高アスペクト比キャビティ内への閉じ込め効果を用いた高感度バイオマーカー検出手法

在本研究中，设计并制作了由金属包覆纳米鳍组成的三维悬浮纳米鳍-腔结构。由于等离子体热点与纳米鳍腔的耦合，使得强光流在纳米鳍腔中持续形成环路，使得纳米鳍腔结构的光学特性在共振波长上由高透明变为高反射。因此，在从近红外到红外区域的很宽范围内实现了强且可调谐的反射共振。通过改变纳米翅腔的周期可以调谐强反射带，这为利用悬浮纳米翅腔结构的微系统来操纵纳米翅腔提供了一种很有前途的方法。综上所述，由于严格的SPR条件，产生了强的窄带反射共振，其带宽在半宽处为92 nm，在不同阶模式下，近红外到红外区域的质量因子高达60，并且通过改变纳米鳍的周期也可调谐。虽然这项研究主要集中在红外和近红外区域的滤波和开关特性，这是研究指纹区域和生物传感的主要兴趣，但纳米鳍腔结构可以设计成适合许多其他应用的需求，在可见光到太赫兹区域。纳米鳍腔结构的特性为设计带通滤波器、光开关、传感器以及指纹领域的应用提供了新的途径。

In this research, a three-dimensional suspended nanofin-cavity structure consisting of metal-coated nanofins was designed and fabricated. Due to the coupling of plasmonic hot spots to the nanofin-cavities, strong optical flows turning light in a loop are sustained in the nanofin cavities and the optical properties of the nanofin-cavity structure change from being highly transparent to highly reflective at the resonance wavelength. Therefore, strong and tunable reflected resonances are realized in a very wide range from the NIR to IR region. A strong reflectance band can be tuned by varying the period of the nanofin cavities, and this presents a promising way to manipulate the nanofin cavities through the use of microsystems taking advantage of the suspended nanofin-cavity structure. In summary, a strong and narrow-band reflectance resonance due to the stringent condition of SPR arises with a bandwidth having a full width at half-maximum of 92 nm and a quality factor as large as 60 from the NIR to IR region using different order modes and also tunability by varying the period of the nanofins. Although this study concentrated on the filtering and switching properties in the IR and NIR region, which are of major interest for studying the fingerprint region and biosensing, the nanofin-cavity structure can be designed to suit the requirements of many other applications in the visible to the terahertz regions. The characteristics of the nanofin-cavity structure provide a new way to design band-pass filters, optical switches, sensor, and applications in the fingerprint region.