Dusa Arpad, Madzharova Fani, Kneipp Janina
Department of Chemistry, Humboldt-Universität zu Berlin, Berlin, Germany.
Front Chem. 2021 May 17;9:680905. doi: 10.3389/fchem.2021.680905. eCollection 2021.
Surface enhanced hyper Raman scattering (SEHRS) can provide many advantages to probing of biological samples due to unique surface sensitivity and vibrational information complementary to surface-enhanced Raman scattering (SERS). To explore the conditions for an optimum electromagnetic enhancement of SEHRS by dimers of biocompatible gold nanospheres and gold nanorods, finite-difference time-domain (FDTD) simulations were carried out for a broad range of excitation wavelengths from the visible through the short-wave infrared (SWIR). The results confirm an important contribution by the enhancement of the intensity of the laser field, due to the two-photon, non-linear excitation of the effect. For excitation laser wavelengths above 1,000 nm, the hyper Raman scattering (HRS) field determines the enhancement in SEHRS significantly, despite its linear contribution, due to resonances of the HRS light with plasmon modes of the gold nanodimers. The high robustness of the SEHRS enhancement across the SWIR wavelength range can compensate for variations in the optical properties of gold nanostructures in real biological environments.
表面增强超拉曼散射（SEHRS）由于其独特的表面敏感性以及与表面增强拉曼散射（SERS）互补的振动信息，在探测生物样品方面具有诸多优势。为了探索生物相容性金纳米球和金纳米棒二聚体实现SEHRS最佳电磁增强的条件，针对从可见光到短波红外（SWIR）的广泛激发波长范围进行了时域有限差分（FDTD）模拟。结果证实了由于双光子非线性激发效应导致激光场强度增强所起的重要作用。对于波长大于1000 nm的激发激光，尽管超拉曼散射（HRS）场是线性贡献，但由于HRS光与金纳米二聚体的等离子体模式发生共振，其在SEHRS增强中起显著作用。SEHRS增强在整个SWIR波长范围内具有很高的稳健性，能够补偿实际生物环境中金纳米结构光学性质的变化。
