Selectively excited half-dislocation double-optical microcavity

Abstract

The invention discloses a selectively excited half-dislocation double-optical microcavity which comprises a ferrite cylinder half-dislocation array, a parallel plate waveguide and an electromagnetic absorption material. The ferrite cylinder semi-dislocation array forming method comprises the following steps: firstly, arranging ferrite cylinders according to a rectangular dot matrix to form a photonic crystal, wherein the photonic crystal is divided into an upper sub-dot matrix and a lower sub-dot matrix; embedding a half row of ferrite cylinders along the center line of the upper sub-dot matrix, and finally adjusting the positions of the cylinders at the interface of the upper sub-dot matrix and the lower sub-dot matrix to obtain two half-dislocation microcavities. The semi-dislocation array is placed between the parallel plate waveguides; the four boundaries are covered with electromagnetic absorbing materials; the direction of the external magnetic field is perpendicular to the array plane. According to the selectively excited double optical microcavity, the time reversal symmetry is broken through an external magnetic field, so that selective excitation in a mirror symmetry structure is realized. The half-dislocation double-optical microcavity selective excitation mechanism provided by the invention has the advantages of simple principle, compact structure, high excitation ratio, small electromagnetic loss, strong anti-interference performance and the like.

Description

Technical Field

[0001] The invention relates to the field of photonic crystals and photonic devices, and in particular to a selectively excited half-dislocation dual optical microcavity. Background Art

[0002] Optical microcavities have been widely studied because of their ability to gather energy through resonance in a very small volume. They play an irreplaceable role in light sensing and light-matter interaction and are widely used in optical devices such as microlasers, photon frequency combs, and integrated photonic devices. Optical microcavities mainly include Fabry-Perot microcavities, whispering gallery microcavities, and photonic crystal microcavities, among which photonic crystal microcavities are mainly known for their high Q value and low loss. In general, traditional photonic crystal microcavities rely on artificial point defects. However, such point defect microcavities are very fragile, and slight manufacturing errors or misalignments can lead to severe mode frequency drift and Q value drop. In addition, due to mirror symmetry, if there are multiple identical microcavities in a system, all microcavities will be excited at the same frequency at the same time, limiting the scope of application. Summary of the invention

[0003] Purpose of the invention: In view of the shortcomings of the prior art, the purpose of the present invention is to provide a half-dislocation dual optical microcavity that can be selectively excited. Based on a rectangular lattice of ferrite cylinders, two half-dislocation optical microcavities are constructed by embedding half a row of ferrite cylinders, and the time reversal symmetry is broken by an external magnetic field to achieve selective excitation. The invention has the advantages of simple structure, high excitation ratio, strong anti-interference, etc.

[0004] Technical solution: To achieve the above-mentioned invention purpose, the present invention provides a selectively excited half-dislocation dual optical microcavity, comprising a ferrite cylinder half-dislocation array, a parallel plate waveguide and an electromagnetic absorption material, wherein the ferrite cylinder half-dislocation array is formed by the following method: firstly, ferrite cylinders are arranged in a rectangular lattice to form a photonic crystal, and the photonic crystal is divided into an upper and a lower sub-lattice; then, a half-row of ferrite cylinders are embedded along the center line of the upper sub-lattice, and the embedded half-row of ferrite cylinders squeezes the ferrite cylinders on both sides of the center line of the upper sub-lattice, causing the cylinders on both sides to move to the left and right directions respectively; at the same time, the ferrite cylinders at the junction of the upper sub-lattice and the lower sub-lattice produce lattice dislocations due to squeezing; the positions of the ferrite cylinders at the junction are adjusted according to the squeezing deformation to obtain a pair of half-dislocation microcavities located at the junction of the upper and lower sub-lattices; the half-dislocation array formed by the upper and lower sub-lattices is placed between the parallel plate waveguides; the four boundaries are covered with electromagnetic absorption materials; the direction of the external magnetic field is perpendicular to the array plane.

[0005] Preferably, the photonic crystal formed by arranging the ferrite columns in a rectangular lattice comprises at least 22 rows of ferrite columns.

[0006] Preferably, the ferrite cylindrical half-dislocation array satisfies mirror symmetry, and the lattice constant in the length direction of the rectangular lattice arrangement is twice the lattice constant in the width direction.

[0007] Preferably, the two half-dislocation microcavities are respectively located on the left and right sides of the center line, and by embedding half a row of ferrite cylinders into the upper sub-lattice along the center line, the additionally embedded ferrite cylinders cause extrusion deformation to the ferrite cylinders on both sides of the center line of the upper sub-lattice, and also cause lattice dislocation at the interface between the upper and lower sub-lattices, forming two half-dislocation microcavities with openings facing upward.

[0008] Preferably, the ferrite cylinders in the ferrite cylinder array are yttrium iron garnet (YIG) cylinders.

[0009] Preferably, the two half-dislocation microcavities in the ferrite cylindrical half-dislocation array are located on both sides of the array centerline, and the two half-dislocation microcavities are mirror-symmetrical along the array centerline.

[0010] Preferably, the electromagnetic excitation source is placed above or below the middle row of ferrite cylinders.

[0011] Preferably, the electromagnetic excitation source is a point source placed at the center of the line connecting the two half-dislocation optical microcavities.

[0012] Preferably, the detection source is placed at the geometric center of the half-dislocation optical microcavity.

[0013] Preferably, a single optical microcavity is selectively excited by adjusting the direction of the magnetic field.

[0014] Working principle: The selective excitation of the half-dislocation dual optical microcavity proposed in the present invention first constructs a ferrite cylinder array based on a rectangular lattice, and constructs a half-dislocation dual cavity structure by embedding a half-row of ferrite cylinders, thereby obtaining a pair of optical microcavities with mirror symmetry. Then, an external magnetic field is used to break the time reversal symmetry of the system, and a pair of degenerate photon bound states in the microcavity undergo energy level splitting, resulting in an imbalance in the photon energy in the two microcavities, forming selective excitation of a single microcavity. Finally, the selective excitation of the dual optical microcavities is related to the direction of the external magnetic field. Adjusting the direction of the external magnetic field (such as rotating 180°) can excite the optical microcavity on either side.

[0015] Beneficial effects: Compared with the prior art, the half-dislocation dual optical microcavity with selective excitation proposed in the present invention has a simple structure, can realize the selective excitation of a single optical microcavity, and has the advantages of simple principle, compact structure, high excitation ratio, low electromagnetic loss, strong anti-interference, etc. Due to topological protection, the half-dislocation microcavity does not require high manufacturing precision, is immune to disorder and defects, and is suitable for various integrated photonic devices. Since the ferrite cylindrical array has scale invariance, the operating frequency can be transplanted to the terahertz band or the optical band by directly changing the geometric size, which has wide universality. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the three-dimensional model structure of an embodiment of the present invention.

[0017] Figure 2 It is a schematic diagram of constructing a half-dislocation ferrite cylinder array according to an embodiment of the present invention.

[0018] Figure 3 This is a diagram of the electric field distribution of a point source excited by a magnetic field directed inward along a straight surface in an embodiment of the present invention.

[0019] Figure 4 This is a diagram of the electric field distribution of the embodiment of the present invention when a point source is excited under the action of a magnetic field directed outward along a straight surface.

[0020] Figure 5 Graphs showing electromagnetic transmission spectra of optical microcavities with different half-dislocations in the embodiments of the present invention. DETAILED DESCRIPTION

[0021] The present invention is further illustrated below in conjunction with the accompanying drawings and specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. After reading the present invention, modifications to various equivalent forms of the present invention by those skilled in the art all fall within the scope defined by the appended claims of the present application.

[0022] The embodiment of the present invention discloses a selectively excited half-dislocation dual optical microcavity, comprising a ferrite cylinder half-dislocation array 1, a parallel plate waveguide 2 and an electromagnetic absorption boundary 3. Among them, the ferrite cylinder half-dislocation array is a structure formed by arranging ferrite cylinders in a rectangular lattice and embedding a half-row of ferrite cylinders along the center line. The formation method is as follows: first, ferrite cylinders are arranged in a rectangular lattice to form a photonic crystal, and the photonic crystal is divided into two upper and lower sub-lattices. Then, a half-row of ferrite cylinders is embedded along the center line of the upper sub-lattice. The embedded half-row ferrite cylinders squeeze the ferrite cylinders on both sides of the center line of the upper sub-lattice, causing the cylinders on both sides to move to the left and right directions respectively. At the same time, the ferrite cylinders at the junction of the upper sub-lattice and the lower sub-lattice produce lattice dislocations due to extrusion. According to the extrusion deformation, the position of the ferrite cylinders at the junction is adjusted to obtain a pair of half-dislocation microcavities located at the junction of the upper and lower sub-lattices. In this embodiment, two half-dislocation microcavities are respectively located in the middle area of ​​the left area and the right area divided by the center line. A microcavity with an opening facing upward is formed by embedding a half-row of ferrite columns into the upper sub-lattice and adjusting the position of the ferrite columns at the interface between the upper sub-lattice and the upper and lower sub-lattices to both sides. The four sides of the ferrite half-dislocation column array are surrounded by electromagnetic absorption materials. The ferrite column half-dislocation array and the electromagnetic absorption material are both arranged between two parallel plate waveguides. In this embodiment, the parallel plate waveguide is a metal aluminum plate. The sample size is 264mm×324mm×10mm.

[0023] like Figure 1 As shown, a selectively excited half-dislocation dual optical microcavity design proposed in an embodiment of the present invention is based on a two-dimensional half-dislocation array. The main component of the ferrite cylinder is yttrium iron garnet (YIG), with a relative dielectric constant of 15.26 and a saturation magnetization of 1884 Gauss. The lattice constants of the ferrite cylinder array along the x-direction and the y-direction are a and x and a y , a y =2*a x (In this example, a x =12mm, a y =24mm). Ferrite cylinder height h = 0.83a x , the radius of the dielectric column r = 0.16a x The half-dislocation array is surrounded by electromagnetic absorption material to prevent unnecessary electromagnetic leakage.

[0024] like Figure 2 As shown in the figure, the construction process of the ferrite cylindrical half-dislocation array is as follows: (1) Construct a ferrite cylindrical array based on a rectangular lattice. The array satisfies translational symmetry, and the lattice constants along the x-direction and y-direction are a and a respectively. x and a y(2) A pair of half-dislocation optical microcavities 4 with mirror symmetry is constructed by inserting half a row of ferrite cylinders 5 along the center line of the rectangular array. The electromagnetic wave is excited by a point source 6. The electromagnetic excitation source is placed above or below the middle row of ferrite cylinders, and the detection source is placed at the geometric center of the half-dislocation optical microcavity.

[0025] Figure 3 It is shown that in the selectively excited half-dislocation dual optical microcavity design proposed in the present invention, when the direction of the external magnetic field is perpendicular to the array plane and points outward (in the +z-axis direction), the electric field intensity of the left half-dislocation optical microcavity (white trapezoidal area) is significantly higher than that of the right half-dislocation optical microcavity.

[0026] Figure 4 It is shown that in the selectively excited half-dislocation dual optical microcavity design proposed in the present invention, when the direction of the external magnetic field is perpendicular to the array plane and inward (-z axis direction), the electric field intensity of the right half-dislocation optical microcavity (white trapezoidal area) is significantly higher than that of the left half-dislocation optical microcavity.

[0027] Figure 5 The electromagnetic transmission spectra of different half-dislocation optical microcavities in the selectively excited half-dislocation dual optical microcavity design proposed in the present invention are shown. At the frequency f = 12.25 GHz (black arrow), the direction of the external magnetic field is perpendicular to the array plane and outward ( Figure 5 The transmission spectrum S21 (solid line) of the left half-dislocation optical microcavity is significantly higher than that of the right half-dislocation optical microcavity (dashed line). When the external magnetic field is perpendicular to the array plane and inward ( Figure 5 The transmission spectrum S21 (dashed line) of the right half-dislocation optical microcavity is significantly higher than the S21 (solid line) of the left half-dislocation optical microcavity.

[0028] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A selectively excited half-dislocation dual optical microcavity, characterized in that: The invention comprises a ferrite cylinder half-dislocation array, a parallel plate waveguide and an electromagnetic absorption material. The formation method of the ferrite cylinder half-dislocation array is as follows: firstly, ferrite cylinders are arranged in a rectangular lattice to form a photonic crystal, wherein the photonic crystal is divided into an upper and a lower sub-lattice; then, a half-row of ferrite cylinders are embedded along the center line of the upper sub-lattice, and the embedded half-row of ferrite cylinders squeezes the ferrite cylinders on both sides of the center line of the upper sub-lattice, causing the cylinders on both sides to move to the left and right directions respectively; at the same time, the ferrite cylinders at the junction of the upper sub-lattice and the lower sub-lattice generate lattice dislocations due to squeezing; the positions of the ferrite cylinders at the junction are adjusted according to the squeezing deformation to obtain a pair of half-dislocation microcavities located at the junction of the upper and lower sub-lattices; the half-dislocation array formed by the upper and lower sub-lattices is placed between the parallel plate waveguides; the four boundaries are all covered with electromagnetic absorption materials; and the direction of the external magnetic field is perpendicular to the array plane.

2. The selectively excited half-dislocation dual optical microcavity according to claim 1, characterized in that: The photonic crystal formed by arranging the ferrite columns in a rectangular lattice has at least 22 rows of ferrite columns.

3. The selectively excited half-dislocation dual optical microcavity according to claim 1, characterized in that: The ferrite cylindrical half dislocation array satisfies mirror symmetry, and the lattice constant in the length direction of the rectangular lattice arrangement is twice the lattice constant in the width direction.

4. The selectively excited half-dislocation dual optical microcavity according to claim 1, characterized in that: The two half-dislocation microcavities are respectively located on the left and right sides of the midline. By embedding half a row of ferrite cylinders into the upper sub-lattice along the midline, the additionally embedded ferrite cylinders cause extrusion deformation to the ferrite cylinders on both sides of the midline of the upper sub-lattice, and also cause lattice dislocation at the interface between the upper and lower sub-lattices, forming two half-dislocation microcavities with openings facing upward.

5. The selectively excited half-dislocation dual optical microcavity according to claim 1, characterized in that: The ferrite cylinder is a yttrium iron garnet cylinder.

6. The selectively excited half-dislocation dual optical microcavity according to claim 1, characterized in that: The two half-dislocation microcavities in the ferrite cylindrical half-dislocation array are respectively located on two sides of the array centerline, and the two half-dislocation microcavities are mirror-symmetrical along the array centerline.

7. The selectively excited half-dislocation dual optical microcavity according to claim 1, characterized in that: The electromagnetic excitation source is placed above or below the middle row of ferrite cylinders.

8. The selectively excited half-dislocation dual optical microcavity according to claim 1, characterized in that: The electromagnetic excitation source is a point source placed at the center of the line connecting the two half-dislocation optical microcavities.

9. The selectively excited half-dislocation dual optical microcavity according to claim 1, characterized in that: The detection source is placed at the geometric center of the half-dislocation optical microcavity.

10. The selectively excited half-dislocation dual optical microcavity according to claim 1, characterized in that: A single optical microcavity can be selectively excited by adjusting the direction of the magnetic field.

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