 118 is electrically connected to the acousto-optic modulator 103, the electrically focused liquid lens 105, the XY scanning galvanometer 111, and the first lock-in amplifier 116 and the second lock-in amplifier 117, respectively, for synchronous control and data processing.

[0027] Based on the above hardware architecture, the complete implementation process of this invention covers four core stages: light field construction, wavefront phase modulation, holographic scanning recording, and depth correction and reconstruction.

[0028] Light field construction: The system constructs a dual-channel interference light field, in which the signal light path outputs a spherical wave with controllable curvature through an electrically focused liquid lens, and the reference light path outputs a plane wave with a fixed frequency shift through an acousto-optic modulator; The dual-channel interference optical field construction and modulation system constructs two wavefronts with distinctly different properties using a Mach-Zehnder interferometer architecture: Wavefront shaping of the signal optical path, i.e., the first optical path: The laser beam (fundamental frequency) emitted by laser 101 enters the signal optical path after being transmitted through beam splitter 102. The beam is reflected by the first plane mirror 104 and incident on the electrically focused liquid lens 105. At this time, the electrically focused liquid lens 105 is driven by a voltage... Under its influence, it acts as a phase modulator with variable curvature. The modulated spherical wave then passes through the first Fourier lens 106. Since the electrically focused liquid lens is placed at the front focal plane of lens 106, the combined optical path outputs a beam with a curvature radius that varies with voltage at the second beam splitter 110. Precisely controllable spherical waves.

[0029] Frequency shifting and collimation of the reference optical path, i.e., the second optical path: The beam reflected by the beam splitter 102 enters the reference optical path. The acousto-optic modulator 103, driven by radio frequency, generates the beam frequency through an acousto-optic effect. The upconversion frequency shift (i.e., the frequency changes) The frequency-shifted beam is reflected by the second plane mirror 107 and illuminates the second pupil 108 (acting as a spatial filter to remove higher-order diffracted light). After collimation by the second Fourier lens 109, the optical path outputs a plane wave with a fixed frequency shift at the second beam splitter 110.

[0030] Wavefront phase modulation: The wavefront curvature of the signal optical path is adjusted in real time by an electrically focused liquid lens to achieve mechanical axial scanning; Voltage-controlled dynamic wavefront phase modulation is the core component of this invention for achieving mechanical-free axial scanning. In the signal optical path, the electrically focused liquid lens 105 adjusts the voltage output by the host 118. This introduces a dynamic quadratic phase factor into the light beam. The first pupil (i.e., the electrically focusing liquid lens) function... Therefore, it is expressed as a time-varying function: (1); In formula (1): This indicates that the first optical path is driven by a voltage of ComplexPupilFunction at time; The two-dimensional lateral spatial coordinates on the aperture plane of the electrically focused liquid lens (first pupil) 105 are represented. This indicates the real-time driving voltage applied to the electrically focused liquid lens 105; The physical aperture function of the system is usually a circular aperture used to limit the range of light passing through the beam; Represents the imaginary unit ( ); The wavenumber of a laser beam is defined as follows: ,in The wavelength of the laser; This indicates that the electrically adjustable liquid lens 105 is in voltage... Instantaneous focal length under action.

[0031] The signal light path and the reference light path are combined to form a time-varying Fresnel zone plate, which is then scanned laterally by an XY scanning galvanometer to acquire three-dimensional holographic data of the sample. Three-dimensional holographic information encoded in the carrier frequency is extracted by heterodyne detection and lock-in amplification. Time-varying Fresnel zone plate (TD-FZP) scanning and heterodyne detection: Formation of TD-FZP: When the spherical wave of the signal optical path coincides with the plane wave of the reference optical path at the second beam splitter 110, due to the frequency difference between the two beams... They interfere in space to form an intensity at beat frequency Oscillating interference pattern, Time-Dependent Fresnel Zone Plate (TD-FZP).

[0032] Holographic scanning record: Three-dimensional holographic scanning, the TD-FZP light spot was physically projected into the interior of sample 112. Its axial focusing position. Determined by the following formula: (2); In formula (2): Indicates the physical axial depth position of the scanning spot in the sample space; This indicates the fixed focal length of the first Fourier lens 106; Indicates the instantaneous focal length of the electrically adjustable liquid lens 105; It represents the inherent geometric bias in the optical path of the system (i.e., the initial distance of the focal position relative to the sample when the optical power of the electrically focused liquid lens is 0).

[0033] XY scanning galvanometer 111 drives the light spot to move laterally. The sample is scanned using a two-dimensional grating by moving on a plane.

[0034] Holographic data extraction: The light intensity transmitted through sample 112 is collected by condenser lens 113 and converted into photocurrent by photodetector 114. Because the light spot carries... The carrier frequency, the three-dimensional spatial information of the sample is encoded in the AC component of the photocurrent. The host 118 controls the first lock-in amplifier 116 and the second lock-in amplifier 117 to... Using the reference frequency, the photocurrent is quadratured to separate the in-phase component. and orthogonal components Thus obtaining a complex hologram .

[0035] Depth Correction Reconstruction: Adaptive image reconstruction is performed based on voltage-depth mapping and magnification correction factor, outputting tomographic images of each depth layer; Depth-Magnification Adaptive Correction and Image Reconstruction: Because the effective focal length of the system changes when the electrically focused liquid lens zooms, the scanning field of view (FOV) at different depths is scaled (i.e., the breathing effect). To obtain accurate tomographic images and achieve depth-adaptive image reconstruction, this invention implements an adaptive correction and reconstruction algorithm in the host 118, comprising the following steps: Step 1: Determine the current scanning depth based on the voltage-depth mapping relationship. Specifically, for voltage-depth calibration, the system has pre-determined and stored the voltage-depth mapping curve through experiments. Based on the voltage applied to the current scan layer. Calculate the precise physical depth .

[0036] Step 2: Calculate the lateral magnification correction factor corresponding to the current depth. Specifically, the magnification factor calculation is affected by the conical scanning of the beam; changes in depth will lead to changes in lateral magnification. Define the reference depth. Calculate the current lateral magnification correction factor: (3); In formula (3): Indicates depth as Lateral magnification correction factor (dimensionless). This represents the system's preset reference depth plane, where the magnification is defined as 1.

[0037] This factor The scaling of the current hologram relative to the reference plane was quantified.

[0038] Step 3: Generate a dynamic digital decoding mask corresponding to the current depth. Specifically, in generating the dynamic decoding mask, OSH uses a fixed decoding mask, while this invention constructs a voltage-dependent dynamic digital decoding mask. The mask mathematically simulates a backpropagation to depth. The free-space impulse response, and after passing through the transverse scale. Correction: (4); In equation (4), This indicates that the driving voltage is The dynamically generated digital decoding mask is essentially a spatially scaled Fresnel zone plate (FZP) transfer function. Represents the imaginary unit (i.e.) (), used to describe the phase information of the wave field. Indicates the laser wavelength of the system light source (laser 101). Indicates the current voltage The corresponding physical scanning depth (i.e., the distance from the focal point of the scanning spot to the sample). Represents the two-dimensional horizontal spatial coordinates of the hologram plane. Indicates the corresponding depth The magnification correction factor (calculated from step 2 above) is used to correct the field of view (FOV) scaling effect caused by axial scanning.

[0039] Step 4: Perform a convolution operation between the acquired complex hologram and the dynamic digital decoding mask to obtain the corrected tomographic image. Specifically, the acquired complex hologram... With the generated dynamic mask Performing two-dimensional convolution operations in the frequency or spatial domain: (5); In formula (5): This indicates the final reconstructed value located at depth. The complex amplitude distribution of the fault at the location (i.e., the corrected tomographic image). Indicates the system at the driving voltage The original complex hologram data is demodulated and recorded by the first lock-in amplifier 116 and the second lock-in amplifier 117. This represents the symbol for 2D convolution. This operation mathematically simulates the backward propagation process of a hologram and a point spread function (PSF).

[0040] Calculation result This refers to a tomographic image of the target layer that has been defocused and whose size distortion has been corrected.

[0041] The relationship between the driving voltage and the focal depth of the electrically focused liquid lens is determined by a pre-calibrated voltage-depth curve, which is obtained through experimental measurement and stored in the host computer.

[0042] Implementation process of this invention Before operation, the laser 101 is turned on, and the acousto-optic modulator 103 is driven by the host 118 to generate a frequency shift. The initial drive signal of the electrically focused liquid lens 105 is adjusted, and the angles of the first plane mirror 104 and the second plane mirror 107 are adjusted to ensure that the interference light field after beam combining by the second beam splitter 110 can pass through the XY scanning galvanometer 111 and act on the imaging area of ​​the sample 112. Then, the gain of the photodetector 114 and the parameters of the bandpass filter 115 are adjusted to match the signal intensity.

[0043] Based on the target axial depth position of the sample 112 to be detected, a scanning strategy is set in the host 118, the driving voltage (or current) sequence of the electrically focused liquid lens 105 corresponding to different depths is calculated, and the swing angle and scanning frequency of the XY scanning galvanometer 111 are set to cover the required field of view.

[0044] Upon inputting the acquisition command, the XY scanning galvanometer 111 begins to rotate, and the system starts scanning. The laser beam is focused at the target depth by the zoom modulation of the electrically focused liquid lens 105 and performs a lateral scan of the sample 112 under the drive of the XY scanning galvanometer 111. When a depth switch is required, the host 118 changes the drive signal output to the electrically focused liquid lens 105, causing the laser spot focus to jump to the new depth layer for continuous operation. The transmitted light signal is continuously received by the photodetector 114. The host 118 synchronously acquires the data output from the first lock-in amplifier 116 and the second lock-in amplifier 117 and performs image reconstruction. The signal processing and image reconstruction process of the host 118 is as follows: Figure 3 As shown, the transmitted light signal is continuously received by the photodetector 114, and the complex hologram signal after passing through the first lock-in amplifier 116 is input to the second lock-in amplifier 117 and then input to the host. The host control unit reads the current voltage driving voltage of the electrically adjustable liquid lens 105, the host calculation unit calculates the reconstruction depth, calculates the magnification correction factor based on the reconstruction depth, performs several convolution operations based on the magnification correction factor, and outputs optical slices based on the convolution operation results, finally obtaining the three-dimensional reconstructed image.

[0045] This invention employs physical focusing, compared to the point spread function (PSF) two-dimensional cross-sectional intensity distribution method using digital refocusing in existing technologies, for example... Figure 4 As shown, the technical solution provided by this invention significantly improves resolution.

[0046] Simulation results of the three-dimensional energy distribution of the point spread function (PSF) at the target imaging layer in this invention and existing technologies are as follows: Figure 5 As shown, this application differs fundamentally from existing technologies in image quality. Existing technologies (blue dashed line) employ digital refocusing, which, while capable of reconstructing the image, cannot overcome the physical 'defocus' issue, resulting in energy dispersion (low peak value) and spot widening (poor resolution). In contrast, this invention achieves true physical tomography through electronically controlled devices, ensuring a high concentration of energy at the target depth. Therefore, Figure 5 This demonstrates that the proposed solution achieves a higher signal-to-noise ratio and better lateral resolution than existing technologies, which is direct evidence that the present invention solves the technical problems of 'defocus blur' and 'low signal-to-noise ratio'.

[0047] This invention enables high-speed four-dimensional (3D + time) holographic imaging. It utilizes an electrically adjustable adaptive optics device as the active scanning element. In this application, the electrically adjustable adaptive optics device is an electrically adjustable liquid lens, specifically an electrowetting electrically adjustable liquid lens, with a zoom response time in the millisecond range (ms). This is far superior to existing technologies that rely on stepper motors or piezoelectric ceramics to drive the stage for axial scanning, which are limited by mechanical inertia and typically have scanning speeds in the second range. This invention increases the axial scanning speed by 1-2 orders of magnitude, enabling the optical scanning holographic system to capture rapidly changing dynamic biological processes (such as morphological changes accompanying neuronal firing, cell flow, etc.), achieving true real-time four-dimensional microscopic imaging.

[0048] This invention significantly improves the stability of interferometric imaging by employing a completely static mechanical structure (Non-mechanical), thus completely eliminating the vibration sources unavoidable during traditional mechanical axial scanning. This ensures high phase stability of the interference fringes, effectively suppresses phase noise, and results in reconstructed holographic images with higher signal-to-noise ratio and contrast, making it particularly suitable for detecting weak signals sensitive to light intensity.

[0049] This invention features random access capability, significantly improving the detection efficiency of sparse samples. Thanks to the inertia-free nature of electronically controlled zoom, this system possesses the ability for direct addressing at arbitrary depths. Users can programmatically define discontinuous regions of interest (ROIs), and the system can instantly switch between different depth layers without sequentially scanning invalid regions in between. This not only eliminates mechanical backtracking errors but also greatly reduces the acquisition and processing of redundant data, significantly improving the detection efficiency for sparse or layered samples.

[0050] This invention establishes the advantages of physical tomography, solving the problems of defocusing and resolution degradation (an additional advantage). Unlike traditional digital holography that relies solely on computational refocusing, this invention introduces a physical zoom mechanism. By adjusting the focus in real time, it ensures that the point of highest energy concentration of the scanning spot (the beam waist) is always physically aligned with the current tomographic position. This means that the system can maintain optimal numerical aperture (NA) and optical transfer function (OTF) at all imaging depths, thereby achieving uniform and optimal lateral resolution throughout the entire three-dimensional space, avoiding the severe resolution degradation problem that occurs when using simple digital refocusing at locations far from the focal plane.

[0051] The above embodiments can be implemented, in whole or in part, by software, hardware (such as circuits), firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, all or part of the processes or functions described in the embodiments of the present invention are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more sets of available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium. A semiconductor medium can be a solid-state drive.

[0052] It should be understood that the term "and / or" in this article 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, or B existing alone. A and B can be singular or plural. Additionally, the character " / " in this article generally indicates an "or" relationship between the preceding and following related objects, but it can also represent an "and / or" relationship. Please refer to the context for a more accurate understanding.

[0053] In this invention, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of a single item or a plurality of items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be a single item or multiple items.

[0054] It should be understood that, in various embodiments of the present invention, the order of the above-mentioned process numbers does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0055] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0056] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the devices, apparatuses, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0057] In the several embodiments provided by this invention, it should be understood that the disclosed devices, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another device, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0058] 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.

[0059] In addition, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0060] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0061] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A three-dimensional optical scanning holography system based on electrically focused adaptive optical device, characterized in that, The connection of each component in the system and the layout of the optical path are as follows: the coherent light beam output by the laser is incident into the beam splitter and is divided into a first light beam and a second light beam; The first light beam propagates along a first optical path: after being reflected by the first plane mirror, the first light beam sequentially passes through the electrically tunable liquid lens and the first Fourier lens along the optical path, and finally is incident into the second beam splitter; The second light beam propagates along a second optical path: the second light beam sequentially passes through the acousto-optic modulator, the second plane mirror, the second pupil and the second Fourier lens along the optical path, and finally is incident into the second beam splitter; The signal acquisition and processing link: after the first light beam and the second light beam converge at the second beam splitter, they are projected onto the XY scanning galvanometer and are focused on the sample after being reflected; the transmitted light is collected by the condenser lens and is received by the photodetector; the photodetector is electrically connected to the band-pass filter, and the output end of the band-pass filter is respectively connected to the first lock-in amplifier and the second lock-in amplifier; the host computer is electrically connected to the acousto-optic modulator, the electrically tunable liquid lens, the XY scanning galvanometer and the first lock-in amplifier and the second lock-in amplifier for synchronous control and image reconstruction; The electrically tunable liquid lens is arranged at the front focal plane of the first Fourier lens, and is used for modulating the curvature of the light beam in real time according to the driving voltage output by the host computer, so as to realize continuous or step-by-step control of the axial focal point position.

2. The three-dimensional optical scanning holography system based on electrically focused adaptive optics according to claim 1, wherein, The host computer performs the following steps to realize depth-adaptive image reconstruction: Step 1: determining the current scanning depth according to the voltage-depth mapping relationship; Step 2: calculating the lateral magnification correction factor corresponding to the current depth; Step 3: generating a dynamic digital decoding mask corresponding to the current depth; Step 4: performing convolution operation on the acquired complex hologram and the dynamic digital decoding mask to obtain the corrected tomographic image.

3. The three-dimensional optical scanning holography system based on electrically focused adaptive optics according to claim 2, wherein, In step 3 above, generating a dynamic digital decoded mask corresponding to the current depth includes constructing a voltage-dependent dynamic digital decoded mask ; this mask mathematically models a free-space impulse response propagating backwards to depth , and corrected for lateral dimensions : （4）； In formula (4), represents a dynamic digital decoded mask generated when the driving voltage is ; represents an imaginary unit (i.e. ), used to describe the phase information of the wave field; represents the laser wavelength of the system light source; represents the physical scanning depth corresponding to the current voltage ; represents the two-dimensional transverse spatial coordinates of the hologram plane; represents the magnification correction factor corresponding to the depth , used to correct the field-of-view scaling effect caused by axial scanning.

4. The three-dimensional optical scanning holography system based on electrically focused adaptive optics of claim 1, wherein, The system constructs a double-channel interference optical field, in which the signal light path outputs a spherical wave with controllable curvature through the electrically tunable liquid lens, and the reference light path outputs a plane wave with fixed frequency shift through the acousto-optic modulator; The wavefront curvature of the signal light path is adjusted in real time through the electrically tunable liquid lens, so as to realize mechanical-free axial scanning; The signal light path and the reference light path are combined to form a time-varying Fresnel zone plate, which is scanned laterally through the XY scanning galvanometer, so as to perform three-dimensional holographic data acquisition on the sample; The three-dimensional holographic information encoded in the carrier frequency is extracted through heterodyne detection and lock-in amplification; Based on the voltage-depth mapping and the magnification correction factor, adaptive image reconstruction is performed to output the tomographic images of each depth layer.

5. The three-dimensional optical scanning holography system based on electrically focused adaptive optics according to claim 4, wherein, The relationship between the driving voltage of the electrically tunable liquid lens and the focal depth is determined by the voltage-depth curve calibrated in advance, which is obtained through experimental measurement and stored in the host computer.

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