本研究計畫的目標是在理論上研究左手介質與光子晶體近場透鏡的種種物理特性，以期對此類透鏡的成像機制、像解析度，以及未來的應用前景有一個清楚的瞭解。研究的重點包括： 1. 比較左手介質與光子晶體負折射近場透鏡的成像特性之異同。預期除吸收性造成的差異外，非均向性（Anisotropy），部分帶隙效應（Partial gap effect）與顆粒性（Granularity）將是此兩種近場透鏡的最主要差異。由於顆粒性（光子晶體由具有空間週期性的晶胞構成）意味著空間的均勻性有一個限度，故成像解析度將被此一特性所限制。我們將嘗試對光子晶體透鏡建立更精確的等效介質模型，以對其成像特性做更好的描述。 2. 研究此兩種近場透鏡的動態行為（Dynamical behaviors）。由於左手介質近場透鏡的次波長成像依賴的是消散波在介質板內的放大效應，故欲達成次波長成像必須在介質板表面激發出大振幅的表面波（在極端次波長成像的情況下介面波振幅可達成像區振幅的100 倍以上），也就是所謂的表面電漿偏極子（Surface-plasmon-polariton）。要累積此一介面能量，系統在趨向穩態的過程中將經歷較長時間的暫態效應。我們將研究光子晶體近場透鏡系統是否也有此種長時間暫態效應。 The aim of this project is to study theoretically the physical properties of the left-handed material and photonic crystal near-field lenses. We expect that a complete understanding of these properties such as the imaging mechanism and the image resolution would help us to design useful new photonic devices. We will focus our attention on the following items. 1. The comparison of the imaging properties of these two kinds of near-field lenses. The first and apparent difference is their different absorption characteristics. Besides, a photonic crystal as a medium has the properties of anisotropy, the partial band gap effect, and the granularity, and these characteristics make it different from a homogeneous left-handed material medium. The granularity for a medium means that there is a limit on the space homogeneity (the unit cell of a photonic crystal), and the image resolution must be limited by this characteristic. We will try to construct an accurate effective medium model to have better prediction ability about the imaging properties of the photonic crystal near-field lens. 2. The comparison of the dynamical behaviors of these two kinds of near-field lenses. A left-handed material slab lens has the ability of amplifying the evanescent waves, and this makes it possible to focus light into a subwavelength region. For a left-handed material slab, the wave amplification is formed by the coupling of the source wave and the surface-plasmon-polaritons on the boundaries of the slab. In the extremely subwavelength limit, these surface waves may have amplitudes 100 times that of the image field. To establish such a field pattern, the system has to wait a long time to become stationary – a long time transient effect. We will investigate if the photonic crystal near-field lens also has such property. 研究期間：9308 ~ 9407
