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Asymmetric Split-H Based Metasurfaces for Identification of Organic Molecules
Published in Pankaj K. Choudhury, Metamaterials, 2021
Ili F. Mohamad Ali, Ifeoma G. Mbomson, Marc Sorel, Nigel P. Johnson, Caroline Gauchotte-Lindsay, Richard M. De La Rue
A plasmonic metamaterial is one that, through interaction with electromagnetic radiation, produces artificial optical properties based on surface plasmon effects. The resonant oscillation of free electron gas in metals formed by the interactions of incident light with dielectrics and metals, known as surface plasmon resonance, is currently being used widely for biosensor applications. Sensing applications benefit from the tunability features of plasmonic resonance produced in the many metamaterials used for various vibrational modes in the region of IR spectroscopy [1–8]. The term metasurface is now widely used for metamaterials that are created as metallic patterns on the surface of substrates via the lithographic processes that are typical of planar fabrication technology. There are many molecular vibrations that occur in the mid-IR spectral region [9].
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Published in Chad A. Mirkin, Spherical Nucleic Acids, 2020
Matthew R. Jones, Kevin L. Kohlstedt, Matthew N. O’Brien, Jinsong Wu, George C. Schatz, Chad A. Mirkina
The physical properties of matter rely fundamentally on the symmetry of constituent building blocks. This is particularly true for structures that interact with light via the collective motion of their conduction electrons (i.e., plasmonic materials), where the observation of exotic optical effects, such as negative refraction and electromagnetically induced transparency, require the coupling of modes that are only present in systems with nontrivial broken symmetries. Lithography has been the predominant fabrication technique for constructing plasmonic metamaterials, as it can be used to form patterns of arbitrary complexity, including those with broken symmetry. Here, we show that low-symmetry, 1D plasmonic structures that would be challenging to make using traditional lithographic techniques can be assembled using DNA as a programmable surface ligand. We investigate the optical properties that arise as a result of systematic symmetry breaking and demonstrate the appearance of π-type coupled modes formed from both dipole and quadrupole nanoparticle sources. These results demonstrate the power of DNA assembly for generating unusual structures that exhibit both fundamentally insightful and technologically important optical properties.
Nanoplasmonic optoelectronics
Published in John P. Dakin, Robert G. W. Brown, Handbook of Optoelectronics, 2017
A key step to volume production of practical nanoplasmonic optoelectronic structures will be to develop the above and other fabrication techniques to cover large areas, perhaps on many different kinds of substrate materials, e.g., Si, GaAs, GaP, etc. One promising approach, currently with some fundamental reproduction precision challenges, is that of nanoimprinting. Soft nanoimprint lithography has demonstrated defect-free arrays of nanowires over 2-in. wafer substrates (Pierret et al., 2010). Single-layer and multilayer plasmonic metamaterials have been fabricated by production-capable nanoimprint lithography (Bergmair et al., 2011). Sub-10-nm patterns have been demonstrated with step-and-repeat nanoimprinting (Peroz et al., 2012), and sub-100-nm metal nanodot arrays have been created using nanostamping (Lee et al., 2011a). Optical force stamping has also been employed (Nedev et al., 2011), for creating arbitrary patterns of colloidal nanoparticles. Large-area “nanocoining” has been used to create millions of nanostructures per second over hundreds of square millimeters (Zdanowicz et al., 2012). 3D large-area negative-index metamaterials have also been created by nanotransfer printing (Chanda et al., 2011).
Multipole resonances-mediated dual-band tunable circular dichroism via vanadium dioxide chiral metamaterials
Published in Waves in Random and Complex Media, 2023
Shi Li, Tian Sang, Chaoyu Yang, Chui Pian, Yueke Wang, Bolun Hu, Cheng Liu
As a typical artificial metamaterial, plasmonic metamaterial exhibits unique and special abilities related to electromagnetic wave control, including strong field localization in the vicinity of the surfaces, which can upgrade the intensity of light-matter interactions and can enhance the chiroptical responses [8–10]. Plasmonic chiral metamaterials have been shown to enable numerous optical applications via the design and tailoring of their subunit building blocks such as plasmonic chiral metamaterial absorbers [11], chiral optofluidics [12], chiral coding [13,14], and photodetection [15]. However, the functions of the traditional plasmonic chiral metamaterials are fixed once being fabricated [16–19], and dynamical controls of chiral responses for versatile applications such as switching or tuning functions are highly desired.
High-efficiency broadband polarisation converter via patterned multilayer twisted liquid crystal polymer
Published in Liquid Crystals, 2023
Shang Liu, Tibin Zeng, Jin Xie, Yingjie Zhou, Xiangyu Jiang, Xianglin Ye, Fan Fan, Shuangchun Wen
So far, 3M’s broadband reflective polariser has become the most used commercial product due to the significant improvement in the recycling efficiency of the display system achieved by reflection, and its outstanding performance in bandwidth and acceptance angle [12]. In recent years, benefiting from the advancement of nanofabrication technologies, ultra-thin optics represented by metasurfaces have gradually emerged [13–15]. Polarisation conversion could be achieved by designing specific periodic nanostructures with subwavelength unit. For instance, an ultra-high-efficiency linear polariser based upon an all-dielectric metamaterial patterned at subwavelength dimension has been proposed [14]. Additionally, a planar-helix chiral metamaterial is employed to expand bandwidth while maintaining high circular polarisation selection efficiency [15]. There are some factors such as limited size and high cost preventing the extensive use of plasmonic metamaterial and metasurface. Moreover, the performance of these polarisers may well degrade with a change in incident angle because exquisite nanostructures are only optimised for efficiency without considering possible oblique incidence. Juggling efficiency, bandwidth and incident angle all at the same time will inevitably bring greater challenges to design and fabrication of device structures, but LC may tackle these challenges well with the development of alignment technology. LC materials have been massively found in current optical components including the LC display and remote sensing applications due to its fascinating birefringent property and electrically dynamic optic-electric tunability [16–27]. For instance, taking advantage of LC retardation compensation, remarkable achromatic PG and retarders employing twisted structure have been reported [16–21], and the team has also proposed fantastic polarisation conversion systems, which manifests excellent performance in terms of efficiency, angle tolerance and bandwidth [24,25]. Besides, complex nanoscale-ordered LC polymer film is developed to realise holographic polariser, which demonstrates high transmittance but with a limited operating bandwidth [26]. Overall, planar LC optical devices with sophisticated structures have been endowed with prominent advantages in terms of manufacturing difficulty and weight, providing us a whole new perspective for designing the multifunctional integrated optical system.