Surface-enhanced Raman scattering (SERS) is increasing in significance as a bioanalytical tool. Novel nanostructured metal substrates are required to improve performances and versatility of SERS spectroscopy. In particular, as biological tissues are relatively transparent in the infrared wavelength range, SERS-active materials suitable for infrared laser excitation are needed. Nanowires appear interesting in this respect as they show a very broad localized surface plasmon resonance band, ranging from near UV to near infrared wavelengths. The SERS activity of silver nanowires has been tested at three wavelengths and a fair enhancement at 1064 and 514 nm has been observed, whereas a very weak enhancement was present when exciting close to the nanowire extinction maximum. These experimentally measured optical properties have been contrasted with finite element method simulations. Furthermore, laser-induced optoacoustic spectroscopy measurements have shown that the extinction at 1064 nm is completely due to scattering. This result has an important implication that no heating occurs when silver nanowires are utilized as SERS-active substrates, thereby preventing possible thermal damage.

中文翻译：

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银纳米线作为红外活性材料，用于表面增强拉曼散射†

作为生物分析工具，表面增强拉曼散射（SERS）的重要性正在提高。需要新型的纳米结构金属基底来改善SERS光谱学的性能和多功能性。特别是，由于生物组织在红外波长范围内相对透明，因此需要适合红外激光激发的SERS活性材料。纳米线在这方面显得很有趣，因为它们显示了非常宽的局部表面等离子体共振带，范围从近紫外线到近红外线。已经在三个波长下测试了银纳米线的SERS活性，并且观察到在1064和514 nm处有明显的增强，而当激发接近纳米线最大消光时，则存在非常弱的增强。这些实验测量的光学特性已与有限元方法模拟进行了对比。此外，激光诱导的光声光谱测量表明，在1064 nm处的消光完全是由于散射。该结果具有重要的意义，即当将银纳米线用作SERS活性基板时不会发生加热，从而防止了可能的热损坏。