Exploiting Anisotropy of Plasmonic Nanostructures with Polarization Modulation Infrared Linear Dichroism Microscopy (µPM‐IRLD)

Abstract

Metallic nanostructures that exhibit plasmon resonances in the mid‐infrared range are of particular interest for a variety of optical processes where the infrared excitation and/or emission can be enhanced. This plasmon‐mediated enhancement can potentially be used toward highly sensitive detection of an analyte(s) by techniques such as surface‐enhanced infrared absorption (SEIRA). To maximize the SEIRA enhancement, it is necessary to prepare highly tuned plasmonic resonances over a defined spectral range that can span over several microns. Noteworthy, nanostructures with anisotropic shapes exhibit multiple resonances that can be exploited by controlling the polarization of the input light. This study demonstrates the role of polarization‐modulation infrared linear dichroism coupled to microscopy measurements (µPM‐IRLD) as a powerful means to explore the optical properties of anisotropic nanostructures. Quantitative µPM‐IRLD measurements are conducted on a series of dendritic fractals as model structures to explore the role of structural anisotropy on the resulting surface‐enhanced infrared absorption and sensing application. Once functionalized with an analyte, the µPM‐IRLD SEIRA results highlight that it is possible to selectively enhance further vibrational modes of analytes making use of the structural anisotropy of the metallic nanostructure.

Carving Plasmon Modes in Silver Sierpiński Fractals

“…Conductive nanostructures support surface plasmon resonance (SPR) modes when subjected to resonant optical irradiation conditions. Such plasmon modes are localized in the vicinity of the nanostructures and show local enhancement of the impinging electromagnetic field that can be utilized for a variety of applications such as antennas for emission or collection purposes, sensing and filtering devices, − chiral imaging and sensing, − surface chemistry, , photovoltaic cells, or simply for their ability to increase drastically the sensitivity of common spectroscopy measurements (Raman, infrared, and fluorescence) through a surface-enhanced mechanism. − …”

Adhesion Anisotropy Substrate with Janus Micropillar Arrays Guides Cell Polarized Migration and Division Cycle

“…In recent years, because of their special asymmetry, asymmetric microstructures have been extensively studied in the field of micro‐ and nanostructures. They have different applications in the field of optics, magnetism, and anisotropic adhesion . Interestingly, the asymmetric micro‐ and nanostructures also cause cell adhesion asymmetry when they are in contact with cells, causing cell‐cytoskeletal polarization and indirectly inducing the generation of different cellular behaviours .…”

Three-color plasmon-mediated reduction of diazonium salts over metasurfaces

“…[1][2][3][4] In discrete nanostructures, LSPRs are generally spatially confined in specific areas and can be excited with selected set of wavelength and polarization of the impinging field. In ideal opto-geometric configuration, the electric field is typically enhanced by a 10-100 fold factor which is enough to yield large enhancement factors and which can in turn be used for a variety of sensing applications through surface enhanced mechanisms in Raman, 2,3,[5][6][7] infrared, [8][9][10] fluorescence, [11][12][13][14] and nonlinear optical measurements. [15][16][17][18] This spatial confinement can also be used to promote chemical reactions through the generation and ejection of hot electrons.…”