Hasan Mehdi, Simpson Jamesina J
Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, Utah 84112, USA.
Appl Opt. 2013 Aug 1;52(22):5420-5. doi: 10.1364/AO.52.005420.
A design challenge for photodiodes yielding both high speed and responsivity is the necessity to concentrate incident light into a subwavelength active volume region. Photonic nanojets have been reported in the literature as a means to focus an incident plane wave to a subwavelength-waist propagating beam with applications ranging from next-generation DVDs to characterizing subwavelength features within dielectric targets. In the present work, a new application of photonic nanojets is proposed, focusing electromagnetic energy into a photodiode. Three-dimensional finite-difference time-domain solutions are conducted to determine the advantages of photonic nanojet-enhanced photodiodes at near-infrared wavelengths (1310 nm). We find that photonic nanojets provide a factor of 26 increase in the volume-integrated electric field within the subwavelength active volume of the photodiode of size 0.0045 μm³. Furthermore, this increase is achieved independent of the incident polarization and over a broad bandwidth. Photonic nanojets may thus serve as an attractive alternative to plasmonics for some applications.
对于同时实现高速和高响应度的光电二极管而言，一个设计挑战在于需要将入射光集中到一个亚波长有源体积区域。光子纳米喷流在文献中已有报道，它是一种将入射平面波聚焦成亚波长束腰传播光束的方法，其应用范围涵盖从下一代DVD到表征介电目标内的亚波长特征等领域。在本工作中，提出了光子纳米喷流的一种新应用，即将电磁能量聚焦到光电二极管中。进行了三维时域有限差分求解，以确定光子纳米喷流增强型光电二极管在近红外波长（1310 nm）下的优势。我们发现，光子纳米喷流使尺寸为0.0045μm³的光电二极管亚波长有源体积内的体积积分电场增加了26倍。此外，这种增加与入射偏振无关，且在很宽的带宽范围内都能实现。因此，对于某些应用而言，光子纳米喷流可能是等离子体激元学的一个有吸引力的替代方案。
