Method and device for making optical moiré superlattice

Abstract

The present invention discloses a method and device for manufacturing an optical moiré superlattice. The superlattice structure is designed by using a bidirectional coaxial wavefront interference method of two incoherent light beams. A device is constructed by using components such as solid lasers, beam splitters, reflectors, and wavefront templates to realize the superposition of bidirectional vertically polarized light beam interference fields to manufacture the optical moiré superlattice structure. The method has the advantages of a simple manufacturing method and easy adjustment of the device.

Description

Technical Field

[0001] The invention belongs to the field of optical technology, and in particular relates to a method and a device for manufacturing an optical moiré superlattice. Background Art

[0002] Optical moiré superlattice is formed by rotating two or more sublattices with the same periodic structure at a certain angle and superimposing them. It has new properties that a single sublattice periodic structure does not have, such as rich physical flat bands, strong field localization and topological properties, etc. It has opened up a new research field for the spatial regulation of light fields and truly realized the new vision of one plus one being greater than two. The rich physical flat bands have greatly expanded its applications in slow light waveguides, low-threshold nanolasers, high-efficiency solar cells, quantum nonlinearity, etc.

[0003] At present, the research on optical moiré superlattices is still in its early stages, with most of the research focusing on theoretical design and characteristics, and relatively few related production methods and devices. Summary of the invention

[0004] In view of this, the present invention provides a method and device for manufacturing an optical moiré superlattice.

[0005] The specific plan is as follows:

[0006] The method for making an optical moiré superlattice comprises the following steps:

[0007] Step 1: Generate linearly polarized light and expand the linearly polarized light;

[0008] Step 2: Split the expanded linearly polarized light into a first light beam and a second light beam, and deflect the first light beam into a first horizontal light beam, and deflect the second light beam into a second horizontal light beam, wherein the first horizontal light beam and the second horizontal light beam are coaxial and in opposite directions;

[0009] Step 3: Split the first horizontal light beam into a plurality of parallel light beams I, and split the second horizontal light beam into a plurality of parallel light beams II, wherein the plurality of parallel light beams I and the plurality of light beams II are coaxial and in opposite directions;

[0010] Step 4: With the central axis of the multiple parallel light beams I and the multiple parallel light beams II as the center, the multiple parallel light beams I are rotated by an arbitrary angle α along the circumference of the axis, and converged together with the multiple parallel light beams II onto two opposite sides of the photosensitive medium PSM, thereby obtaining an optical moiré superlattice structure;

[0011] Alternatively, after rotating a plurality of parallel light beams II by an arbitrary angle α along the circumference of the axis, the plurality of parallel light beams I converge together on two opposite sides of the photosensitive medium PSM, thereby obtaining an optical moiré superlattice structure.

[0012] The linearly polarized light is generated by a laser, and the optical path difference between the first light beam and the second light beam is greater than the coherence length of the laser.

[0013] Multiple parallel light beams I converge symmetrically on the photosensitive medium PSM to obtain a first sublattice structure, and multiple parallel light beams II converge symmetrically on the photosensitive medium PSM to obtain a second sublattice structure. The photosensitive medium PSM simultaneously records the first sublattice structure and the second sublattice structure to obtain an optical moiré superlattice structure.

[0014] An optical moiré superlattice manufacturing device includes a solid laser, a beam expansion system, a beam splitter, a beam deflection system, a beam splitting and converging system, and a photosensitive medium PSM, wherein:

[0015] A beam expansion system is fixed on the optical path of the solid laser, and a beam splitter is fixed on the optical path of the beam expansion system, and the beam splitter splits the linearly polarized light after beam expansion into a first beam and a second beam;

[0016] A beam deflection system is fixed on the optical path of the first light beam and the optical path of the second light beam, and the beam deflection system deflects the first light beam into a first horizontal light beam and the beam deflection system deflects the second light beam into a second horizontal light beam;

[0017] A beam splitting and converging system is fixed on the optical path of the first horizontal light beam and the optical path of the second horizontal light beam. The first horizontal light beam is converged onto the photosensitive medium PSM through the beam splitting and converging system, and the second horizontal light beam is converged onto the photosensitive medium PSM through the beam splitting and converging system.

[0018] The beam splitting and converging system comprises a first beam splitting and converging system and a second beam splitting and converging system, wherein the first beam splitting and converging system and the second beam splitting and converging system are symmetrically fixed on opposite sides of the photosensitive medium PSM.

[0019] The first beam splitting and converging system includes a first wave splitting panel and a first lens, which are fixed on one side of the photosensitive medium PSM in sequence, and the second beam splitting and converging system includes a second wave splitting panel and a second lens, which are fixed on the other side of the photosensitive medium PSM in sequence, the first lens and the second lens are both convex lenses, the first wave splitting panel and the second wave splitting panel are circular panels, and the circular panels are fixed with rotationally symmetrical light-through holes.

[0020] The beam deflection system includes a first reflector, a second reflector and a third reflector, wherein the first reflector is fixed between the beam splitter and the first wave splitting panel, the second reflector and the third reflector are fixed between the beam splitter and the second wave splitting panel in sequence, the second reflector and the third reflector are perpendicular to each other, and the first reflector, the second reflector and the third reflector all deflect the light beam by 45°.

[0021] The beam splitter and the optical path of the beam expansion system are fixed at an angle of 45°.

[0022] The beam expansion system is a Galilean telescope beam expansion system.

[0023] The invention discloses a method and device for manufacturing an optical moiré superlattice. The method comprises the following steps: expanding a laser beam and then splitting the laser beam into two incoherent light beams, namely a first light beam and a second light beam. The first light beam is then deflected and split to generate a plurality of parallel light beams I. The second light beam is deflected and split to generate a plurality of parallel light beams II. The plurality of parallel light beams I converge and coaxially interfere. The plurality of parallel light beams II converge and coaxially interfere. A photosensitive medium PSM is used for interference recording to obtain an optical moiré superlattice structure. The optical moiré superlattice structure is manufactured by using an interference method of two incoherent light bidirectional split wave surfaces. Different types of moiré superlattice structures can be quickly designed and manufactured by replacing different split wave panels. The manufacturing method is simple and the device is easy to adjust. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the structure of the optical moiré superlattice production device.

[0025] Figure 2 It is a structural schematic diagram of a four-hole wave-splitting panel.

[0026] Figure 3 It is a square moiré superlattice structure with four-hole wave-splitting panels rotated at different angles.

[0027] Figure 4 It is a structural diagram of a three-hole wave splitting panel.

[0028] Figure 5 It is a hexagonal moiré superlattice structure with three-hole wave-dividing panels rotated at different angles.

[0029] Figure 6 It is a structural schematic diagram of a two-hole wave splitting panel.

[0030] Figure 7 It is a moiré superlattice structure with two-hole wave-dividing panels rotated at different angles. DETAILED DESCRIPTION

[0031] The following will be combined with the accompanying drawings in the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the implementation of the present invention, not all of the implementations. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] The method for making an optical moiré superlattice comprises the following steps:

[0033] Step 1: Generate linearly polarized light and expand the linearly polarized light;

[0034] Step 2: Split the expanded linearly polarized light into a first light beam and a second light beam, and deflect the first light beam into a first horizontal light beam, and deflect the second light beam into a second horizontal light beam, wherein the first horizontal light beam and the second horizontal light beam are coaxial and in opposite directions;

[0035] Step 3: The first splitter panel 7 splits the first horizontal light beam 4 into a plurality of rotationally symmetrical parallel light beams I, and the second splitter panel 11 splits the second horizontal light beam 5 into a plurality of rotationally symmetrical parallel light beams II. The second splitter panel 11 has the same structure as the first splitter panel 7 and is rotated relative to the first splitter panel 7 along the central axis by an angle a. The plurality of parallel light beams I and the plurality of parallel light beams II are coaxially opposite to each other and have a relative rotation angle a.

[0036] Step 4: Multiple parallel light beams I converge onto the photosensitive medium PSM to form a first sublattice structure, and multiple parallel light beams II converge onto the other side of the photosensitive medium PSM to form a second sublattice structure. The two sublattice structures are superimposed to obtain an optical moiré superlattice structure.

[0037] The linearly polarized light is generated by a laser, and the optical path difference between the first light beam and the second light beam is greater than the coherence length of the laser, so that the first light beam and the second light beam are incoherent lights.

[0038] Multiple parallel light beams I converge symmetrically on the photosensitive medium PSM to obtain a first sublattice structure, and multiple parallel light beams II converge symmetrically on the photosensitive medium PSM to obtain a second sublattice structure. The photosensitive medium PSM simultaneously records the first sublattice structure and the second sublattice structure to obtain an optical moiré superlattice structure.

[0039] like Figure 1 As shown, an optical moiré superlattice manufacturing device is characterized by comprising a solid laser 1, a beam expansion system 2, a beam splitter 3, a beam deflection system, a beam splitting and converging system and a photosensitive medium PSM9, wherein:

[0040] A beam expansion system 2 is fixed on the optical path of the solid laser 1, and a beam splitter 3 is fixed on the optical path of the beam expansion system 2. The beam splitter 3 splits the expanded linearly polarized light into a first beam 4 and a second beam 5;

[0041] A beam deflection system is fixed on the optical path of the first light beam 4 and the optical path of the second light beam 5, and the beam deflection system deflects the first light beam 4 into a first horizontal light beam, and the beam deflection system deflects the second light beam 5 into a second horizontal light beam;

[0042] A beam splitting and converging system is fixed on the optical path of the first horizontal light beam and the optical path of the second horizontal light beam. The first horizontal light beam is converged onto the photosensitive medium PSM9 through the beam splitting and converging system, and the second horizontal light beam is converged onto the photosensitive medium PSM9 through the beam splitting and converging system.

[0043] The beam splitting and converging system comprises a first beam splitting and converging system and a second beam splitting and converging system, wherein the first beam splitting and converging system and the second beam splitting and converging system are symmetrically fixed on two opposite sides of the photosensitive medium PSM9.

[0044] The first beam splitting and converging system includes a first wave splitting panel 7 and a first lens 8, which are fixed on one side of the photosensitive medium PSM9 in sequence. The second beam splitting and converging system includes a second wave splitting panel 11 and a second lens 10, which are fixed on the other side of the photosensitive medium PSM9 in sequence. The first lens 8 and the second lens 10 are both convex lenses. The first wave splitting panel 7 and the second wave splitting panel 11 are circular panels, and a rotationally symmetrical light-through hole 14 is fixed on the circular panel. The rest of the circular panel is opaque, and the light beam can pass through the light-through hole 14. The first wave splitting panel 7 and the second wave splitting panel 11 have exactly the same structure.

[0045] The beam deflection system includes a first reflector 6, a second reflector 12 and a third reflector 13, wherein the first reflector 6 is fixed between the beam splitter 3 and the first wave splitter panel 7, the second reflector 12 and the third reflector 13 are fixed between the beam splitter 3 and the second wave splitter panel 11 in sequence, the second reflector 12 and the third reflector 13 are perpendicular to each other, and the first reflector 6, the second reflector 12 and the third reflector 13 all deflect the light beam by 45°.

[0046] The beam splitter 3 and the optical path of the beam expansion system 2 are fixed at an angle of 45°.

[0047] The beam expansion system 2 is a Galilean telescope beam expansion system.

[0048] The specific working process of the optical moiré superlattice device is as follows:

[0049] like Figure 1 As shown, a solid laser 1 (Solid Laser) emits linearly polarized light, which is expanded by a beam expansion system composed of two lenses and then split into a first light beam 4 and a second light beam 5 by a beam splitter 3 (BS).

[0050] The first light beam 4 is divided into a plurality of parallel light beams I by the first reflector 6 and the first wave splitter plate 7. The number of the parallel light beams I is determined by the number of the light holes 14 on the first wave splitter plate 7. The first lens 8 makes the plurality of parallel light beams I incident on the photosensitive medium PSM9 in an umbrella-shaped symmetrical structure to obtain a first sub-lattice structure.

[0051] The second light beam 5 is incident on the second wave splitting panel 11 via the third reflector 13 and the second reflector 12. The second wave splitting panel 11 splits the second light beam 5 into a plurality of parallel light beams II. In the present embodiment, the first wave splitting panel 8 and the second wave splitting panel 11 are coaxial and collinear, and the second wave splitting panel 11 is rotated around the central axis by an angle a relative to the first wave splitting panel 8. The second lens 10 converges the plurality of parallel light beams II coaxially and symmetrically onto the photosensitive medium PSM9 to obtain a second sublattice structure.

[0052] When the optical path difference between the first light beam 4 and the second light beam 5 is greater than the coherence length of the solid laser 1, the photosensitive medium PSM9 records the first sublattice structure and the second sublattice structure simultaneously, and an optical moiré superlattice structure can be obtained.

[0053] The structures of the first wave splitter panel 7 and the second wave splitter panel 11 can be replaced. Replacing the first wave splitter panel 7 and the second wave splitter panel 11 with different structures can produce different optical moiré superlattice structures. In this embodiment, the generation of optical moiré superlattice structures by four-hole wave splitter panels, three-hole wave splitter panels and two-hole wave splitter panels is described in detail.

[0054] like Figure 2 As shown, if the first wave splitting panel 7 and the second wave splitting panel 11 are both four-hole wave splitting panels, the first wave splitting panel 7 and the second wave splitting panel 11 share a central axis, and the axial rotation angle of the second wave splitting panel 11 relative to the first wave splitting panel 7 along the central axis is α;

[0055] When the light holes 14 on the first wave splitting plate 7 and the light holes 14 on the second wave splitting plate 11 are both four-hole rotationally symmetrical structures, the light intensity distribution formula of the generated moiré superlattice structure is:

[0056] (1)

[0057] in,

[0058] I is the light intensity distribution, M ( x,y )、 M ( x 1 ，y 1) is the light intensity distribution of the first sub-lattice structure and the second sub-lattice structure, x,y are the coordinates of the interference of the first light beam 4 on the photosensitive medium PSM9,x 1 ,y 1 is the coordinate of the interference of the second light beam 5 on the photosensitive medium PSM9, that is, x,y Coordinates rotated by angle a around the origin

[0059] (2)

[0060] in,

[0061] p It is the first wave after being split by 7 waves by the first wave splitting panel. p beam of light;

[0062] q is the first wave after being split by the second splitting panel 11 q Beam, for the four-hole wave splitting panel, p and q All are integers from 1 to 4;

[0063] Ep is the light field, Eq * is a conjugate light field;

[0064] A p It is p The amplitude of the beam, k p It is p The wave vector of the beam;

[0065] A q It is q The amplitude of the beam, k q It is q The wave vector of the beam;

[0066] The calculation formula for the wave vectors of the four beams of light generated by the four-hole wave splitting panel is:

[0067] (3)

[0068] Wherein, θ is the angle between the light beam and the central axis after passing through the first lens 8 or the second lens 11, and is also the incident angle of the light beam on the photosensitive medium PSM9.

[0069] coordinate( x 1 ,y 1) and ( x , y ) is,

[0070] (4)

[0071] Wherein, α is the axial rotation angle of the second wave splitting plate 11 relative to the first wave splitting plate 7 along the central axis;

[0072] In this embodiment, if the assignment A p =A q =1, q= 20 o , and a takes different angle values, such as 5°, 10°, 22.5° and 45°. Substituting into formulas (1) to (4) we can obtain the first sublattice structure, the second sublattice structure and the moiré superlattice structure when rotating at different angles a, as shown in Figure 3 shown.

[0073] Figure 3 (a) is the first sublattice structure;

[0074] Figure 3 (b) is the second sublattice structure when a=10°;

[0075] Figure 3 (c) is the optical moiré superlattice structure when a=10°;

[0076] Figure 3 (d) is the optical moiré superlattice structure when a=5°;

[0077] Figure 3 (e) is the optical moiré superlattice structure when α=22.5°;

[0078] Figure 3 (f) is the optical moiré superlattice structure when α=45°;

[0079] from Figure 3 Different optical lattice structures can be seen in the figure: different Bravis lattices, double-periodic square lattice structures of different sizes Figure 3 (c), (d), (e) and the eight-fold rotationally symmetric quasicrystal structure (f).

[0080] Change the structure of the split wave panel to a three-hole split wave panel, such as Figure 4 As shown, the wave vector calculation formula of the three beams of light generated by the three-hole wave splitting panel is

[0081] (5)

[0082] For three-hole wave splitting panel, p、q 1~3, same value A p =A q =1, q= 20 o, a takes four different angle values ​​of 5°, 10°, 15° and 30°; from formula (1), formula (2), formula (4) and formula (5), the first sublattice structure, the second sublattice structure and the moiré superlattice structure when rotating at different angles a can be obtained, as shown in Figure 5 shown.

[0083] Figure 5 (a) is the first sublattice structure;

[0084] Figure 5 (b) is the second sublattice structure when a=10°;

[0085] Figure 5 (c) is the optical moiré superlattice structure when a=10°;

[0086] Figure 5 (d) is the optical moiré superlattice structure when a=5°;

[0087] Figure 5 (e) is the optical moiré superlattice structure when α=15°;

[0088] Figure 5 (f) is the optical moiré superlattice structure when α=30°;

[0089] from Figure 5 In the figure, we can see double-periodic hexagonal lattice structures of different sizes. Figure 5 (c), (d), (e) and the twelve-fold rotationally symmetric quasicrystal structure (f).

[0090] Change the structure of the wave splitting panel to a two-hole wave splitting panel, such as Figure 6 As shown, the wave vector calculation formula of the two beams of light generated by the two-hole wave splitting panel is

[0091] (6)

[0092] For the two-hole wave splitting panel, p、q 1~2, same value A p =A q =1, q= 20 o , a takes four different angle values ​​of 5°, 10°, 22.5° and 90°; from formula (1), formula (2), formula (4) and formula (6), the first sublattice structure, the second sublattice structure and the moiré superlattice structure when rotating at different angles a can be obtained, as shown in Figure 7 shown.

[0093] Figure 7 (a) is the first sublattice structure;

[0094] Figure 7 (b) is the second sublattice structure when a=10°;

[0095] Figure 7 (c) is the optical moiré superlattice structure when a=10°;

[0096] Figure 7 (d) is the optical moiré superlattice structure when a=5°;

[0097] Figure 7 (e) is the optical moiré superlattice structure when α=22.5°;

[0098] Figure 7 (f) is the optical moiré superlattice structure when α=90°;

[0099] from Figure 7 In the figure, we can see double-periodic moiré fringe structures of different sizes. Figure 7 (c), (d), (e) and square lattice structure (f).

[0100] The present invention realizes two incoherent lights by adjusting the optical path difference of the two light beams to be greater than the coherence length of the laser, and designs a superlattice structure of the two incoherent lights through a bidirectional coaxial wavefront interference method, including using a symmetrical four-hole wavefront template to generate a square lattice structure of four-beam interference and a three-hole template to generate a triangular lattice structure of three-beam interference, and designing different two-dimensional moiré superlattice structures by rotating the relative angle of the bidirectional wavefront template; and using the same double-hole wavefront template to rotate to generate a two-dimensional moiré lattice structure by bidirectional interference, and using a solid laser, a beam splitter, a reflector, a wavefront template lens and a photosensitive medium PSM device to build a device to realize bidirectional interference field superposition to produce an optical moiré superlattice structure. The production method is simple and the device is easy to adjust.

[0101] The technical means disclosed in the scheme of the present invention are not limited to the technical means disclosed in the above-mentioned implementation mode, but also include technical schemes composed of any combination of the above-mentioned technical features. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications are also regarded as the protection scope of the present invention.

Claims

1. A method for fabricating an optical moiré superlattice, characterized in that: The invention comprises a solid laser (1), a beam expansion system (2), a beam splitter (3), a beam deflection system, a beam splitting and converging system and a photosensitive medium PSM (9), wherein: A beam expansion system (2) is fixed on the optical path of the solid laser (1), and a beam splitter (3) is fixed on the optical path of the beam expansion system (2), and the beam splitter (3) splits the expanded linearly polarized light into a first light beam (4) and a second light beam (5); A beam deflection system is fixed on the optical path of the first light beam (4) and the optical path of the second light beam (5), the beam deflection system deflects the first light beam (4) into a first horizontal light beam, and the beam deflection system deflects the second light beam (5) into a second horizontal light beam; A beam splitting and converging system is fixed on the optical path of the first horizontal light beam and the optical path of the second horizontal light beam, the first horizontal light beam is converged onto the photosensitive medium PSM (9) through the beam splitting and converging system, and the second horizontal light beam is converged onto the photosensitive medium PSM (9) through the beam splitting and converging system; The method comprises the following steps, Step 1: Generate linearly polarized light and expand the linearly polarized light; Step 2: Split the expanded linearly polarized light into a first light beam and a second light beam, and deflect the first light beam into a first horizontal light beam, and deflect the second light beam into a second horizontal light beam, wherein the first horizontal light beam and the second horizontal light beam are coaxial and in opposite directions; Step 3: Split the first horizontal light beam into a plurality of parallel light beams I, and split the second horizontal light beam into a plurality of parallel light beams II, wherein the plurality of parallel light beams I and the plurality of light beams II are coaxial and in opposite directions; Step 4: With the central axis of the multiple parallel light beams I and the multiple parallel light beams II as the center, the multiple parallel light beams I are rotated by an arbitrary angle α along the circumference of the axis, and converged together with the multiple parallel light beams II onto two opposite sides of the photosensitive medium PSM, thereby obtaining an optical moiré superlattice structure; Alternatively, after rotating a plurality of parallel light beams II by an arbitrary angle α along the circumference of the axis, the plurality of parallel light beams I converge together on two opposite sides of the photosensitive medium PSM, thereby obtaining an optical moiré superlattice structure.

2. The method for fabricating an optical moiré superlattice according to claim 1, characterized in that: The linearly polarized light is generated by a laser, and the optical path difference between the first light beam and the second light beam is greater than the coherence length of the laser.

3. The method for fabricating an optical moiré superlattice according to claim 1, characterized in that: Multiple parallel light beams I converge symmetrically on the photosensitive medium PSM to obtain a first sublattice structure, and multiple parallel light beams II converge symmetrically on the photosensitive medium PSM to obtain a second sublattice structure. The photosensitive medium PSM simultaneously records the first sublattice structure and the second sublattice structure to obtain an optical moiré superlattice structure.

4. An optical moiré superlattice fabrication device according to the method of claim 1, characterized in that: The beam splitting and converging system comprises a first beam splitting and converging system and a second beam splitting and converging system, wherein the first beam splitting and converging system and the second beam splitting and converging system are symmetrically fixed on two opposite sides of the photosensitive medium PSM (9).

5. The optical moiré superlattice fabrication device according to claim 4, characterized in that: The first beam splitting and converging system comprises a first wave splitting panel (7) and a first lens (8), the first wave splitting panel (7) and the first lens (8) being fixed in sequence on one side of a photosensitive medium PSM (9), and the second beam splitting and converging system comprises a second wave splitting panel (11) and a second lens (10), the second wave splitting panel (11) and the second lens (10) being fixed in sequence on the other side of the photosensitive medium PSM (9), the first lens (8) and the second lens (10) being both convex lenses, the first wave splitting panel (7) and the second wave splitting panel (11) being circular panels, and the circular panels being fixed with rotationally symmetrical light holes (14).

6. The optical moiré superlattice fabrication device according to claim 5, characterized in that: The light beam deflection system comprises a first reflector (6), a second reflector (12) and a third reflector (13); the first reflector (6) is fixed between the beam splitter (3) and the first wave splitting panel (7); the second reflector (12) and the third reflector (13) are fixed in sequence between the beam splitter (3) and the second wave splitting panel (11); the second reflector (12) and the third reflector (13) are perpendicular to each other; and the first reflector (6), the second reflector (12) and the third reflector (13) all deflect the light beam by 45 degrees.

7. The optical moiré superlattice fabrication device according to claim 4, characterized in that: The beam splitter (3) and the optical path of the beam expansion system (2) are fixed at an angle of 45°.

8. The optical moiré superlattice fabrication device according to claim 4, characterized in that: The beam expansion system (2) is a Galilean telescope beam expansion system.

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