Phase screen based array photonic orbital angular momentum beam quantum control system
The quantum control system for array photonic orbital angular momentum beams based on phase screens solves the problem of sub-beam overlap interference, generating independent array photonic orbital angular momentum beams suitable for discrete lattice illumination. It also allows for flexible control of the photonic orbital angular momentum order, changing the phase and intensity distribution of the beam.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HARBIN INST OF TECH
- Filing Date
- 2023-04-20
- Publication Date
- 2026-05-12
AI Technical Summary
In existing methods for generating array photonic orbital angular momentum beams, the sub-beams overlap and interfere with each other, which cannot meet the application requirements of discrete array illumination.
A quantum control system for array photonic orbital angular momentum beams based on a phase screen is adopted, which includes a laser, a beam shaping unit, a polarization control unit, and a quantum state control unit. Quantum state control is performed through a phase screen loaded by a spatial light modulator to ensure that adjacent unit vectors are perpendicular, thereby generating independent array photonic orbital angular momentum beams.
It achieves the independence of each sub-beam in the array photonic orbital angular momentum beam, is suitable for discrete lattice illumination, and can flexibly adjust the order of photonic orbital angular momentum to change the phase and intensity distribution of the beam.
Smart Images
Figure CN116430598B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to an anti-interference modulation technique for array photonic orbital angular momentum beams, which modulates independent sub-beams that do not overlap, and belongs to the field of quantum control technology. Background Technology
[0002] Photonic orbital angular momentum beams are optical fields with a helical phase structure, and they are currently widely used in optical communication, optical manipulation, and active laser detection.
[0003] Arrayed photonic orbital angular momentum beams can be used for array illumination, enabling two-dimensional array manipulation and cloud-resistant three-dimensional laser imaging. Existing methods for generating arrayed photonic orbital angular momentum beams include interferometry, spiral phase spatial filtering, and hollow multimode waveguide methods. The sub-beams generated by these methods overlap and interfere with each other, which is unfavorable for applications requiring discrete array illumination.
[0004] Therefore, to address the above shortcomings, it is necessary to provide an array of photonic orbital angular momentum beams, in which each sub-beam is independent and does not overlap. Summary of the Invention
[0005] To address the problem of overlapping interference between sub-beams in existing array photonic orbital angular momentum beams, this invention provides a quantum control system for array photonic orbital angular momentum beams based on a phase screen.
[0006] The quantum control system for arrayed photonic orbital angular momentum beams based on a phase screen according to the present invention includes a laser 1, a beam shaping unit, a polarization control unit, and a quantum state control unit;
[0007] The beam shaping unit is used to spatially filter and expand the laser beam generated by laser 1 to generate a parallel beam.
[0008] The polarization control unit is used to control the polarization of the parallel beam output by the beam shaping unit to generate a linearly polarized beam with a horizontal polarization state.
[0009] The quantum state manipulation unit is used to manipulate the orbital angular momentum of linearly polarized beams to obtain arrayed photonic orbital angular momentum beams, with each sub-beam in the array being independent.
[0010] The quantum state manipulation unit includes a spatial light modulator 7 and a computer 8. The quantum state manipulation process is as follows:
[0011] Computer 8 controls the phase screen loaded on the spatial light modulator 7 to regulate the quantum state of the incident laser, wherein the complex amplitude transmittance of the phase screen satisfies:
[0012]
[0013] Where T is the complex amplitude transmittance; rect(*) is the rectangular function;
[0014] Existence relation in Let 'a' represent any two adjacent unit vectors that are perpendicular to each other. In other words, on the phase screen loaded on the spatial light modulator, any two adjacent unit vectors are perpendicular to each other. The model;
[0015] x, y are the rectangular coordinates of each point on the phase screen, exp(*) is the exponential function e, i is the imaginary unit, l is the order of the photon orbital angular momentum of the phase screen, and φ is the polar coordinate azimuth of the photon orbital angular momentum light field of the phase screen.
[0016] c(n1,n2) are the summation coefficients, according to Find the values, where n1 is the row coefficient of the orbital angular momentum of the array photons and n2 is the column coefficient of the orbital angular momentum of the array photons, both of which are integers;
[0017] δ(*)δ is the delta function.
[0018] Preferably, the beam shaping unit includes a short focal length lens 2, a pinhole aperture 3, and a long focal length lens 4;
[0019] The rear focal plane of the short focal lens 2 coincides with the front focal plane of the long focal lens 4, and the pinhole stop 3 is located on the coincident focal plane; the laser beam is focused by the short focal lens 2 onto the light-transmitting aperture of the pinhole stop 3, and the transmitted light is compressed into a parallel beam by the long focal lens 4.
[0020] Preferably, the beam shaping unit expands the incident laser beam by a factor of f2 / f1. Here, f1 is the focal length of the short-focal-length lens, and f2 is the focal length of the long-focal-length lens. The expanded laser beam illuminates the spatial light modulator 7 as an approximately plane wave.
[0021] Preferably, the polarization control unit includes a linear polarizer 5 and a half-wave plate 6;
[0022] Linear polarizer 5 modulates the incident laser into linearly polarized light, and then half-wave plate 6 modulates the polarization direction of the incident linearly polarized light to the horizontal direction, generating linearly polarized light in a horizontal polarization state.
[0023] Preferably, the angle between the fast axis direction of the half-wave plate 6 and the polarization direction of the linear polarizer 5 is equal to the angle between the half-wave plate 6 and the horizontal direction of the fast axis direction.
[0024] Preferably, the spatial light modulator 7 is a phase controller based on the anisotropy of liquid crystal molecules, and the phase modulation direction is horizontal.
[0025] The beneficial effects of this invention are as follows: The system of this invention, through a phase screen loaded with a spatial light modulator, can control and obtain an array of photonic orbital angular momentum beams that are non-overlapping and independent of each other. This beam can be well applied to fields requiring discrete lattice illumination.
[0026] The beneficial effects of this invention are also reflected in the ability to flexibly adjust the photonic orbital angular momentum order of the array photonic orbital angular momentum beam, thereby changing the phase distribution and intensity distribution of the light cross section of the array photonic orbital angular momentum beam. Attached Figure Description
[0027] Figure 1 This is a block diagram of the quantum control system for array photonic orbital angular momentum beams based on a phase screen as described in this invention;
[0028] Figure 2 Schematic diagram of a phase screen for quantum control of an array of photon orbital angular momentum beams;
[0029] Figure 3 This is a diagram showing the intensity distribution of the cross-section of the array photon orbital angular momentum beam;
[0030] Figure 4 This is a phase distribution diagram of the optical cross section of the array photon orbital angular momentum beam.
[0031] 1. Laser, 2. Short focal length lens, 3. Pinhole aperture, 4. Long focal length lens, 5. Linear polarizer, 6. Half-wave plate, 7. Spatial light modulator, 8. Computer. Detailed Implementation
[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0033] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.
[0034] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.
[0035] Specific Implementation Method 1: The following is combined with... Figures 1 to 4 This embodiment describes a phase screen-based array photonic orbital angular momentum beam quantum control system, which includes a laser 1, a beam shaping unit, a polarization control unit, and a quantum state control unit.
[0036] The beam shaping unit is used to spatially filter and expand the laser beam generated by laser 1 to generate a parallel beam.
[0037] The beam shaping unit includes a short focal length lens 2, a pinhole aperture 3, and a long focal length lens 4;
[0038] The rear focal plane of the short focal lens 2 coincides with the front focal plane of the long focal lens 4, and the pinhole stop 3 is located on the coincident focal plane; the laser beam is focused by the short focal lens 2 onto the light-transmitting aperture of the pinhole stop 3, and the transmitted light contains components with lower spatial frequencies. The transmitted light is then compressed into a parallel beam by the long focal lens 4.
[0039] The beam shaping unit expands the incident laser beam by a factor of f2 / f1, where f1 is the focal length of the short-focal-length lens and f2 is the focal length of the long-focal-length lens. The expanded laser beam illuminates the spatial light modulator 7 as an approximately plane wave.
[0040] The laser beam generated by laser 1 is transformed into a near-parallel beam with a very small divergence angle and uniform amplitude and phase distribution of the electric field at the beam interface by the beam shaping unit.
[0041] The polarization control unit is used to control the polarization of the parallel beam output by the beam shaping unit to generate a linearly polarized beam with a horizontal polarization state.
[0042] The polarization control unit includes a linear polarizer 5 and a half-wave plate 6;
[0043] Linear polarizer 5 modulates the incident laser into linearly polarized light, and then half-wave plate 6 modulates the polarization direction of the incident linearly polarized light to the horizontal direction, generating linearly polarized light in a horizontal polarization state.
[0044] The angle between the fast axis direction of the half-wave plate 6 and the polarization direction of the linear polarizer 5 is equal to the angle between the half-wave plate 6 and the horizontal direction of the fast axis direction.
[0045] Since the spatial light modulator requires the incident beam to be polarized horizontally during quantum control, a polarization control unit is constructed using a combination of a linear polarizer 5 and a half-wave plate 6. After passing through the linear polarizer 5, the laser beam becomes a linearly polarized beam. To ensure energy utilization, the polarization direction of the linear polarizer is set to maximize the intensity of the transmitted light field. Because this direction forms an angle with the horizontal direction, the half-wave plate 6 is used to rotate the polarization direction of the incident linearly polarized light to the horizontal direction. When the angle between the fast axis of the half-wave plate 6 and the polarization direction of the linear polarizer 5 is equal to the angle between the fast axis of the half-wave plate 6 and the horizontal direction, the polarization direction of the incident linearly polarized light is rotated to the horizontal direction.
[0046] The quantum state manipulation unit is used to manipulate the orbital angular momentum of linearly polarized beams to obtain arrayed photonic orbital angular momentum beams, with each sub-beam in the array being independent.
[0047] The quantum state control unit includes a spatial light modulator 7 and a computer 8. The spatial light modulator 7 is a phase controller based on the anisotropy of liquid crystal molecules, and the phase control direction is horizontal.
[0048] The quantum state manipulation process is as follows:
[0049] Computer 8 controls the phase screen loaded on spatial light modulator 7 to regulate the quantum state of the incident laser. Spatial light modulator 7 controls the optical thickness of each pixel to form a phase screen. Figure 2 The quantum-controlled phase screen shown has a complex amplitude transmittance that satisfies:
[0050]
[0051] Where T is the complex amplitude transmittance; rect(*) is the rectangular function;
[0052] Existence relation in Let 'a' represent any two adjacent unit vectors that are perpendicular to each other. In other words, on the phase screen loaded on the spatial light modulator, any two adjacent unit vectors are perpendicular to each other. The model;
[0053] x, y are the rectangular coordinates of each point on the phase screen, exp(*) is the exponential function e, i is the imaginary unit, l is the order of the photon orbital angular momentum of the phase screen, and φ is the polar coordinate azimuth of the photon orbital angular momentum light field of the phase screen.
[0054] c(n1,n2) are the summation coefficients, according to Find the values, where n1 is the row coefficient of the orbital angular momentum of the array photons and n2 is the column coefficient of the orbital angular momentum of the array photons, both of which are integers;
[0055] δ(*)δ is the delta function.
[0056] The complex amplitude transmittance of the phase screen is a periodic arrangement of elementary functions on a lattice. Each elementary function constitutes a micro-spiral phase plate, which can modulate the incident beam into independent photon orbital angular momentum beams. As the diffraction distance of the light field increases, the array beam gradually diverges, and the spacing between the sub-beams gradually increases, causing them to separate from each other.
[0057] The following is a specific example:
[0058] A laser beam with a spot radius of about 2 mm is generated using a laser with a wavelength of 532 nm. After being focused by a short focal length lens with a focal length of 1 cm, the high spatial frequency components are filtered out by a small aperture with a light-passing diameter of 10 μm. Then, a long focal length lens with a focal length of 10 cm is used to shrink the beam to obtain a near-parallel beam with a spot radius of about 2 cm.
[0059] After filtering and beam expansion, the laser beam becomes a linearly polarized beam after passing through a polarizer. To ensure energy utilization, the polarizer's polarization direction is set to maximize the intensity of the transmitted light field. Then, a half-wave plate is used to rotate the polarization direction of the incident linearly polarized light to the horizontal direction. The angle between the fast axis of the half-wave plate and the polarizer's polarization direction is equal to the angle between the fast axis of the half-wave plate and the horizontal direction.
[0060] Loading such as... onto a spatial light modulator controlled by a computer Figure 2 The quantum-controlled phase screen shown has a value of a = 320 μm, which occupies 40 pixels of the spatial light modulator; and a value of l = 1, which generates the first-order array photon orbital angular momentum.
[0061] A nearly parallel beam of light with a horizontal polarization direction illuminates a spatial light modulator loaded with a quantum-controlled phase screen, and the emitted light is modulated to have a polarization direction such as... Figure 3 The light intensity distribution shown and as Figure 4 The phase distribution of the array photon orbital angular momentum beam is shown.
[0062] from Figure 3 It can be seen that each sub-beam is independent of the others and there is no overlap, which overcomes the defect of mutual interference between sub-beams in the existing method.
[0063] The beneficial effects of this invention are also reflected in its ability to flexibly control the photon orbital angular momentum order of the array photon orbital angular momentum beam. Figure 2 The expression for each photon orbital angular momentum modulation unit is lφ. Figure 3 The radius of the light ring in each unit of the light field intensity distribution increases with the order and decreases with the order. Figure 4 The phase pattern expression for each unit in the phase distribution is also lφ, and the corresponding phase distribution changes with the order.
[0064] While the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.
Claims
1. A quantum control system for array photonic orbital angular momentum beams based on a phase screen, characterized in that, It includes a laser (1), a beam shaping unit, a polarization control unit, and a quantum state control unit; The beam shaping unit is used to spatially filter and expand the laser beam generated by the laser (1) to generate a parallel beam. The polarization control unit is used to control the polarization of the parallel beam output by the beam shaping unit to generate a linearly polarized beam with a horizontal polarization state. The quantum state manipulation unit is used to manipulate the orbital angular momentum of linearly polarized beams to obtain arrayed photonic orbital angular momentum beams, with each sub-beam in the array being independent. The quantum state control unit includes a spatial light modulator (7) and a computer (8). The quantum state control process is as follows: The computer (8) controls the phase screen loaded on the spatial light modulator (7) to regulate the quantum state of the incident laser, wherein the complex amplitude transmittance of the phase screen satisfies: Where T is the complex amplitude transmittance; rect(*) is the rectangular function; Existence relation in Let 'a' represent any two adjacent unit vectors that are perpendicular to each other. In other words, any two adjacent unit vectors on the phase screen loaded on the spatial light modulator are perpendicular to each other. The model; x, y are the rectangular coordinates of each point on the phase screen, exp(*) is the exponential function e, i is the imaginary unit, l is the order of the photon orbital angular momentum of the phase screen, and φ is the polar coordinate azimuth of the photon orbital angular momentum light field of the phase screen. c(n1,n2) is the summation coefficient, according to Find the values, where n1 is the row coefficient of the orbital angular momentum of the array photons and n2 is the column coefficient of the orbital angular momentum of the array photons, both of which are integers; δ(*)δ is the delta function.
2. The quantum control system for array photonic orbital angular momentum beams based on a phase screen according to claim 1, characterized in that, The beam shaping unit includes a short focal length lens (2), a pinhole aperture (3), and a long focal length lens (4); The rear focal plane of the short focal lens (2) coincides with the front focal plane of the long focal lens (4), and the pinhole stop (3) is located on the coincident focal plane; the laser beam is focused by the short focal lens (2) onto the aperture of the pinhole stop (3), and the transmitted light is compressed into a parallel beam by the long focal lens (4).
3. The quantum control system for array photonic orbital angular momentum beams based on a phase screen according to claim 2, characterized in that, The beam shaping unit expands the incident laser beam by a factor of f2 / f1; where f1 is the focal length of the short focal length lens and f2 is the focal length of the long focal length lens, and the expanded laser beam illuminates the spatial light modulator (7) as an approximate plane wave.
4. The quantum control system for array photonic orbital angular momentum beams based on a phase screen according to claim 1, characterized in that, The polarization control unit includes a linear polarizer (5) and a half-wave plate (6); The linear polarizer (5) modulates the incident laser into linearly polarized light, and then the half-wave plate (6) modulates the polarization direction of the incident linearly polarized light into the horizontal direction, generating linearly polarized light in a horizontal polarization state.
5. The quantum control system for array photonic orbital angular momentum beams based on a phase screen according to claim 4, characterized in that, The angle between the fast axis direction of the half-wave plate (6) and the polarization direction of the linear polarizer (5) is equal to the angle between the half-wave plate (6) and the horizontal direction of the fast axis.
6. The quantum control system for array photonic orbital angular momentum beams based on a phase screen according to claim 1, characterized in that, The spatial light modulator (7) is a phase controller based on the anisotropy of liquid crystal molecules, and the phase modulation direction is horizontal.