CN103399369B - Based on the transmission light device of artificial electromagnetic material - Google Patents

本发明提供的是一种基于人工电磁材料的传输光器件。包括：第一层金属结构层、间隔层和第二层金属结构层；间隔层是透明的光敏聚合物，厚度为百纳米量级；第一层金属结构层和第二层金属结构层分别位于间隔层两侧的表面，第一层金属结构层和第二层金属结构层均由周期性排列的基本单元构成，第一层金属结构层和第二层金属结构层的厚度均为20-60nm；第一层金属结构层和第二层金属结构层的基本单元的结构形状相同。本发明的传输光器件在两个波段具有很强的线偏振转换特性，实现了双波段的单向传输。

The invention provides a transmission optical device based on artificial electromagnetic material. Including: the first metal structure layer, the spacer layer and the second metal structure layer; the spacer layer is a transparent photosensitive polymer with a thickness of hundreds of nanometers; the first metal structure layer and the second metal structure layer are respectively located The surfaces on both sides of the spacer layer, the first metal structure layer and the second metal structure layer are composed of periodically arranged basic units, and the thickness of the first metal structure layer and the second metal structure layer is 20-60nm ; The structural shapes of the basic units of the first metal structure layer and the second metal structure layer are the same. The transmission optical device of the invention has strong linear polarization conversion characteristics in two wave bands, and realizes unidirectional transmission in two wave bands.

基于人工电磁材料的传输光器件Transmitting Optical Devices Based on Artificial Electromagnetic Materials

技术领域technical field

本发明涉及一种电磁波的传输控制器件，尤其涉及一种基于人工电磁材料的传输光器件。The invention relates to an electromagnetic wave transmission control device, in particular to a transmission optical device based on artificial electromagnetic materials.

背景技术Background technique

人工电磁超材料（Metamaterials）是人工设计的具有亚波长结构并呈现天然材料不具备的超常性质的材料，其独特新颖的物理性质和诱人的应用前景得到了国际学术界的广泛关注，被美国《科学》杂志评为2003年度十大科技成就之一，超材料引发了光子晶体之后又一个人工新型媒质的研究热潮。Artificial electromagnetic metamaterials (Metamaterials) are artificially designed materials with sub-wavelength structures and extraordinary properties that natural materials do not have. Their unique and novel physical properties and attractive application prospects have attracted widespread attention from the international academic community. "Science" magazine named it one of the top ten scientific and technological achievements in 2003. Metamaterials triggered another wave of research on artificial new media after photonic crystals.

Metamaterials中“meta”相当于英文的“beyond”，意为超越，其结构单元的尺度在亚波长量级，可以实现天然材料所没有的电磁特性，如负折射、完美透镜、隐身斗篷等。手性（Chirality）是对物体对称性的一种纯粹几何性描述，是指物体结构自身缺乏几何对称性，典型手性介质有石英、葡萄糖等。早在19世纪初，研究者就发现了石英晶片可旋转偏振光的偏振面，具有光学活性，又称为旋光现象。近年来，为了描述2维平面结构的光学性质,引入了2维手性的概念:如果一个平面物体不能通过平面内的旋转和移位与它的镜像重合，即它在结构的平面内没有线对称性，则该物体为手性结构，具有螺旋性质。人工电磁超材料的出现极大地丰富了电磁领域的研究内容，例如，手性与人工电磁超材料结合后会出现巨大的旋光效应、电磁波的非对称传输等。"meta" in Metamaterials is equivalent to "beyond" in English, which means beyond. The scale of its structural units is on the sub-wavelength level, which can realize electromagnetic properties that natural materials do not have, such as negative refraction, perfect lens, invisibility cloak, etc. Chirality is a purely geometric description of the symmetry of an object, and refers to the lack of geometric symmetry in the structure of the object itself. Typical chiral media include quartz, glucose, etc. As early as the beginning of the 19th century, researchers discovered that quartz wafers can rotate the polarization plane of polarized light, which is optically active, also known as optical rotation. In recent years, in order to describe the optical properties of 2D planar structures, the concept of 2D chirality has been introduced: if a planar object cannot coincide with its mirror image through in-plane rotation and displacement, that is, it has no lines in the plane of the structure Symmetry, the object is a chiral structure with helical properties. The emergence of artificial electromagnetic metamaterials has greatly enriched the research content in the field of electromagnetics. For example, the combination of chirality and artificial electromagnetic metamaterials will have a huge optical rotation effect and asymmetric transmission of electromagnetic waves.

非对称传输现象为光波段偏振光传输的方向调控提供了新的途径，对实现光波段隔离器、光波段二极管、偏振转换器件等超材料功能器件具有重大意义。手性材料的单向传输现象发现以来,相关研究受到了广泛关注。目前，基于人工电磁材料的光器件研究局限于单波段、单偏振态的单向传输，且偏振转换效率不高。The asymmetric transmission phenomenon provides a new way to regulate the transmission direction of polarized light in the optical band, and is of great significance for the realization of metamaterial functional devices such as optical band isolators, optical band diodes, and polarization conversion devices. Since the discovery of the one-way transport phenomenon in chiral materials, related researches have received extensive attention. At present, the research on optical devices based on artificial electromagnetic materials is limited to single-wavelength, single-polarization state unidirectional transmission, and the polarization conversion efficiency is not high.

发明内容Contents of the invention

本发明提供了一种基于人工电磁材料的传输光器件，该传输光器件能够实现双波段的传输。The invention provides a transmission optical device based on artificial electromagnetic material, which can realize dual-band transmission.

一方面，提供了一种基于人工电磁材料的传输光器件，包括：第一层金属结构层、间隔层和第二层金属结构层；间隔层是透明的光敏聚合物，厚度为百纳米量级；第一层金属结构层和第二层金属结构层分别位于间隔层两侧的表面，第一层金属结构层和第二层金属结构层均由周期性排列的基本单元构成，第一层金属结构层和第二层金属结构层的厚度均为20-60nm；第一层金属结构层和第二层金属结构层的基本单元的结构形状相同。On the one hand, a transmission optical device based on artificial electromagnetic materials is provided, including: a first metal structure layer, a spacer layer and a second metal structure layer; the spacer layer is a transparent photosensitive polymer with a thickness on the order of hundreds of nanometers ; The first layer of metal structure layer and the second layer of metal structure layer are located on the surfaces of both sides of the spacer layer, the first layer of metal structure layer and the second layer of metal structure layer are composed of periodically arranged basic units, the first layer of metal structure The thicknesses of the structural layer and the second metal structural layer are both 20-60nm; the structural shapes of the basic units of the first metallic structural layer and the second metallic structural layer are the same.

优选地，第一层金属结构层和第二层金属结构层采用贵金属材料Noblemetal。Preferably, noble metal material Noblemetal is used for the first metal structure layer and the second metal structure layer.

优选地，贵金属材料包括：金或银。Preferably, the noble metal material includes: gold or silver.

优选地，第一层金属结构层和第二层金属结构层的基本单元的结构形状相同包括：第一层金属结构层和第二层金属结构层的基本单元的结构均为双I型的结构。Preferably, the structural shapes of the basic units of the first metal structure layer and the second metal structure layer are the same: the structures of the basic units of the first metal structure layer and the second metal structure layer are double I-type structures .

优选地，第一层金属结构层和第二层金属结构层的基本单元的结构形状相同包括：第一层金属结构层和第二层金属结构层的基本单元的结构形状为连续双I型，第一层金属结构层和第二层金属结构层的基本单元的结构尺寸相同，第一层金属结构层的基本单元和第二层金属结构层的基本单元之间的旋转角为90度。Preferably, the structural shapes of the basic units of the first metal structural layer and the second metallic structural layer are the same: the structural shapes of the basic units of the first metallic structural layer and the second metallic structural layer are continuous double I type, The structural dimensions of the basic units of the first metal structure layer and the second metal structure layer are the same, and the rotation angle between the basic units of the first metal structure layer and the basic units of the second metal structure layer is 90 degrees.

优选地，第一层金属结构层和第二层金属结构层的每层金属结构膜层厚度均为20-60nm包括：第一层金属结构层和第二层金属结构层的每层金属结构膜层厚度均为50nm。Preferably, the thickness of each metal structure film of the first metal structure layer and the second metal structure layer is 20-60nm including: each metal structure film of the first metal structure layer and the second metal structure layer The layer thicknesses were all 50 nm.

优选地，上述器件还包括：红外透明介质基底，其中，红外透明介质基底和间隔层分别位于第一金属结构层的两侧。Preferably, the above-mentioned device further includes: an infrared transparent dielectric substrate, wherein the infrared transparent dielectric substrate and the spacer layer are respectively located on both sides of the first metal structure layer.

优选地，红外透明介质基底的材料是石英玻璃。Preferably, the material of the infrared transparent medium substrate is quartz glass.

上述器件可直接在自由空间使用，也可将其置于石英玻璃等红外透明介质基底材料上使用。The above-mentioned devices can be used directly in free space, or placed on infrared transparent dielectric substrate materials such as quartz glass.

在本发明中，人工电磁材料基本单元的周期为ρ，金属结构的线宽为w，间隔层厚度为t，上述器件可以工作在红外光波段。In the present invention, the period of the basic unit of the artificial electromagnetic material is ρ, the line width of the metal structure is w, and the thickness of the spacer layer is t. The above-mentioned devices can work in the infrared light band.

通过上述方案，本发明提供了一种基于人工电磁材料的双波段、双正交偏振态的单向传输光器件，通过在所设计的双层手性结构中加入狭缝来实现双波段的线偏振单向传输。该双波段单向传输器件具有结构简易、制造简单、价格低廉等优点，光波段线偏振光转换的单向传输现象很明显，有效地实现了光波段针对双正交偏振态的双波段单向传输。Through the above scheme, the present invention provides a dual-band, dual-orthogonal polarization-state unidirectional transmission optical device based on artificial electromagnetic materials, by adding slits in the designed double-layer chiral structure to realize dual-band line Polarized unidirectional transmission. The dual-band unidirectional transmission device has the advantages of simple structure, simple manufacture, and low price. The unidirectional transmission phenomenon of optical band linearly polarized light conversion is obvious, and effectively realizes dual-band unidirectional transmission of optical bands for dual orthogonal polarization states. transmission.

本发明所提出的双波段单向传输光器件具有很强的线偏振转换二向色性，双层手性结构实现了光波段线偏振光转换的单向传输。该器件将可实现光波隔离器或光波二极管，对红外光波人工电磁材料功能器件的发展意义重大。The dual-band unidirectional transmission optical device proposed by the invention has strong linear polarization conversion dichroism, and the double-layer chiral structure realizes unidirectional transmission of optical band linear polarization conversion. The device can realize a light wave isolator or a light wave diode, which is of great significance to the development of infrared light wave artificial electromagnetic material functional devices.

附图说明Description of drawings

图1是根据本发明实施例的双波段单向传输光器件S的立体结构示意图；FIG. 1 is a schematic diagram of a three-dimensional structure of a dual-band unidirectional transmission optical device S according to an embodiment of the present invention;

图2是根据本发明实施例的双波段单向传输光器件S（正面）及其基本结构参数；Fig. 2 is a dual-band unidirectional transmission optical device S (front) and its basic structural parameters according to an embodiment of the present invention;

图3是根据本发明实施例的双波段单向传输光器件S的工作原理示意图；3 is a schematic diagram of the working principle of a dual-band unidirectional transmission optical device S according to an embodiment of the present invention;

图4是根据本发明实施例的双波段单向传输光器件S正向透射幅值（ ）曲线；Figure 4 shows the forward transmission amplitude of the dual-band unidirectional transmission optical device S according to an embodiment of the present invention ( )curve;

图5是根据本发明实施例的双波段单向传输光器件S反向透射幅值（ ）曲线；Fig. 5 shows the reverse transmission amplitude ( )curve;

图6是根据本发明实施例的双波段单向传输光器件S的非对称传输系数曲线。Fig. 6 is an asymmetric transmission coefficient curve of a dual-band unidirectional transmission optical device S according to an embodiment of the present invention.

具体实施方式detailed description

下面结合附图举例对本发明做更加详细的描述。The present invention will be described in more detail below with examples in conjunction with the accompanying drawings.

实施例1：Example 1:

本发明的实施方式如图1-2所示，双波段单向传输光器件S包括间隔层2和金属材料层1、3；间隔层位于金属材料层1和3之间，采用光敏聚合物（PC403），用于支撑金属材料层1和3，其厚度t=50nm；金属材料层1和3分别位于间隔层两侧的表面，每层由周期性排列的连续双I型金属材料层基本单元构成，金属材料层基本单元的参数如下，周期ρ=1200nm，金属线的宽度w=200nm，长度l1=495nm,l2=400nm，l3=990nm，b=210nm，t1=t2=50nm，其中，t1是金属材料层1的厚度，t2是金属材料层3的厚度。金属材料层1即为第一层金属结构层，金属材料层3即为第二层金属结构层。需要说明的是，上述尺寸仅是一种优选的方案，并不用于限定本发明的保护范围。本领域技术人员能够想到，类似的其他尺寸也能实现本发明，例如，金属材料层1的厚度和金属材料层3的厚度可以是20-60nm。本实施例中的器件可以在自由空间使用。Embodiments of the present invention are shown in Figure 1-2, the dual-band unidirectional transmission optical device S includes a spacer layer 2 and metal material layers 1, 3; the spacer layer is located between the metal material layers 1 and 3, using photosensitive polymer ( PC403), used to support metal material layers 1 and 3, with a thickness of t=50nm; metal material layers 1 and 3 are located on the surfaces of both sides of the spacer layer, and each layer is composed of periodically arranged continuous double I-type metal material layer basic units Composition, the parameters of the basic unit of the metal material layer are as follows, the period ρ=1200nm, the width of the metal line w=200nm, the length l1=495nm, l2=400nm, l3=990nm, b=210nm, t1=t2=50nm, where t1 is the thickness of the metal material layer 1, and t2 is the thickness of the metal material layer 3. The metal material layer 1 is the first metal structure layer, and the metal material layer 3 is the second metal structure layer. It should be noted that the above dimensions are only a preferred solution, and are not intended to limit the protection scope of the present invention. Those skilled in the art can imagine that other similar dimensions can also implement the present invention, for example, the thickness of the metal material layer 1 and the thickness of the metal material layer 3 can be 20-60 nm. The device in this embodiment can be used in free space.

下面再结合附图3进一步说明实施方案，首先为单向传输器S设置一个XYZ坐标轴作为工作空间，Z轴垂直于单向传输器的表面。如图3（a）所示，X方向偏振的线偏振光4沿Z轴正向垂直入射到上述非对称传输器表面后，透射光为5。再令其沿Z轴负向垂直入射到上述非对称传输器表面，透射光为6，如图3（b）。分别计算其透射率（透射波振幅/入射波振幅），下标i、j分别代表入射光和透射光的偏振态，上标d代表入射光的波矢方向，沿Z轴负向则为+，Z轴正向则为-。双波段单向传输光器件S正向透射幅值（ ）曲线如图4所示，从图中可以看出，和分别达到极值，偏振转换程度最高。双波段单向传输光器件S反向透射幅值（ ）曲线如图5所示，从图中可以看出，在103.76THz和146.72THz，和分别达到极值，偏振转换程度最高，从而实现双波段单向光传输。图6则是双波段单向传输光器件S的非对称传输系数曲线， The embodiment is further described below in conjunction with accompanying drawing 3. First, an XYZ coordinate axis is set for the one-way conveyor S as a working space, and the Z axis is perpendicular to the surface of the one-way conveyor. As shown in Fig. 3(a), after the linearly polarized light 4 polarized in the X direction is vertically incident on the surface of the asymmetric transmitter along the Z axis, the transmitted light is 5. Then let it be vertically incident on the surface of the above-mentioned asymmetric transmitter along the negative direction of the Z axis, and the transmitted light is 6, as shown in Figure 3(b). Calculate its transmittance separately (transmitted wave amplitude/incident wave amplitude), the subscripts i and j represent the polarization states of the incident light and the transmitted light, respectively, and the superscript d represents the wave vector direction of the incident light, along the negative direction of the Z axis, it is +, and the positive direction of the Z axis is -. Forward transmission amplitude of dual-band unidirectional transmission optical device S ( ) curve is shown in Figure 4, it can be seen from the figure that, and Respectively reaching extreme values, the degree of polarization conversion is the highest. Dual-band unidirectional transmission optical device S reverse transmission amplitude ( ) curves are shown in Figure 5. It can be seen from the figure that at 103.76THz and 146.72THz, and Respectively reaching the extreme value, the degree of polarization conversion is the highest, thus realizing the dual-band unidirectional optical transmission. Figure 6 is the asymmetric transmission coefficient curve of the dual-band unidirectional transmission optical device S,

通过本实施例的方案，能够实现双波段单向传输。Through the solution of this embodiment, dual-band unidirectional transmission can be realized.

实施例2：Example 2:

本实施例提供了一种双波段单向传输光器件，该器件是在实施例1上进行了改进，将实施例1中的整体结构置于红外透明基底上，即，红外透明介质基底和所述间隔层分别位于所述第一金属结构层的两侧。该器件在红外波段也可实现双波段、双偏振态（X和Y）的单向光传输。优选地，该红外透明基底的材料是石英玻璃。This embodiment provides a dual-band unidirectional transmission optical device, which is improved on Embodiment 1, and the overall structure in Embodiment 1 is placed on the infrared transparent substrate, that is, the infrared transparent medium substrate and the The spacer layers are respectively located on both sides of the first metal structure layer. The device can also achieve dual-band, dual-polarization (X and Y) unidirectional light transmission in the infrared band. Preferably, the material of the infrared transparent substrate is quartz glass.