Kordi Mahdi, Mirsalehi Mir Mojtaba
Appl Opt. 2017 Jun 1;56(16):4772-4778. doi: 10.1364/AO.56.004772.
A slab metamaterial lens with a refractive index of -1 is capable of producing a perfect image, since it transfers all the plane waves from the object plane to the image plane without creating any distortion in their amplitudes and phases. However, its practical implementation encounters several challenges. In this paper, a lossless slab metamaterial lens is investigated using the ray-tracing technique. We also discuss propagating waves and evanescent waves and investigate an imaging system based on an ellipsoidal cavity. It is shown that since an ellipsoidal cavity transfers the beams from one of its foci to the other with the same amplitude and phase, it acts similarly to a metamaterial slab lens of n=-1. Therefore, this structure can be used as a subwavelength resolution imaging system. Also, it does not suffer from chromatic aberration, since all the rays transmitted from one focus pass through the other independent of the wavelength. Another important advantage of this system, compared to metamaterial-based superlenses, is that it can operate at any frequency as long as the dimensions of the cavity are much larger than the wavelength.
折射率为 -1 的平板超材料透镜能够产生完美图像，因为它能将物平面的所有平面波传输到像平面，且不会在其振幅和相位上产生任何失真。然而，其实际应用面临诸多挑战。本文采用光线追踪技术对无损平板超材料透镜进行了研究。我们还讨论了传播波和倏逝波，并研究了基于椭球腔的成像系统。结果表明，由于椭球腔能将光束从其一个焦点以相同的振幅和相位传输到另一个焦点，其作用类似于折射率为 n = -1 的超材料平板透镜。因此，这种结构可作为亚波长分辨率成像系统。此外，它不存在色差，因为从一个焦点传输的所有光线都能通过另一个焦点，与波长无关。与基于超材料的超透镜相比，该系统的另一个重要优势在于，只要腔的尺寸远大于波长，它就能在任何频率下工作。
