Propagating Surface Plasmon Resonance Research Articles

Highly efficient ultra-broadband perfect absorber based on a simple four-layer structure Al–SiO2–Si–Ti in visible to near-infrared region

We propose a highly efficient ultra-broadband perfect absorber with a double-layer continuous spacer of SiO2 and Si based on a simple four-layer structure Al–SiO2–Si–Ti. The absorber shows an average absorption over 98.1% at 780-nm bandwidth from 440 to 1220 nm, where two successive absorption bands are over 99%, and the absorption peak is up to 99.9%. Highly efficient broadband absorption benefits from the surface plasmon resonance (the propagating surface plasmon resonance and the localized surface plasmon resonance). Comparing the absorbers with different spacers, the proposed perfect absorber can be regarded as the superposition of two triple-layer structure absorbers. The absorber exhibits nearly perfect polarization independence and a wide incident angle up to 40 deg for transverse magnetic polarization and transverse electric polarization. In addition, the absorber is not only simple in structure and cheap in Al and Ti materials but also compatible with complementary metal oxide semiconductor technology, which means low cost and high efficiency. We believe that the proposed absorber has tremendous application prospects in areas such as solar energy, optical imaging, and infrared detection.

Wide range refractive index sensor based on a coupled structure of Au nanocubes and Au film

We report a plasmonic refractive index sensor with a wide measurement range based on periodic gold nanocubes coupled with a gold film. The theoretical sensing range is 1.0–1.8. The structure consists of two-dimensional gratings composed of periodic nanocubes that both excite local surface plasmon resonance and stimulate propagating surface plasmon resonance. The strong resonance of the multiple surface plasmons is suitable for use in refractive index sensing and effectively reduces the full width at half maximum of the resonance peak. The sensing performance of each resonant mode in the reflected spectrum is discussed in detail. The highest sensitivity and figure of merit of the proposed sensor are 1002 nm per refractive index units (RIU) and 417 RIU−1, respectively. The proposed sensor will be useful for bio-chemical sensing applications such as measuring changes in the refractive index of gases or liquids.

Experimental studies on the sensitivity of the propagating and localized surface plasmon resonance-based tapered fiber optic refractive index sensors.

In the present study, the sensitivities of the fiber optic propagating surface plasmon resonance (SPR) and localized surface plasmon resonance (LSPR)-based refractive index sensors have been evaluated experimentally for a tapered probe of different taper ratio. The tapering of the fiber probe has been carried out via a heating and stretching technique. The SPR probe has been fabricated by coating a thin film of silver over the core of the tapered optical fiber, while the LSPR probe has been prepared by the coating of the gold nanoparticles over the core of the tapered optical fiber. The increase in the taper ratio increases the sensitivity of both kinds of the probes. The experimentally obtained sensitivity has been compared with the sensitivity of the SPR-based fiber optic refractive index sensors fabricated using various techniques and reported in the literature.

Refractive Index Sensing of Monolayer Molecules Using Both Local and Propagating Surface Plasmons in Mid-Infrared Metagrating

Surface-enhanced infrared absorption spectroscopy (SEIRA) is attractive for molecular sensing due to its high sensitivity and access to molecular fingerprint absorptions. In this paper, we report on refractive index sensing of monolayer molecules in a spectral band outside the molecular fingerprint region. In a metagrating composed of a three-layer metal-insulator-metal structure, both propagating surface plasmon resonances (PSPs) and local surface plasmon resonances (LSPRs) are exited from free-space in a broad band of 3 to 9 µm, and their sensing properties are characterized. In response to a self-assembled monolayer of octadecanethiol (ODT) molecules, both PSPs and LSPRs exhibit redshifts in wavelength. The shifts of LSPRs are larger than those of PSPs, as originated from their stronger spatial confinement and larger field enhancement. Our proposed mid-infrared molecular sensor is immune to frequency variations of plasmon resonance and more tolerant to sample feature size variation.

Localized to Propagating Surface Plasmon Resonance Transition in Ni-Au Magneto-Plasmonic Gratings

Magneto-plasmonic structures, which are the best candidates for different applications, have been the subject of intense research in recent years. In this paper, we proposed new magneto-plasmonic structures based on different uni-dimensional gratings to investigate the localized to propagative surface plasmon resonance transition. For this purpose, simulation of reflectance and also surface plasmon resonance coupling were used in three different fabricated samples compared with nickel thin film under different azimuthaly excitations. The fabricated samples show an enhanced magneto-optical rotation due to the transition of two types of plasmon in the sample with intermediate dimensions. The prospects of magneto-plasmonic response dependency on the azimuthaly excitation are discussed.

Numerical Study of the Wide‐angle Polarization‐Independent Ultra‐Broadband Efficient Selective Solar Absorber in the Entire Solar Spectrum

Increasing the absorption efficiency of solar radiation has great significance for the renewable energy applications, such as residential water heating, seawater desalination, wastewater treatment and solar thermophotovoltaic devices. Optical absorbers based on metamaterials have been widely investigated using a variety of structural designs. However, the near‐ideal solar thermal absorber has not yet been demonstrated, which has a near unity absorption from the ultraviolet to the near‐infrared region and meanwhile an absorption close to zero in the mid‐infrared region. Here, using FEM and FDTD methods respectively, we propose and numerically demonstrate an ultra‐broadband selective solar absorber with an extremely high absorption efficiency above 99% within the range of 435–1520 nm. And meanwhile the emissivity of the nanostructure is below 20% in mid‐infrared region. The total photothermal conversion efficiency of the proposed solar absorber can reach 91.53%, which is very close to the photothermal conversion efficiency (95.6%) of the ideal cut‐off absorber. The physical mechanisms of the nearly perfect absorption are also investigated and analyzed clearly, which is attributed to the hybridization of localized surface plasmon resonance, gap plasmon resonance, and propagating surface plasmon resonance. Particularly, the near‐ideal efficient selective absorption can still be maintained very well at a wide incident angle regardless of the incident light polarization. Owing to the characteristics such as polarization and angle independence, broadband operation, near‐perfect absorption and strong spectral selectivity, the solar absorbers are promising candidates for solar energy harvesting, stealth technology, and thermo‐photovoltaic energy conversion.

Paper-Based Plasmonic Surface for Chemical Biosensing by the Attenuated Total Reflection Method

ABSTRACTWe demonstrate the detection of an increase in refractive index and/or thickness by specific adsorption of proteins on a plasmonic surface on a paper substrate in the Otto configuration. Propagating surface plasmon resonance is observed on a gold surface deposited onto polymer-coated papers through angular scans of reflectivity in the Otto configuration under attenuated total reflection conditions. According to a surface analysis with atomic force microscope, the gold surface roughness on a polyvinyl chloride (PVC)-coated paper is comparable to that of a Si wafer, leading to the achievement of protein detection. On the other hand, the propagating length of the surface plasmons is shorter than that on the Si wafer. According to an observation of the gold surface with scanning electron microscope, the gold grain size on the PVC-coated paper is smaller than that on the Si wafer. Thus, many boundaries cause a reduction in the propagating length on the PVC-coated paper.

Transmission surface plasmon resonance imaging of silver nanoprisms enhanced propagating surface plasmon resonance on a metallic grating structure

The localized surface plasmon resonance of in-plane dipole plasmon resonance of silver nanoprisms was used to facilitate transmission surface plasmon resonance (TSPR). The TSPR signal was detected by a camera coupled with liquid crystal tunable filters. This technique was further utilized for the multiple detection of hydrogen peroxide.

Optical properties of gold nanorods macro-structure: a numerical study

In this contribution, a numerical study of the optical properties of closely-packed gold nanorods was performed. The studied nano-objects are experimentally grown on a tilted polydimethylsiloxane (PDMS) substrate by using physical vapor deposition (PVD). This method creates nanorods tilted to a certain angle with respect to the substrate normal. This geometry allows exciting both transverse and longitudinal modes of the rods. As demonstrated in a previous experimental work, such PVD-grown nano-objects show promising possibilities both as strain gauges or strain-tunable metamaterials if fabricated on a stretchable dielectric substrate. This numerical study is based on experimental data from previous work and pushes further the subject by approaching an optimized nano-structure allowing better strain-sensitivity (particularly by changing the auto-organization of the said nanorods). Full Text: PDF ReferencesJ.W.M. Chon, C. Bullen, P. Zijlstra, M. Gu, "Spectral encoding on Gold Nanorods Doped in a Silica Sol?Gel Matrix and Its Application to High-Density Optical Data Storage", Adv. Funct. Mater. 17, 875 (2007). CrossRef C.-C. Chen, Y.-P. Lin, C.-W. Wang, H.-C. Tzeng, C.-H. Wu, Y.-C. Chen, C.-P. Chen, L.-C. Chen, Y.-C. Wu, "DNA?Gold Nanorod Conjugates for Remote Control of Localized Gene Expression by near Infrared Irradiation", J. Am. Chem. Soc. 128, 3709 (2006). CrossRef J.N. Anker, W.P. Hall, O. Lyandres, N.C. Shah, J. Zhao, R.P. Van Duyne, "Biosensing with plasmonic nanosensors", Nat. Mater 7, 442 (2008). CrossRef B. Sepulveda, P.C. Angelome, L.M. Lechuga, L.M. Liz-Marzan?, "LSPR-based nanobiosensors", Nano Today 4, 244 (2009). CrossRef A. Haes, R.P. Van Duyne, "A Nanoscale Optical Biosensor: Sensitivity and Selectivity of an Approach Based on the Localized Surface Plasmon Resonance Spectroscopy of Triangular Silver Nanoparticles", J. Am. Chem. Soc. 124, 10596 (2002). CrossRef J.C. Riboh, A.J. Haes, A.D. McFarland, C.R. Yonzon, R.P. Van Duyne, "A Nanoscale Optical Biosensor: Real-Time Immunoassay in Physiological Buffer Enabled by Improved Nanoparticle Adhesion", J. Phys. Chem. B 107, 1772 (2003). CrossRef C.R. Yonzon, E. Jeoung, S. Zou, G.C. Schatz, M. Mrksich, R.P. Van Duyne, "A Comparative Analysis of Localized and Propagating Surface Plasmon Resonance Sensors: The Binding of Concanavalin A to a Monosaccharide Functionalized Self-Assembled Monolayer", J. Am. Chem. Soc. 126, 12669 (2004). CrossRef A.J. Haes, L. Chang, W.L. Klein, R.P. Van Duyne, "Detection of a Biomarker for Alzheimer's Disease from Synthetic and Clinical Samples Using a Nanoscale Optical Biosensor", J. Am. Chem. Soc. 127, 2264 (2005). CrossRef R. Caputo, G. Palermo, M.Infusino L. De Sio, "Liquid Crystals as an Active Medium: Novel Possibilities in Plasmonics", Nanospectroscopy 1, 40 (2015). CrossRef T. Maurer, J. Marae-Djouda, U. Cataldi, A. Gontier, G. Montay, Y. Madi, B. Panicaud, D. Macias, P.-M. Adam, G. Lév?que, T. Bürgi, R. Caputo, "The beginnings of plasmomechanics: towards plasmonic strain sensors", Frontiers of Materials Science 9, 170 (2015). CrossRef X. Niu, S. P. Stagon, H. Huang, J.K. Baldwin, A. Misra, "Smallest Metallic Nanorods Using Physical Vapor Deposition", Phys. Rev. Lett. 110 136102 (2013). CrossRef Lumerical Solutions, Inc. DirectLink P.K. Jain, W. Huang, M.A.El-Sayed, "On the Universal Scaling Behavior of the Distance Decay of Plasmon Coupling in Metal Nanoparticle Pairs: A Plasmon Ruler Equation", Nanoletters 7, 2080 (2007). CrossRef P.K. Jain, M.A. El-Sayed, "Plasmonic coupling in noble metal nanostructures", Chem. Phys. Letters 487, 153 (2010). CrossRef

Numerical study of an ultra-broadband near-perfect solar absorber in the visible and near-infrared region.

We propose and numerically investigate a novel ultra-broadband solar absorber by applying iron in a 2D simple metamaterial structure. The proposed structure can achieve the perfect absorption above 95% covering the wavelength range from 400 to 1500nm. The average absorption reaches 97.8% over this wavelength range. The broadband perfect absorption is caused by the excitation of localized surface plasmon resonance and propagating surface plasmon resonance. We first propose and demonstrate that the iron is obviously beneficial to achieve impedance matching between the metamaterial structure and the free space over an ultra-broad frequency band in the visible and near-infrared region, which play an extremely important role to generate an ultra-broadband perfect absorption. In order to further broaden the absorption band, we also demonstrate the perfect absorption exceeding 92% for the 400-2000nm range by adding the number of metal-dielectric pairs and using both gold and iron simultaneously in the proposed structure. The average absorption of the improved absorber reaches 96.4% over the range of 400-2000nm. The metamaterial absorbers using iron are very promising for many applications, which can greatly broaden the perfect absorption band in the solar spectrum and, meanwhile, can enormously reduce the cost in the actual production.

Au-Graphene Hybrid Plasmonic Nanostructure Sensor Based on Intensity Shift.

Integrating plasmonic materials, like gold with a two-dimensional material (e.g., graphene) enhances the light-material interaction and, hence, plasmonic properties of the metallic nanostructure. A localized surface plasmon resonance sensor is an effective platform for biomarker detection. They offer a better bulk surface (local) sensitivity than a regular surface plasmon resonance (SPR) sensor; however, they suffer from a lower figure of merit compared to that one in a propagating surface plasmon resonance sensors. In this work, a decorated multilayer graphene film with an Au nanostructures was proposed as a liquid sensor. The results showed a significant improvement in the figure of merit compared with other reported localized surface plasmon resonance sensors. The maximum figure of merit and intensity sensitivity of 240 and 55 RIU−1 (refractive index unit) at refractive index change of 0.001 were achieved which indicate the capability of the proposed sensor to detect a small change in concentration of liquids in the ng/mL level which is essential in early-stage cancer disease detection.

Gold-Graphene Core-Shell Nanostructure Surface Plasmon Sensors

Localized surface plasmon resonance sensors in nanostructures have wide applications from medical diagnostics to environmental monitoring. The quality and performance of a sensor is normally assessed by its sensitivity and figure of merit (FOM). Generally, localized surface plasmon sensors suffer low FOM due to strong radiative damping of localized surface plasmon and hence broad resonance peaks compared to that one in propagating surface plasmon resonance sensors. In this work, a 2D array of gold-graphene spherical core-shell nanostructure on a quartz substrate was introduced as a liquid sensor with FOM and sensitivity as large as 102.6 and 350 nm/RIU, respectively, in a gold-graphene hybrid nanostructure. The results showed a significant improvement in the FOM compared to previous works and common surface plasmon resonance refractive index surface plasmon sensors such as nanohole arrays.

Plasmon-Electrical Effects on Organic Solar Cells by Incorporation of Metal Nanostructures

Recently, plasmonic effects of metal nanostructures have been intensively exploited to enhance the performance of organic solar cells (OSCs). The plasmonic-optical effects of localized surface plasmon resonances, scattering effect and propagating surface plasmon resonances, etc., are well recognized in considerably enhancing the active layer absorption. Besides, the improved electrical properties of OSCs by plasmonic-electrical effects have recently been reported to be of equal importance in enhancing the performance of OSCs through the introduction of plasmonic metal nanostructures into different layers of OSCs. In this review, the plasmonic-electrical effects of metal nanostructures-induced space-charge limit elimination, transfer of plasmonically excited hot carriers, and charge-accumulation effects would be briefly discussed. The mechanisms of each plasmonic-electrical effect including tailored transport path of charge carriers (electron and hole), reduced extraction barrier of carrier transport layer, and redistributed exciton generation in active layer for enhancing the performance of OSCs would also be studied simultaneously with the experimental and theoretical results. The promoted electrical properties of OSCs by the plasmonic-electrical effects and the future combination of plasmonic-optical and electrical effects would promisingly offer an alternative way to further improve the performance of OSCs.

Localized and propagating surface plasmon resonances in aperture-based third harmonic generation.

We investigate the influence of localized and propagating surface plasmons on third harmonic generation from rectangular apertures in metal films. We designed optimal aperture array structures by using finite-difference time-domain simulations with nonlinear scattering theory. From this design space, we fabricated and measured the third harmonic in the region of maximal performance. We find the highest third harmonic conversion efficiency when the localized resonance is tuned to the fundamental wavelength and the propagating (Bragg) resonance is tuned to the third harmonic; this is 2.5 times larger than the case where the both localized and propagating are tuned to the fundamental wavelength. The two remaining configurations where also investigated with much lower conversion efficiency. When the Bragg resonance is tuned to the third harmonic, directivity improves the collection of third harmonic emission. On the other hand, due to the inherent absorption of gold at the third harmonic, tuning the localized surface plasmon resonance to the third harmonic is less beneficial. All cases showed quantitative agreement with the original theoretical analysis. This work points towards an optimal design criterion for harmonic generation from thin plasmonic metasurfaces.

Extraordinary terahertz transmission through a copper film perforated with circular and rectangular apertures

The extraordinary transmission (ET) due to localized surface plasmon (LSP) and propagating surface plasmon (PSP) resonances of terahertz wave through a copper film perforated with circular and rectangular apertures is investigated theoretically and experimentally. Considering that the field distributions of LSP and PSP resonances are determined by the shape and periods of the apertures on the film, the relations between extraordinary and the geometrical parameters of the apertures are investigated. The intensities of the ETs induced by the PSP resonances mode [1, 1] are much stronger than the fundamental ones [1, 0] and [0, 1]. Our finds provide another effective method to tailor the extraordinary THz transmission in sub-wavelength metallic aperture structures.

Loop-Turn Optical Flows with Spectral Selectivity in Suspended Plasmonic Nanofin-Cavity Structure

Metallic nanostructures sustain surface plasmons that strongly couple incident light to the surface of the metal. They have received a great amount of attention as a possible means of light manipulation. Among the various reported structures, cavities are promising for spectroscopic applications because the cavity mode, with its narrow band, large modulation, and tunability over a wide range of wavelengths, provides a means to improve the resonances in far-field measurements. This report describes a suspended plasmonic nanofin-cavity structure capable of producing tunable reflected resonances with high quality factors (Q) in the infrared (IR) region. The nanofin-cavity structure having plasmonic hot spots on the ridges supports standing-wave resonances with enhanced electric fields in the horizontal and vertical directions; strong optical flows are thus generated and light turns in a loop, resulting in high reflectance. When the nanofin cavity is further coupled to the propagating surface plasmon resonance (SPR), a strong and narrow-band reflectance resonance due to the stringent condition of SPR arises with a bandwidth having a full width at half-maximum (FWHM) of 92 nm and a Q as large as 60. Furthermore, as result of the coupled modes, the intensity of the resonance peak depends on the angle of the incident light and thus presents a potential means of angle-controlled optical switching in the IR region. Finally, high-order modes of a nanofin-cavity structure were observed in the near-infrared (NIR) region for which wavelengths are much shorter than the cavity scale, thus, demonstrating the possibility of easing the difficulty of fabrication.

Enhanced nonreciprocal effects in magnetoplasmonic systems supporting simultaneously localized and propagating plasmons.

Perforated magnetoplasmonic Au/Co/Au multilayers support both localized and propagating surface plasmon resonances. The presence of holes produces an enhancement of the magnetic field modulation of the propagating surface plasmon wavevector with respect to the isostructural continuous film in the spectral region corresponding to the hole associated localized plasmon resonance. This is due to the increased electromagnetic field in the surrounding area of the resonant hole, and the subsequent additional contribution to the magnetic modulation of the continuous film. This novel concept that gives rise to enhanced magnetic field induced nonreciprocal effects can be of interest in the development of innovative platforms for sensing applications, optical isolators and modulators.

Localized and propagating surface plasmon resonance based fiber optic sensor for the detection of tetracycline using molecular imprinting

In the present study we report a novel approach for the fabrication of localized and propagating surface plasmon resonance based fiber optic sensor for the detection of tetracycline using molecular imprinting (MIP) technique. The sensor is fabricated by coating layers of silver film, silver nanoparticles and MIP film prepared using tetracycline molecule as template over an unclad core of the multimode optical fiber. Nanoparticles of sizes in the range 10–30 nm are synthesized by hydrothermal process. A polychromatic light source is used to launch the light from one end of the fiber and the absorption spectrum for a given concentration of the tetracycline solution around the probe is measured at the other end of the fiber using a spectrometer interfaced with a computer. The absorption spectra are recorded for the concentration range of tetracycline from 10−8 M to 10−5 M. A shift of 102 nm in peak absorbance wavelength is obtained for this concentration range. The sensor works in the promising concentration range of tetracycline found in foods etc. The sensor has various advantages such as high sensitivity, low cost, fast response and capability of online monitoring and remote sensing. Further, the sensitivity of the sensor is about double the sensor based on localized surface plasmon resonance and molecular imprinting.

Biosensors Based on Plasmonics

Because of the sensitivity to refractive index changes, plasmonics nanostructures have been investigated broadly for the bio-molecules detection through the excitations of the propagating surface plasmon resonance (PSPR) or localized surface plasmon resonance (LSPR). PSPR sensors can detect sub-monolayer quantities of bio-molecules at the gold film surface and provide real-time data through continuous optical measurements. LSPR sensors could be more sensitive to local refractive index changes and the factors of nanoparticle material, shape and size are all interrelated and contribute to the refractive index sensitivities.

Plasmonic biosensors.

The unique optical properties of plasmon resonant nanostructures enable exploration of nanoscale environments using relatively simple optical characterization techniques. For this reason, the field of plasmonics continues to garner the attention of the biosensing community. Biosensors based on propagating surface plasmon resonances (SPRs) in films are the most well-recognized plasmonic biosensors, but there is great potential for the new, developing technologies to surpass the robustness and popularity of film-based SPR sensing. This review surveys the current plasmonic biosensor landscape with emphasis on the basic operating principles of each plasmonic sensing technique and the practical considerations when developing a sensing platform with the various techniques. The 'gold standard' film SPR technique is reviewed briefly, but special emphasis is devoted to the up-and-coming localized surface plasmon resonance and plasmonically coupled sensor technology.