Plasmonic Perfect Absorber Research Articles

Tunable near-infrared plasmonic perfect absorber based on phase-change materials

A tunable plasmonic perfect absorber with a tuning range of similar to 650 nm is realized by introducing a 20 nm thick phase-change material Ge2Sb2Te5 layer into the metal-dielectric-metal configuration. The absorption at the plasmonic resonance is kept above 0.96 across the whole tuning range. In this work we study this extraordinary optical response numerically and reveal the geometric conditions which support this phenomenon. This work shows a promising route to achieve tunable plasmonic devices for multi-band optical modulation, communication, and thermal imaging. (C) 2015 Chinese Laser Press

Tunable enhanced optical absorption of graphene using plasmonic perfect absorbers

Enhancement and manipulation of light absorption in graphene is a significant issue for applications of graphene-based optoelectronic devices. In order to achieve this purpose in the visible region, we demonstrate a design of a graphene optical absorber inspired by metal-dielectric-metal metamaterial for perfect absorption of electromagnetic waves. The optical absorbance ratios of single and three atomic layer graphene are enhanced up to 37.5% and 64.8%, respectively. The graphene absorber shows polarization-dependence and tolerates a wide range of incident angles. Furthermore, the peak position and bandwidth of graphene absorption spectra are tunable in a wide wavelength range through a specific structural configuration. These results imply that graphene in combination with plasmonic perfect absorbers have a promising potential for developing advanced nanophotonic devices.

High‐Color‐Purity Subtractive Color Filters with a Wide Viewing Angle Based on Plasmonic Perfect Absorbers

High‐Color‐Purity Subtractive Color Filters with a Wide Viewing Angle Based on Plasmonic Perfect Absorbers

Large‐Area Low‐Cost Tunable Plasmonic Perfect Absorber in the Near Infrared by Colloidal Etching Lithography

Optical elements with absorbance close to unity are of crucial importance for diverse applications, ranging from thermal imaging to sensitive trace gas detection. A key factor for the performance of such devices is the need for absorbance with high acceptance angles, which are able to utilize all incident radiation from the forward‐facing half‐space. Here, a tunable, angle‐, and polarization independent large‐area perfect absorber is reported, which is fabricated by a combination of colloidal lithography and dry‐etching. This design is easy and fast to produce, and low‐cost compared with other common methods. Variation of the dry‐etching time shifts the resonance from almost 825 to 1025 nm with reflection smaller than 3% and zero transmission. Due to the inherent disordered arrangement, this design is fully polarization independent and the absorbance remains higher than 98% for incident angles up to 50°.

C122 金属-絶縁体-金属構造を用いた高温波長選択熱輻射体の作製と評価(OS-06:ふく射輸送制御(2))

We have fabricated metal-insulator-metal (MIM) structures, which is so-called plasmonic perfect absorber. For high temperature application, molybdenum which is a refractory metal and aluminum oxide were used as the metal layer and the insulator layer, respectively. The top Mo layer is composed of disk array structure, obtained by means of colloidal lithography and reactive ion etching. The absorption peak of the structure was narrow-band and could be successfully tuned in the mid-infrared range. The emission properties at high temperature were also evaluated. The MIM structures showed good thermal stability at high temperature up to 800℃ and thus can act as a high temperature wavelength-selective thermal emitter.

Quantitative Angle-Resolved Small-Spot Reflectance Measurements on Plasmonic Perfect Absorbers: Impedance Matching and Disorder Effects

Plasmonic devices with absorbance close to unity have emerged as essential building blocks for a multitude of technological applications ranging from trace gas detection to infrared imaging. A crucial requirement for such elements is the angle independence of the absorptive performance. In this work, we develop theoretically and verify experimentally a quantitative model for the angular behavior of plasmonic perfect absorber structures based on an optical impedance matching picture. To achieve this, we utilize a simple and elegant k-space measurement technique to record quantitative angle-resolved reflectance measurements on various perfect absorber structures. Particularly, this method allows quantitative reflectance measurements on samples where only small areas have been nanostructured, for example, by electron-beam lithography. Combining these results with extensive numerical modeling, we find that matching of both the real and imaginary parts of the optical impedance is crucial to obtain perfect absorption over a large angular range. Furthermore, we successfully apply our model to the angular dispersion of perfect absorber geometries with disordered plasmonic elements as a favorable alternative to current array-based designs.

Plasmonic Perfect Absorbers for Biosensing Applications

We present a theoretical modal investigation of plasmonic perfect absorbers (PPAs) based on the localized surface plasmon resonance (LSPR) for biosensing applications. We design the PPA geometry with a layer of periodic metallic nanoparticles on one side of a dielectric substrate and a single metallic layer on the opposite side. The electromagnetic (EM) fields confine partly in the surrounding medium above the substrate and within the substrate itself. We examine the modes of the PPA geometry for a wavelength range of 600–1500 nm. The fundamental mode of the system provides perfect absorption for a wide angle of incidence 0–70°. The second-order mode shows a strong angular dependence with a sharp resonance and exhibits perfect optical absorption when the critical coupling condition for LSPR is achieved. The coupling condition depends on the size, periodicity, dielectric spacer, and the surrounding material of the system. The strong dependence on the surrounding material makes it a promising candidate for biosensing applications. We introduce a novel approach to investigate the angular dependence of the refractive index change for the PPA system. This novel technique contributes the significant attributes of the LSPR sensors, can be used for any required resonance wavelength depending on geometric design, and it also provides sensitivity analogous to the standard surface plasmon resonance (SPR) biosensors.

Enhancing intensity and refractive index sensing capability with infrared plasmonic perfect absorbers.

An infrared refractive index sensor based on plasmonic perfect absorbers for glucose concentration sensing is experimentally demonstrated. Utilizing substantial absorption contrast between a perfect absorber (∼98% at normal incidence) and a non-perfect absorber upon the refractive index change, a maximum value of figure of merit (FOM*) about 55 and a bulk wavelength sensitivity about 590 nm/RIU are achieved. The demonstrated sensing platform provides great potential in improving the performance of plasmonic refractive index sensors and developing future surface enhanced infrared spectroscopy.

Plasmonic nanoantennas as integrated coherent perfect absorbers on SOI waveguides for modulators and all-optical switches

The performance of plasmonic nanoantenna structures on top of SOI wire waveguides as coherent perfect absorbers for modulators and all-optical switches is explored. The absorption, scattering, reflection and transmission spectra of gold and aluminum nanoantenna-loaded waveguides were calculated by means of 3D finite-difference time-domain simulations for single waves propagating along the waveguide, as well as for standing wave scenarios composed from two counterpropagating waves. The investigated configurations showed losses of roughly 1% and extinction ratios greater than 25 dB for modulator and switching applications, as well as plasmon effects such as strong field enhancement and localization in the nanoantenna region. The proposed plasmonic coherent perfect absorbers can be utilized for ultracompact all-optical switches in coherent networks as well as modulators and can find applications in sensing or in increasing nonlinear effects.

Tunable broadband plasmonic perfect absorber at visible frequency

Metamaterials and plasmonics as a new pioneering field in photonics joins the features of photonics and electronics by coupling photons to conduction electrons of a metal as surface plasmons (SP). This concept has been implemented for a variety of applications including negative index of refraction, magnetism at visible frequency, cloaking devices amongst others. In the present work, we used plasmonic hybrid material in order to design and fabricate a broad-band perfect plasmonic metamaterial absorber in a stack of metal and Copper-PTFE (Polytetrafluoroethylene) nanocomposite showing an average absorbance of 97.5 % in the whole visible spectrum. Our experimental results showed that the absorption peak of the stacks can be tuned upon varying the thickness and type of the spacer layer due to the sensitivity of plasmon resonance to its environment. To the best of our knowledge, this is the first report of a plasmonic metamaterial absorber based on copper with absorption around 100 % in the entire visible and near-Infrared (NIR).

Tunable wide-angle plasmonic perfect absorber at visible frequencies

We report a perfect absorber metallic hole array with wide-angle near unity absorbance in the visible regime. The periodicity of the structure enables excitation of surface-plasmon polaritons and results in a splitting of the absorbing peaks. An analytical formalism based on perturbation theory provides results in good agreement with experimental data and shows how the absorption peak can be tuned with hole geometry, periodicity, and material parameters. Being extendable to more complex hybrid structures, our result is important for the development of photon harvesting devices and thermal emitters.

Light-driven tunable dual-band plasmonic absorber using liquid-crystal-coated asymmetric nanodisk array

We experimentally demonstrated a light-driven reconfigurable near perfect plasmonic absorber working at dual frequencies in infrared range. By employing nanodisks with different sizes in certain arrangement, near perfect absorption of incident electromagnetic waves can be achieved for different working frequencies due to the resonance between the incident light and the nanodisk of different sizes. We showed that optically induced changes in the dielectric constant of the adjacent liquid crystal layer is an effective means to tune the absorption bands of an asymmetric gold nanodisk array. Our liquid crystal based infrared plasmonic absorber can be tuned by using visible light in real time. A tunable range of 25 nm has been confirmed by both simulation and experiment.

Design of a Perfect Black Absorber at Visible Frequencies Using Plasmonic Metamaterials

The design and fabrication of a plasmonic black absorber with almost 100% absorbance spanning a broad range of frequencies from ultraviolet (UV) to the near infrared (NIR) is demonstrated. The perfect plasmonic absorber is achieved by a combination of a metal film with suitable metal/dielectric nanocomposites. Our fabrication technique is simple, versatile, cost-effective, and compatible with current industrial methods for solar absorber production.

Palladium-Based Plasmonic Perfect Absorber in the Visible Wavelength Range and Its Application to Hydrogen Sensing

We report on the experimental realization of a palladium-based plasmonic perfect absorber at visible wavelengths and its application to hydrogen sensing. Our design exhibits a reflectance <0.5% and zero transmittance at 650 nm and the operation wavelength of the absorber can be tuned by varying its structural parameters. Exposure to hydrogen gas causes a rapid and reversible increase in reflectance on a time scale of seconds. This pronounced response introduces a novel optical hydrogen detection scheme with very high values of the relative intensity response.

Infrared Perfect Absorber and Its Application As Plasmonic Sensor

We experimentally demonstrate a perfect plasmonic absorber at lambda = 1.6 microm. Its polarization-independent absorbance is 99% at normal incidence and remains very high over a wide angular range of incidence around +/-80 degrees. We introduce a novel concept to utilize this perfect absorber as plasmonic sensor for refractive index sensing. This sensing strategy offers great potential to maintain the performance of localized surface plasmon sensors even in nonlaboratory environments due to its simple and robust measurement scheme.