论文标题
使用放大介质克服介电谐振器大小的衍射极限
Overcoming the diffraction limit on the size of dielectric resonators using an amplifying medium
论文作者
论文摘要
现有在纳米级的光定位方法使用具有负介电常数的结构，通过利用亚波长等离子共振或具有高折射率指数的介电结构，从而降低波长。在本文中，我们根据活性介质对介电谐振器模式的修改提供了这两种方法的替代方法。我们表明，活性培养基可以促进介电结构中的亚波长度定位。我们考虑了介电介质中尺寸的介电层大大小于一半波长的光，并证明在活性介质中有一定的增益值，在层边界处的反射相反射的相变可补偿由于层上层的传播而导致的相变。在增益的这个值下，增益辅助模式形式，其中电磁波往返过程中的相移为零。这种增益辅助模式仅以介电介质的正增益存在，可用于创建介电激光器和亚波长度的传感器。
Existing methods for the localization of light at the nanoscale use either a structure with negative permittivity, by exploiting subwavelength plasmonic resonances, or a dielectric structure with a high refractive index, which reduces the wavelength. In this paper, we provide an alternative to these two methods based on a modification of the modes of dielectric resonators by means of an active medium. We show that an active medium can promote subwavelength light localization in the dielectric structure. We consider a dielectric layer of size substantially smaller than a half-wavelength of light in the dielectric medium, and demonstrate that at a certain value of gain in the active medium, the phase change on reflection at the layer boundaries compensates for the change in phase due to propagation over the layer. At this value of the gain, the gain-assisted mode forms, in which the phase shift during a round trip of the electromagnetic wave is zero. This gain-assisted mode exists only at a positive gain in the dielectric medium, and can be used to create dielectric lasers and sensors of subwavelength size.
