Enabling Ultrasensitive Optical Measurements with Plasmonics

利用等离激元实现超灵敏光学测量

• 批准号: RGPIN-2015-04298
• 负责人: LagugnéLabarthet, François
• 金额: $ 3.28万
• 依托单位: University of Western Ontario
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=656362
• 关键词: Enabling; Ultrasensitive; Optical; Measurements; Plasmonics

Metallic nanostructures have enabled critical advances in a variety of applications ranging from photonic devices that perform a logical function, medical research to better target tumors for further localized photothermal treatment, solar cells technology to high sensitivity optical sensors. An electromagnetic field such as a laser light confined in the vicinity of a single silver or gold nanoparticle or an ensemble of interacting particles, displays resonances that are dependent on the opto-geometric properties of the nanostructure. Under the right experimental conditions, the excitation of such local resonance can yield enhancement of the electromagnetic field by several orders of magnitude which can be exploited for ultrahigh sensitivity optical spectroscopy. Its application in materials science and biomaterial is tremendous offering improved spatial resolution and sensitivity at a level down to the detection of a single molecule. This research program aims at providing solutions to enable ultrahigh sensitivity measurements in optical spectroscopy and is articulated along four principal objectives:****(i) High spatial resolution vibrational spectroscopy of biomaterials using tip-enhanced Raman spectroscopy will be conducted. We will focus on DNA strands and develop a strategy to better evaluate lesions in DNA strands. Our setup offers a resolution in the 10 nm range allowing one to probe and manipulate a sequence of a few bases that compose the DNA. (ii) Plasmon mediated detection of biomolecular exchanges between neuronal cells will be developed using surface-enhanced effects. We will combine surface patterning to direct cell growth over plasmonic sensor enabling to probe chemical and biochemical exchanges occurring in the vicinity of the cell membrane. Fluorescence and Raman enhancements will be used to probe chemical exchanges. (iii) We will develop strategies to design and optimize mid-infrared plasmonics platforms. To yield a large enhancement over a wide spectral domain in the mid-IR we will develop fractal plasmonic structures. Because of the small size (typically 100x100 micron square) of the plasmonic platform, the use of a bright infrared source such as the one accessible at the Canadian Light Source will be of great value for the study of these platforms. (iv) Finally, nonlinear optical effects generated in plasmonic structures will be conducted. Non-centrosymmetric geometries should lead to large optical nonlinearities will be probed by second-harmonic generation microscopy. Ultimately the chirality of the plasmonic structure will also be a parameter that will be valued for chiral sensing using nonlinear effects opening a variety of applications in optical biosensing.This program aims at providing cutting-edge approaches in nanoscale imaging to probe the intimate nature of chemical and biochemical processes involved in the most basic cellular processes. **

金属纳米结构在各种应用中取得了关键进展，从执行逻辑功能的光子器件、医学研究到更好地靶向肿瘤以进行进一步的局部光热治疗、太阳能电池技术到高灵敏度光学传感器。电磁场（例如限制在单个银或金纳米粒子或相互作用粒子集合附近的激光）显示出取决于纳米结构的光几何特性的共振。在正确的实验条件下，这种局部共振的激发可以使电磁场增强几个数量级，可用于超高灵敏度光谱。它在材料科学和生物材料中的应用是巨大的，可在检测单个分子的水平上提供改进的空间分辨率和灵敏度。该研究计划旨在提供解决方案，以实现光谱学中的超高灵敏度测量，并围绕四个主要目标进行阐述：****(i) 将使用尖端增强拉曼光谱法对生物材料进行高空间分辨率振动光谱学。我们将重点关注 DNA 链并制定策略来更好地评估 DNA 链的损伤。我们的装置提供 10 nm 范围内的分辨率，允许人们探测和操纵组成 DNA 的几个碱基序列。 (ii) 将利用表面增强效应开发等离激元介导的神经元细胞之间生物分子交换的检测。我们将结合表面图案来引导细胞在等离子体传感器上生长，从而能够探测细胞膜附近发生的化学和生化交换。荧光和拉曼增强将用于探测化学交换。 (iii) 我们将制定设计和优化中红外等离子体平台的策略。 为了在中红外宽光谱域内产生大幅增强，我们将开发分形等离子体结构。由于等离激元平台尺寸较小（通常为 100x100 微米见方），因此使用明亮的红外光源（例如加拿大光源处的光源）对于这些平台的研究具有重要价值。 (iv)最后，将研究等离子体结构中产生的非线性光学效应。非中心对称几何形状会导致大的光学非线性，将通过二次谐波产生显微镜进行探测。最终，等离子体结构的手性也将成为使用非线性效应进行手性传感的重要参数，从而在光学生物传感中开辟多种应用。该项目旨在提供纳米级成像的尖端方法，以探测化学的亲密性质和涉及最基本细胞过程的生化过程。 **