Phased-Array Common-Path Interference Single-Pixel Detection for Implementing Spatial Wavefront Sensing Device and Method

Abstract

The present invention belongs to the cross field of spatial wavefront measurement and single-pixel imaging. The existing single-pixel imaging technology for wavefront sensing has defects such as complexity, poor stability, loss of imaging resolution, and reduction of light utilization efficiency, resulting in low performance of complex-field imaging. The present invention provides a device and method for realizing spatial wavefront sensing by phased-array common-path interference single-pixel detection. By utilizing the structural characteristics and pure-phase modulation characteristics of the phased array and combining with single-pixel detection technology, the intensity ratio of the signal light and the reference light in the interference is flexibly adjusted to achieve higher-performance measurement of the wavefront complex amplitude. The device of the present invention is simple, has high stability, significantly improved imaging resolution, and has the advantages of high light energy utilization efficiency, flexibility, convenience, and simple structure. It is suitable for wavefront complex amplitude measurement in a wide spectrum, especially in the case where array detectors are expensive or do not exist yet, and has broad application prospects in fields such as quantitative phase microscopy imaging, adaptive optics, imaging through scattering media, and quantum light field measurement.

Description

Technical Field

[0001] The present invention belongs to the cross - field of spatial wavefront measurement and single - pixel imaging. More specifically, it relates to a device and method for realizing spatial wavefront sensing by phased - array common - path interference single - pixel detection. Background Art

[0002] Single - pixel imaging is a new emerging computational imaging technology, which has advantages such as high detection sensitivity, wide spectral response rate, and precise time resolution. When single - pixel imaging is combined with interferometry, it can further detect spatial wavefront information. Different from traditional array - type detector wavefront sensing, single - pixel detection for wavefront sensing mainly uses complex - valued coefficients corresponding to a series of measurement patterns to reconstruct the wavefront. Benefiting from the high sensitivity and wide spectrum of single - pixel detectors, this technology is suitable for wavefront complex - amplitude measurement in the wide spectrum, especially in cases where array detectors are expensive or do not yet exist, and has broad application prospects in fields such as quantitative phase microscopy, adaptive optics, imaging through scattering media, and quantum light - field measurement.

[0003] The complex - valued coefficient spectrum of the wavefront obtained by single - pixel detection is mainly realized through interferometric measurement. Currently, there are two implementation methods for single - pixel detection based on interferometric measurement to realize wavefront sensing. One is to use a Mach - Zehnder or other two - path interferometer to realize two - path phase - shifting interference, introducing an additional reference optical path in the system. This method increases the complexity of the system device and has poor anti - interference ability; the other is to use the method of super - pixels and spatial partitioning to realize common - path phase - shifting interference. These methods do not fully utilize the spatial bandwidth - product of the phased - array, and detect the first - order diffraction of the phased - array, resulting in a decrease in imaging resolution and a reduction in light utilization efficiency, so the wavefront imaging performance is not high. Summary of the Invention

[0004] The device and method of the present invention are based on phased - array common - path interference single - pixel detection to realize spatial wavefront sensing. The purpose is to disclose a device and method for realizing spatial wavefront sensing by combining the structural characteristics and pure - phase modulation characteristics of the phased - array for common - path interference with single - pixel detection. Its characteristics are that it can freely and flexibly adjust the intensity ratio of the signal light and the reference light of the interference, fully utilize the spatial bandwidth - product of the phased - array, and realize higher - resolution measurement of the wavefront complex - amplitude. It has the advantages of simple structure, higher measurement resolution, higher light energy utilization efficiency, and flexible adjustment. Compared with using a Mach - Zehnder or other two - path interferometer to realize single - pixel wavefront measurement, the device is simpler and has higher stability; compared with the existing methods of using super - pixels and spatial partitioning to realize single - pixel wavefront measurement, the imaging resolution is increased by more than twice, and it has the advantages of higher light utilization rate and more flexible system.

[0005] To achieve the above - mentioned purpose, the device and method of the present invention are realized through the following technical solutions:

[0006] An apparatus for realizing spatial wavefront sensing by phased-array common-path interference single-pixel detection uses the structural characteristics and pure phase modulation characteristics of the phased array for common-path interference, combines single-pixel detection, and realizes spatial wavefront sensing. It includes a first lens, a second lens, a phased-array common-path phase-shifting interference structure, a third lens, a pinhole, and a detector. The first lens, the second lens, the third lens, the pinhole, and the detector are arranged along the optical axis direction. Among them, the first lens and the second lens form a 4f system, and its function is to flexibly adjust the actual measurement contact surface to the plane where the wavefront to be measured is located; the working surface of the phased array is placed on the confocal plane of the 4f system and the third lens; the pinhole is placed at the rear focal position of the third lens, close to the detector 6; the phased-array common-path interference structure includes a half-wave plate, a phased array, and a polarizer. The half-wave plate and the polarizer are placed on both sides or the same side of the working surface of the phased array 32 perpendicular to the optical axis along the optical axis direction respectively.

[0007] Furthermore, the phased array is a transmissive phased array or a reflective phased array; if the phased array is a transmissive phased array, the half-wave plate and the polarizer are placed on both sides of the working surface of the phased array perpendicular to the optical axis along the optical axis direction. The first lens, the second lens, the phased-array common-path interference structure, the third lens, the pinhole, and the detector are arranged in sequence along the optical axis direction. The first lens, the second lens, the phased-array common-path interference structure, the third lens, the pinhole, and the detector are all perpendicular to the optical axis; if the phased array is a reflective phased array, the half-wave plate and the polarizer are placed on the same side of the working surface of the phased array perpendicular to the optical axis along the optical axis direction. The first lens, the second lens, the phased-array common-path interference structure, the third lens, the pinhole, and the detector are arranged in sequence along the optical axis direction. The first lens, the second lens, the phased-array common-path interference structure, the third lens, the pinhole, and the detector are all perpendicular to the optical axis.

[0008] Furthermore, the phased array is used to carry the designed phase distribution, and plays an expected modulation role on the transmitted wavefront. The polarization direction is horizontal polarization or vertical polarization; the size of the pinhole satisfies the relationship r≤1.27λf / d with the wavelength and diameter of the light beam incident on the third lens and the focal length of the third lens, where λ is the wavelength of the light beam, f is the focal length of the third lens, and d is the diameter of the light beam.

[0009] A method for realizing spatial wavefront sensing by phased-array common-path phase-shifting interference single-pixel detection is realized by using the above-mentioned apparatus for realizing spatial wavefront sensing by phased-array common-path interference single-pixel detection. The specific steps are as follows:

[0010] Step 1: Relay the target spatial wavefront to the working surface of the phased array by the 4f system composed of the first lens and the second lens. The initial phase distribution of the phased array is set to the non-modulation mode, and the size of the pinhole is determined according to the relationship r≤1.27λf / d that the wavelength and diameter of the light beam incident on the third lens and the focal length of the third lens satisfy.

[0011] Step 2: Adjust the directions of the polarizer and the half-wave plate so that the non-modulated beam and the modulated beam of the phased array 32 form a common-path interference;

[0012] Step 3: Configure the initial parameters of the device for single-pixel detection of common-path interference of the phased array to achieve spatial wavefront sensing: spatial wavefront imaging resolution M×N, single-pixel imaging sampling rate Number of phase-shifting steps;

[0013] Step 4: Load the modulation pattern onto the phased array, and the detector collects the signal intensity; shift the modulation patterns generated by single-pixel imaging by phase respectively, and load them onto the phased array in sequence. At the same time, the detector collects the signal intensity values of the center point of the Fourier plane corresponding to each pattern;

[0014] Step 5: Reconstruct the target spatial wavefront: Obtain the complex coefficient spectrum of the target spatial wavefront based on the phase-shifting technique, and use the single-pixel reconstruction algorithm to restore the target spatial wavefront.

[0015] Furthermore, in Step 2, the setting for forming the common-path interference is selected from one of the following three methods:

[0016] (i) Adjust the half-wave plate so that the polarization direction of the wavefront to be measured is the same as the polarization direction of the phased array, and adjust the polarizer direction to be the same as the half-wave plate direction, so that the wavefront reflected / transmitted and modulated by the pixel area of the phased array and the unmodulated wavefront directly reflected / transmitted by the pixel gap of the phased array pass through the polarizer to form a common-path interference;

[0017] (ii) Adjust the half-wave plate so that the polarization direction of the wavefront to be measured forms an inclined angle with the polarization direction of the phased array, and adjust the polarizer direction to be perpendicular to the half-wave plate direction, so that the wavefront reflected / transmitted and modulated by the pixel area of the phased array and the unmodulated wavefront reflected / transmitted by the pixel area of the phased array pass through the polarizer to form a common-path interference;

[0018] (iii) Adjust the half-wave plate so that the polarization direction of the wavefront to be measured forms an inclined angle with the polarization direction of the phased array, and adjust the polarizer direction to be the same as the half-wave plate direction, so that the wavefront reflected / transmitted and modulated by the pixel area of the phased array, the unmodulated wavefront reflected / transmitted by the pixel area of the phased array, and the unmodulated wavefront directly reflected by the pixel gap of the phased array all pass through the polarizer to form a common-path interference.

[0019] Furthermore, the multi-step phase shifting in Step 3 includes: three-step phase shifting or more than three-step phase shifting.

[0020] A method for realizing spatial wavefront sensing by combining single-pixel detection of common-path interference of a phased array with Hilbert transform, which is realized by using the device for single-pixel detection of common-path interference of a phased array to achieve spatial wavefront sensing described above. The specific steps are as follows:

[0021] Step 1: Relay the target spatial wavefront to the phased array working surface through a 4f system composed of a first lens and a second lens. Set the initial phase distribution of the phased array to the non-modulation mode. Determine the size of the pinhole according to the relationship r≤1.27λf / d that the wavelength and diameter of the light beam incident on the third lens and the focal length of the third lens satisfy.

[0022] Step 2: Configure the initial parameters of the device for spatial wavefront sensing by using phased array common-path interference single-pixel detection: the spatial wavefront imaging resolution M×N, the single-pixel imaging sampling rate The interference holographic angle;

[0023] Step 3: Load a digital concave conical grating and modulation modes on the phased array: Form a fixed phase difference between the modulated beam of the phased array and the unmodulated beam of the phased array through the introduced digital concave conical grating, and converge on the optical axis to form common-path interference.

[0024] Step 4: The detector collects the interference signal intensity values at the center points of the Fourier planes corresponding to each mode.

[0025] Step 5: Restore the target hologram by the single-pixel reconstruction algorithm, and then reconstruct the target spatial wavefront according to the Hilbert transform algorithm.

[0026] Further, the source of the unmodulated beam of the phased array is the unmodulated light in the pixel gaps of the phased array or the unmodulated light that is polarization orthogonal to the pure phase modulation of the phased array, or a combination of the two.

[0027] Further, the phased array is a pure phase modulator indirectly realized by a digital micromirror array, a ferroelectric liquid crystal spatial light modulator, and an amplitude liquid crystal spatial light modulator through the lee method or the superpixel method, or a pure phase liquid crystal spatial light modulator.

[0028] Further, the modulation basis modes include: basis modes such as Hadamard transform, discrete cosine transform, and Fourier transform.

[0029] In summary, the present invention has the following beneficial effects:

[0030] The present invention provides a device and method for realizing spatial wavefront sensing by phased array common-path interference single-pixel detection. By using the common-path interference of the structural characteristics and pure phase modulation characteristics of the phased array, combined with single-pixel detection, a device and method for realizing spatial wavefront sensing are achieved. The intensity ratio of the signal light and the reference light of the interference can be freely and flexibly adjusted, and the spatial product width of the phased array is fully utilized to achieve higher-resolution measurement of the wavefront complex amplitude. The present invention has the advantages of simple structure, high measurement resolution, high light energy utilization efficiency, and flexible adjustment. Compared with the dual-path interferometers such as Mach-Zehnder for realizing single-pixel wavefront measurement, the device of the present invention is simpler and has higher stability; compared with the existing methods for realizing single-pixel wavefront measurement by superpixels and spatial partitioning, the imaging resolution is increased by more than twice, and it has the advantages of higher light utilization rate and more flexible system. The present invention can also be extended to wider bands, such as infrared, terahertz, X-ray and other bands, especially for the measurement of wavefront complex amplitude in the case where array detectors are expensive or do not exist yet, and has broad application prospects in the fields of quantitative phase microscopy, adaptive optics, imaging through scattering media, quantum light field measurement, etc. Description of the Drawings

[0031] Figure 1 Schematic diagram of a device for realizing spatial wavefront sensing by transmissive phased array common-path interference single-pixel detection;

[0032] Figure 2 Schematic diagram of a device for realizing spatial wavefront sensing by reflective phased array common-path interference single-pixel detection;

[0033] Figure 3 Schematic diagram of a method for forming common-path interference by a transmissive phased array common-path interference structure;

[0034] Figure 4 Schematic diagram of a method for forming common-path interference by a reflective phased array common-path interference structure;

[0035] Figure 5 Amplitude and phase distribution diagram of a target spatial wavefront;

[0036] Figure 6 Amplitude and phase distribution diagram of the realized target spatial wavefront.

[0037] In the figure, 1 is the first lens, 2 is the second lens, 3 is the phased array common-path interference structure, 4 is the third lens, 5 is the pinhole, 6 is the detector, 31 is the half-wave plate, 32 is the phased array, and 33 is the polarizer. Specific Embodiment

[0038] The present invention will be further described in detail below with reference to the accompanying drawings.

[0039] It should be noted that for the convenience of description, the description of directions in the following text is consistent with the directions of the accompanying drawings themselves, but does not limit the structure of the present invention.

[0040] As shown Figures 1 to 6 in the figure, the present invention discloses a device for realizing spatial wavefront sensing by phased array common-path interference single-pixel detection, which mainly consists of a first lens 1, a second lens 2, a phased array common-path phase-shifting interference structure 3, a third lens 4, a pinhole 5 and a detector 6. The first lens 1, the second lens 2, the third lens 4, the pinhole 5 and the detector 6 are successively placed perpendicular to the optical axis along the optical axis direction. Among them, the first lens 1 and the second lens 2 form a 4f system, and its function is to flexibly adjust the actual measurement contact surface (i.e., the phased array action surface) to the plane where the wavefront to be measured is located; the action surface of the phased array 32 is placed on the confocal plane of the 4f system composed of the first lens 1 and the second lens 2 and the third lens 4, that is, the focal planes of the 4f system and the third lens coincide; the pinhole 5 is placed at the rear focal position of the third lens 4 and is close to the detector 6.

[0041] The phased array common-path interference structure 3 proposed by the present invention mainly consists of a half-wave plate 31, a phased array 32 and a polarizer 33. The half-wave plate 31 and the polarizer 33 are placed on both sides or on the same side of the action surface of the phased array 32 perpendicular to the optical axis along the optical axis direction.

[0042] The phased array 32 is a transmissive phased array or a reflective phased array; if the phased array 32 is a transmissive phased array, the half-wave plate 31 and the polarizer 33 are placed on both sides of the action surface of the phased array 32 perpendicular to the optical axis along the optical axis direction. The first lens 1, the second lens 2, the phased array common-path interference structure 3, the third lens 4, the pinhole 5 and the detector 6 are successively placed along the optical axis direction and are all perpendicular to the optical axis.

[0043] If the phased array 32 is a reflective phased array, the half-wave plate 31 and the polarizer 33 are placed on the same side of the action surface of the phased array 32 perpendicular to the optical axis along the optical axis direction. The first lens 1, the second lens 2, the phased array common-path interference structure 3, the third lens 4, the pinhole 5 and the detector 6 are placed along the optical axis direction and are respectively perpendicular to the optical axis.

[0044] The phased array 32 is used to carry the designed phase distribution and play an expected modulation role on the transmitted wavefront. The polarization direction is horizontal polarization or vertical polarization, and the polarization direction depends on the device processing design. The polarization direction is generally horizontal polarization; the aperture r of the pinhole 5 satisfies the relationship r ≤ 1.27λf / d with the wavelength and diameter of the light beam incident on the third lens and the focal length of the third lens, where λ is the wavelength of the light beam, f is the focal length of the third lens, and d is the diameter of the light beam.

[0045] Based on the above device for realizing spatial wavefront sensing by phased array common-path interference single-pixel detection, the present invention also discloses a method for realizing spatial wavefront sensing by phased array common-path phase-shifting interference single-pixel detection, and the specific steps are as follows:

[0046] Step 1: Relay the target spatial wavefront to the action surface of the phased array 32 through the 4f system composed of the first lens 1 and the second lens 2, that is, relay the spatial wavefront to be measured to the action surface of the phased array 32. The initial phase distribution of the phased array 32 is set to the non-modulation mode. According to the wavelength and diameter of the light beam incident on the third lens 4 and the focal length of the third lens 4 satisfying the relationship r≤1.27λf / d, determine the size of the pinhole 5.

[0047] Step 2: Adjust the directions of the polarizer and the 1 / 2 wave plate so that the non-modulated light beam and the modulated light beam of the phased array 32 form common-path interference. The setting for forming common-path interference can be selected from the following three methods:

[0048] (i) Adjust the 1 / 2 wave plate 31 so that the polarization direction of the wavefront to be measured is the same as the polarization direction of the phased array 32, and adjust the direction of the polarizer 33 to be the same as the direction of the 1 / 2 wave plate 31. Make the wavefront reflected / transmitted and modulated by the pixel area of the phased array 32 and the unmodulated wavefront directly reflected / transmitted by the pixel gap of the phased array 32 pass through the polarizer 33 to form common-path interference.

[0049] (ii) Adjust the 1 / 2 wave plate 31 so that the polarization direction of the wavefront to be measured forms an inclined angle with the polarization direction of the phased array 32. The angle can be set arbitrarily, and the specific angle is reasonably adjusted according to the actual experimental situation and requirements. Adjust the direction of the polarizer 33 to be perpendicular to the direction of the 1 / 2 wave plate 31. Make the wavefront reflected / transmitted and modulated by the pixel area of the phased array 32 and the unmodulated wavefront reflected / transmitted by the pixel area of the phased array 32 pass through the polarizer 33 to form common-path interference.

[0050] (iii) Adjust the 1 / 2 wave plate 31 so that the polarization direction of the wavefront to be measured forms an inclined angle with the polarization direction of the phased array 32, and adjust the direction of the polarizer 33 to be the same as the direction of the 1 / 2 wave plate 31. Make the wavefront reflected / transmitted and modulated by the pixel area of the phased array 32, the unmodulated wavefront reflected / transmitted by the pixel area of the phased array 32, and the unmodulated wavefront directly reflected by the pixel gap of the phased array 32 all pass through the polarizer 33 to form common-path interference.

[0051] Step 3: Configure the initial parameters of the device for realizing spatial wavefront sensing by phased array common-path interference single-pixel detection. The spatial wavefront imaging resolution is M×N, and the single-pixel imaging sampling rate Phase-shifting steps.

[0052] Step 4: Load the modulation mode to the phased array 32, and the detector 6 collects the signal intensity. The The phase of each modulation mode is shifted, and they are sequentially loaded onto the phased array 32. Meanwhile, the detector 6 collects the signal intensity values of the center points in the Fourier plane corresponding to each mode.

[0053] Step Five: Reconstruct the target spatial wavefront: Obtain the complex coefficient spectrum of the target spatial wavefront based on the phase-shifting technique, and use the single-pixel reconstruction algorithm to restore the target spatial wavefront.

[0054] The phase shift can adopt three-step phase shift or more than three-step phase shift. Taking one of the common multi-step phase-shifting methods, four-step phase shift, as an example, in the following embodiments, the examples in Embodiment 1 and Embodiment 2 have four-step phase shift.

[0055] Based on the device for realizing spatial wavefront sensing by phased array common-path interference single-pixel detection, the present invention also discloses a method for realizing spatial wavefront sensing by combining phased array common-path interference single-pixel detection with Hilbert transform. The specific steps are as follows:

[0056] Step One: Relay the target spatial wavefront to the action surface of the phased array 32 through the 4f system composed of the first lens 1 and the second lens 2. The initial phase distribution of the phased array 32 is set to the non-modulation mode. Determine the size of the pinhole 5 according to the relationship r ≤ 1.27λf / d, where λ is the wavelength and diameter of the light beam incident on the third lens 4, and f is the focal length of the third lens 4.

[0057] Step Two: Configure the initial parameters of the device for realizing spatial wavefront sensing by phased array common-path interference single-pixel detection: the spatial wavefront imaging resolution M×N, the single-pixel imaging sampling rate The interference holographic angle.

[0058] Step Three: Load a digital concave conical grating and a number of modulation modes on the phased array 32. A fixed phase difference is formed between the modulated light beam of the phased array 32 passing through the digital concave conical grating and the unmodulated light beam of the phased array 32, and they are converged on the optical axis to form common-path interference. Among them, the source of the unmodulated light beam of the phased array 32 is selected from the following three options according to actual needs: (1) the unmodulated light in the pixel gap of the phased array 32; (2) the unmodulated light that is orthogonally polarized to the pure phase modulation of the phased array 32; (3) a combination of the two.

[0059] Step Four: The detector 6 collects the interference signal intensity values of the center points in the Fourier plane corresponding to each mode.

[0060] Step Five: Restore the target hologram by the single-pixel reconstruction algorithm, and then reconstruct the target spatial wavefront according to the Hilbert transform algorithm.

[0061] The phased array is an indirect implementation of a pure phase modulator by a digital micromirror array, a ferroelectric liquid crystal spatial light modulator, and an amplitude liquid crystal spatial light modulator through the Lee method or the superpixel method, or a pure phase liquid crystal spatial light modulator. Taking the liquid crystal spatial light modulator, one of the common reflective optical phased arrays, as an example, the device and method for realizing spatial wavefront sensing by the common-path interference single-pixel detection of the liquid crystal spatial light modulator are used in the wavefront sensing occasion with low optical power.

[0062] The modulation basis modes include: basis modes such as Hadamard transform, discrete cosine transform, and Fourier transform. Taking the Hadamard basis, one of the common bases for single-pixel imaging modulation, as an example, the device and method for realizing spatial wavefront sensing by the common-path interference single-pixel detection of the phased array are used in the phased array occasion with a binary modulation mode. In the following embodiments, the modulation modes in Embodiment 1, Embodiment 2, and Embodiment 3 are examples of the Hadamard basis mode.

[0063] The device and method for realizing spatial wavefront sensing by combining single-pixel detection are characterized by the ability to freely and flexibly adjust the intensity ratio of the signal light and the reference light of the interference, make full use of the spatial bandwidth product of the phased array, and realize higher-resolution measurement of the wavefront complex amplitude. It has the advantages of simple structure, high measurement resolution, high light energy utilization efficiency, and flexible adjustment, and is suitable for wavefront complex amplitude measurement in a wide spectrum, especially in the case where array detectors are expensive or do not exist yet. The present invention has broad application prospects in the fields of quantitative phase microscopy, adaptive optics, imaging through scattering media, quantum light field measurement, etc.

[0064] Embodiment 1: This embodiment will be described with reference to the figures. This embodiment is a device for realizing spatial wavefront sensing by the common-path interference single-pixel detection of a phased array, which mainly consists of a first lens 1, a second lens 2, a phased array common-path phase-shifting interference structure 3, a third lens 4, a pinhole 5, and a detector 6. The first lens 1, the second lens 2, the third lens 4, the pinhole 5, and the detector 6 are placed along the optical axis direction. Among them, the first lens 1 and the second lens 2 form a 4f system, and its function is to flexibly adjust the actual measurement contact surface (i.e., the phased array action surface) to the plane where the wavefront to be measured is located; the action surface of the phased array 32 is placed on the confocal plane of the 4f system composed of the first lens 1 and the second lens 2 and the third lens 4; the pinhole 5 is placed at the rear focal position of the third lens 4 and is close to the detector 6.

[0065] The phased array common-path interference structure 3 proposed by the present invention mainly consists of a half-wave plate 31, a phased array 32, and a polarizer 33. The half-wave plate 31 and the polarizer 33 are placed on both sides or on the same side of the phased array 32 action surface perpendicular to the optical axis along the optical axis direction.

[0066] The phased array 32 is a transmissive phased array or a reflective phased array; if the phased array 32 is a transmissive phased array, the half-wave plate 31 and the polarizer 33 are placed on both sides of the action surface of the phased array 32 perpendicular to the optical axis along the optical axis direction, and the first lens 1, the second lens 2, the phased array common-path interference structure 3, the third lens 4, the pinhole 5 and the detector 6 are placed along the optical axis direction and perpendicular to the optical axis respectively.

[0067] If the phased array 32 is a reflective phased array, the half-wave plate 31 and the polarizer 33 are placed on the same side of the action surface of the phased array 32 perpendicular to the optical axis along the optical axis direction, and the first lens 1, the second lens 2, the phased array common-path interference structure 3, the third lens 4, the pinhole 5 and the detector 6 are placed along the optical axis direction and perpendicular to the optical axis respectively.

[0068] The phased array 32 is used to carry the designed phase distribution and plays an expected modulation role on the transmitted wavefront. The polarization direction is generally horizontal polarization; the size of the pinhole 5 satisfies the relationship r ≤ 1.27λf / d with the wavelength and diameter of the light beam incident on the third lens 4 and the focal length of the third lens 4, where λ is the wavelength of the light beam, f is the focal length of the third lens 4, and d is the diameter of the light beam.

[0069] Embodiment 2: Combining Figure 1 、 Figure 2 、 Figure 3 and Figure 4 This embodiment is described. This embodiment is a step of a method for realizing spatial wavefront sensing by phased array common-path phase-shifting interference single-pixel detection, as follows:

[0070] Step 1: Relay the target spatial wavefront to the action surface of the phased array 32 through the 4f system composed of the first lens 1 and the second lens 2. The initial phase distribution of the phased array 32 is set to the non-modulation mode. According to the relationship r ≤ 1.27λf / d satisfied by the wavelength and diameter of the light beam incident on the third lens 4 and the focal length of the third lens 4, the size of the pinhole 5 is determined.

[0071] Step 2: Adjust the directions of the polarizer and the half-wave plate so that the non-modulated light beam and the modulated light beam of the phased array 32 form common-path interference. Among them, the setting for forming common-path interference can be selected from the following three methods.

[0072] (i) Adjust the half-wave plate 31 so that the polarization direction of the wavefront to be measured is the same as the polarization direction of the phased array 32, and adjust the direction of the polarizer 33 to be the same as the direction of the half-wave plate 31. Make the wavefront reflected / transmitted and modulated by the pixel area of the phased array 32 and the unmodulated wavefront directly reflected / transmitted by the pixel gap of the phased array 32 pass through the polarizer 33 to form common-path interference.

[0073] (ii) Adjust the half-wave plate 31 so that the polarization direction of the wavefront to be measured forms an inclined angle with the polarization direction of the phased array 32, and adjust the direction of the polarizer 33 to be perpendicular to the direction of the half-wave plate 31. Make the wavefront reflected / transmitted and modulated by the pixel region of the phased array 32 and the wavefront reflected / transmitted without being modulated by the pixel region of the phased array 32 pass through the polarizer 33 to form a common-path interference.

[0074] (iii) Adjust the half-wave plate 31 so that the polarization direction of the wavefront to be measured forms an inclined angle with the polarization direction of the phased array 32, and adjust the direction of the polarizer 33 to be consistent with the direction of the half-wave plate 31. Make the wavefront reflected / transmitted and modulated by the pixel region of the phased array 32, the wavefront reflected / transmitted without being modulated by the pixel region of the phased array 32, and the wavefront directly reflected without being modulated by the pixel gap of the phased array 32 all pass through the polarizer 33 to form a common-path interference.

[0075] Step 3: Configure the initial parameters of the detection system. The spatial wavefront imaging resolution is M×N, and the single-pixel imaging sampling rate Number of phase-shifting steps.

[0076] Step 4: Load the modulation pattern into the phased array 32, and the detector 6 collects the signal intensity. Shift the modulation patterns generated by single-pixel imaging respectively, and sequentially load them into the phased array 32. At the same time, the detector 6 collects the signal intensity values of the center point of the Fourier plane corresponding to each pattern.

[0077] Step 5: Reconstruct the target spatial wavefront. Obtain the complex coefficient spectrum of the target spatial wavefront according to the phase-shifting technology, and use the single-pixel reconstruction algorithm to restore the target spatial wavefront.

[0078] Embodiment 3: Combine Figure 1 、 Figure 2 、 Figure 3 and Figure 4 to illustrate this embodiment. This embodiment is a step of a spatial wavefront sensing method that combines phased array common-path interference single-pixel detection with Hilbert transform, as follows:

[0079] Step 1: Relay the target spatial wavefront to the working surface of the phased array 32 through the 4f system composed of the first lens 1 and the second lens 2. Set the initial phase distribution of the phased array 32 to the non-modulation mode, and determine the size of the pinhole 5 according to the relationship r≤1.27λf / d between the wavelength and diameter of the light beam incident on the third lens 4 and the focal length of the third lens 4.

[0080] Step 2: Configure the initial parameters of the detection system. The spatial wavefront imaging resolution is M×N, and the single-pixel imaging sampling rate Interference holographic angle.

[0081] Step 3: Load the digital concave cone grating and A modulation mode. A fixed phase difference is formed between the modulated light beam of the phased array 32 and the unmodulated light beam of the phased array 32 through the introduced digital concave cone grating, and the light beams are converged on the optical axis to form common-path interference, wherein the source of the unmodulated light beam of the phased array 32 can be the unmodulated light in the pixel gap of the phased array 32, or the unmodulated light with polarization orthogonal to the pure phase modulation of the phased array 32, or a combination of the two.

[0082] Step 4: The detector 6 collects the interference signal intensity value at the center point of the Fourier plane corresponding to each mode.

[0083] Step 5: Restore the target hologram using the single-pixel reconstruction algorithm, and then reconstruct the target spatial wavefront based on the Hilbert transform algorithm.

[0084] The phased array 32 in the first, second and third embodiments is an example of a liquid crystal spatial light modulator.

[0085] Implementation method 4: Take the wavefront imaging of a space to be measured with a circular amplitude distribution and a triangular phase distribution as an example. Figure 5 As shown, in this embodiment, the target space wavefront needs to be relayed to the phased array 32 action surface through the 4f system in the first embodiment; then, the wavefront imaging is performed according to the steps of the second embodiment or the third embodiment, according to Figure 3 and Figure 4 Common-path interference is formed. The reconstructed wavefront amplitude and phase distribution obtained by the three methods are as follows Figure 6 shown.

[0086] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. An apparatus for realizing spatial wavefront sensing by phased array common-path interference single-pixel detection, characterized in that Common-path interference is carried out by utilizing the structural characteristics of the phased array and the pure-phase modulation characteristics, and combined with single-pixel detection to achieve spatial wavefront sensing, including a first lens, a second lens, a phased-array common-path phase-shifting interference structure, a third lens, a pinhole, and a detector. The first lens, the second lens, the third lens, the pinhole, and the detector are arranged along the optical axis direction. Among them, the first lens and the second lens form a 4f system, and its function is to flexibly adjust the actual measurement contact surface to the plane where the wavefront to be measured is located; the working surface of the phased array is placed on the confocal plane of the 4f system and the third lens; the pinhole is placed at the rear focal position of the third lens and is close to the detector. The phased-array common-path interference structure includes a half-wave plate, a phased array, and a polarizer. The half-wave plate and the polarizer are placed on both sides or the same side of the working surface of the phased array perpendicular to the optical axis along the optical axis direction. Adjust the directions of the polarizer and the half-wave plate so that the beam not modulated by the phased array and the modulated beam form common-path interference. The setting for forming common-path interference is selected from the following three methods: (i) Adjust the half-wave plate so that the polarization direction of the wavefront to be measured is the same as the polarization direction of the phased array, and adjust the direction of the polarizer to be the same as the direction of the half-wave plate, so that the wavefront reflected or transmitted and modulated by the pixel area of the phased array and the unmodulated wavefront directly reflected or transmitted through the pixel gap of the phased array pass through the polarizer to form common-path interference. (ii) Adjust the half-wave plate so that the polarization direction of the wavefront to be measured and the polarization direction of the phased array form an inclined angle, set the angle, and adjust the direction of the polarizer to be perpendicular to the direction of the half-wave plate, so that the wavefront reflected or transmitted and modulated by the pixel area of the phased array and the unmodulated wavefront reflected or transmitted through the pixel area of the phased array pass through the polarizer to form common-path interference. (iii) Adjust the half-wave plate so that the polarization direction of the wavefront to be measured and the polarization direction of the phased array form an inclined angle, and adjust the direction of the polarizer to be the same as the direction of the half-wave plate, so that the wavefront reflected or transmitted and modulated by the pixel area of the phased array, the unmodulated wavefront reflected or transmitted through the pixel area of the phased array, and the unmodulated wavefront directly reflected through the pixel gap of the phased array all pass through the polarizer to form common-path interference.

2. The device for realizing spatial wavefront sensing by phased array common-path interference single-pixel detection according to claim 1, wherein The phased array adopts a transmissive phased array or a reflective phased array. If the phased array is a transmissive phased array, the half-wave plate and the polarizer are placed on both sides of the working surface of the phased array perpendicular to the optical axis along the optical axis direction. The first lens, the second lens, the phased-array common-path interference structure, the third lens, the pinhole, and the detector are arranged in sequence along the optical axis direction. The first lens, the second lens, the phased-array common-path interference structure, the third lens, the pinhole, and the detector are all perpendicular to the optical axis. If the phased array is a reflective phased array, the half-wave plate and the polarizer are placed on the same side of the working surface of the phased array perpendicular to the optical axis along the optical axis direction. The first lens, the second lens, the phased-array common-path interference structure, the third lens, the pinhole, and the detector are arranged in sequence along the optical axis direction. The first lens, the second lens, the phased-array common-path interference structure, the third lens, the pinhole, and the detector are all perpendicular to the optical axis.

3. The device for realizing spatial wavefront sensing by phased array common-path interference single-pixel detection according to claim 2, wherein The phased array is used to carry the designed phase distribution, and plays an expected modulation role in the transmitted wavefront. The polarization direction is horizontal polarization or vertical polarization; The size of the pinhole r satisfies the relationship with the wavelength and diameter of the light beam incident on the third lens and the focal length of the third lens , where is the wavelength of the light beam, is the focal length of the third lens, is the diameter of the light beam.

4. A method for realizing spatial wavefront sensing by phased array common-path phase-shifting interference single-pixel detection, which is realized by using the device for realizing spatial wavefront sensing by phased array common-path interference single-pixel detection described in claim 1, and is characterized in that, The specific steps are as follows: Step 1: Relay the target spatial wavefront to the phased array working surface through the 4f system composed of the first lens and the second lens. Set the initial phase distribution of the phased array to the non-modulation mode. Determine the size of the pinhole according to the relationship that the wavelength and diameter of the light beam incident on the third lens and the focal length of the third lens satisfy , where r represents the size of the pinhole, is the wavelength of the light beam, is the focal length of the third lens, is the diameter of the light beam; Step 2: Adjust the directions of the polarizer and the half-wave plate so that the beam not modulated by the phased array and the modulated beam form a common-path interference; Step 3: Configure the initial parameters of the device for single-pixel detection of common-path interference of the phased array to achieve spatial wavefront sensing: the spatial wavefront imaging resolution M×N, the single-pixel imaging sampling rate φ, and the number of phase-shifting steps; Step 4: Load the modulation mode onto the phased array, and the detector collects the signal intensity; Phase-shift the φ×M×N modulation modes generated by single-pixel imaging respectively, and sequentially load them onto the phased array. At the same time, the detector collects the signal intensity values of the central point of the Fourier plane corresponding to each mode; Step 5: Reconstruct the target spatial wavefront: Obtain the complex coefficient spectrum of the target spatial wavefront based on the phase-shifting technique, and use the single-pixel reconstruction algorithm to restore the target spatial wavefront.

5. The method for realizing spatial wavefront sensing by phased array common-path phase-shifting interferometric single-pixel detection according to claim 4, characterized in that, In the second step, the setting for forming the common-path interference is selected from one of the following three methods: (i) Adjust the half-wave plate so that the polarization direction of the wavefront to be measured is the same as the polarization direction of the phased array, and adjust the polarizer direction to be the same as the half-wave plate direction, so that the wavefront reflected or transmitted and modulated by the phased array pixel area and the unmodulated wavefront directly reflected or transmitted through the phased array pixel gap pass through the polarizer to form a common-path interference; (ii) Adjust the half-wave plate so that the polarization direction of the wavefront to be measured forms an inclined angle with the polarization direction of the phased array, and adjust the polarizer direction to be perpendicular to the half-wave plate direction, so that the wavefront reflected or transmitted and modulated by the phased array pixel area and the unmodulated wavefront reflected or transmitted through the phased array pixel area pass through the polarizer to form a common-path interference; (iii) Adjust the half-wave plate so that the polarization direction of the wavefront to be measured forms an inclined angle with the polarization direction of the phased array, and adjust the polarizer direction to be the same as the half-wave plate direction, so that the wavefront reflected or transmitted and modulated by the phased array pixel area, the unmodulated wavefront reflected or transmitted through the phased array pixel area, and the unmodulated wavefront directly reflected through the phased array pixel gap all pass through the polarizer to form a common-path interference.

6. The method for realizing spatial wavefront sensing by phased array common-path phase-shifting interference single-pixel detection according to claim 4, characterized in that, The number of phase-shifting steps in the third step is: three-step phase shift or more than three-step phase shift.

7. The method for realizing spatial wavefront sensing by phased array common-path phase-shifting interferometric single-pixel detection according to claim 4, wherein The phased array is an indirect implementation of a pure phase modulator by a digital micromirror array, a ferroelectric liquid crystal spatial light modulator, and an amplitude liquid crystal spatial light modulator through the lee method or the superpixel method, or a pure phase liquid crystal spatial light modulator.

8. The method for realizing spatial wavefront sensing by phased array common-path phase-shifting interferometric single-pixel detection according to claim 4, characterized in that, The modulation modes include: Hadamard transform, discrete cosine transform, or Fourier transform.

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