Internal Reflection Configuration Research Articles

Experimental assessment of the effective-medium approach for disordered monolayers of particles with high scattering losses.

The validity of using an effective-medium approach (EMA) to model the reflectivity of a disordered monolayer of particles that scatter light significantly is tested experimentally. To achieve this, we measured the optical reflectivity versus the angle of incidence in an internal reflection configuration of a disordered monolayer of polymeric particles with negligible optical absorption and a diameter of about half a wavelength (size parameter of 1.2) deposited on a glass-air interface. We found a clear effective-medium film equivalence, even for low particle densities and for angles of incidence well beyond the critical angle, where light penetrates the monolayer less than a particle diameter.

Seismic stratigraphy and structural analysis in the determination of petroleum play within Salin basin, Myanmar

<p>This study presents a new interpretation of the seismic stratigraphic unit equivalent to the Late Cretaceous to Pliocene formations in the Salin basin. Many researchers investigated the outcrops of the stratigraphic succession of the Salin basin but there is a lack of comprehensive analysis by seismic interpretation. This study provides a comprehensive description of the structural development within the Salin basin, enhancing our comprehension of the regional stratigraphic evolution of the examined region. Seismic sequences were delineated using a combination of horizon mapping, internal reflection configuration, termination patterns, and thickness analysis. We identified two distinct mechanisms for lateral fault seals: (1) primary juxtaposition seals and (2) secondary fault rock seals (also known as membrane seals). Once the hydrocarbons are matured within the source formations (Late Cretaceous to Early Oligocene shales units): Kabaw (KB); Laungshe (LA); Tabyin (TA); Pondaung (PO); Yaw (YA); and Shwezettaw (SZT), they are migrated towards the reservoir formations (Pondaung (PO), Shwezettaw (SZT), Padaung (PA), Okhmintaung (OHK), and Kyaukkok (KK)) through these predicted paths. Generally, the primary migration takes place along the fault or fractured planes or pores within rock units. In the southwestern limb of the Yenangyaung anticline, the disharmonic folding and upward bending of the KK, PY, OHK, and PA formations resulted in the deformation of ductile strata within the PA Formation, forcing them towards the peripheral synclines. The main deep fore-thrust in the southwestern limb of the Chauk anticline rooted within the PA Formation flattened up while approaching the OHK and PY formations. Chauk anticlinal axis above the PY and OHK detachment level are more migrated toward the northeast. As a result, above the crest of the deep anticline, the shallow low-angle fore-thrust pushed up into the growth strata, leading to the uplift of the YA and SZT formations within the Letpando anticline. YA Formation crops out locally along the axis of the structure and is the major seal, with sandstones in the underlying Eocene PO Formation being the main reservoir.</p>

A Highly Sensitive and Specific Photonic Crystal-Based Opioid Sensor with Rapid Regeneration.

Opioid misuse and overdose have caused devastating public health challenges and economic burdens, calling for the need of rapid, accurate sensitive opioid sensors. Here, we report a photonic crystal-based opioid sensor in the total internal reflection configuration, providing label-free, rapid, quantitative measurements through change of the refractive index. The one-dimensional photonic crystal with a defect layer that is immobilized with opioid antibodies acts as a resonator with an open microcavity. The highly accessible structure responds to analytes within a minute after the aqueous opioid solution is introduced, achieving the highest sensitivity of 5688.8 nm/refractive index unit (RIU) at the incident angle of 63.03°. Our sensor shows a limit of detection (LOD) of 7 ng/mL for morphine in phosphate-buffered saline (PBS, pH 7.4) solutions, well below the required clinical detection limit, and an LOD of 6 ng/mL for fentanyl in PBS, close to the clinical requirement. The sensor can selectively detect fentanyl from a mixture of morphine and fentanyl and be regenerated in 2 min with up to 93.66% recovery rate after five cycles. The efficacy of our sensor is further validated in artificial interstitial fluid and human urine samples.

Reading the sediment archive of the Eastern Campeche Bank (southern Gulf of Mexico): from the aftermath of the Chicxulub impact to Loop Current variability

This is the first high-resolution seismic study showing how the Chicxulub impact shaped the eastern slope of the Campeche Bank in the south-eastern Gulf of Mexico. The induced shock wave fractured Cretaceous strata causing the collapse of the upper slope and shelf over a length of ca. 200 km. Failed material was either transported downslope or remained in parts on the accommodation space created by the collapsed. In the Cenozoic, the East Campeche Plastered Drift developed within the created accommodation space, controlled by the inflowing surface current from the Caribbean, which forms the Loop Current. The internal reflection configuration of the drift shows that the closure of the Suwannee Strait in the Late Oligocene and the closure of the CAS in the Mid to Late Miocene controlled the variability of the southern Loop Current in time. Since the Loop Current transports heat and moisture from the western Atlantic warm water pool into the North Atlantic and further to NW Europe by the Gulf Stream, the drift represents an archive for controlling factors that influenced climate of the northern hemisphere. This first high-resolution seismic reflection study from the eastern Campeche Bank expands the understanding of destructive processes that a meteorite impact induces into the earth system. Furthermore, these data document that the East Campeche Plastered Drift bears the potential to understand the link between the climate variability of the northern hemisphere and oceanic processes in the equatorial western Atlantic.

Resolution enhancement using a multi-layered aluminum-based plasmonic device for chikungunya virus detection

Biomolecular variations can be accounted for by changes in the intrinsic properties of the surrounding medium, such as the refractive index. This work employs such an arrangement using a modified attenuated total internal reflection configuration for telecommunication wavelength (1550 nm). The phenomenon of surface plasmon resonance is initiated by Aluminum (Al) metal due to its low cost and better compatibility with CMOS devices. To achieve improved plasmonic response in terms of the sensor’s resolution, we have explored metal-dielectric-metal configuration under angle interrogation. Barium titanate and Molybdenum disulfide (MoS2) have been employed as the high dielectric constant material and the binding media respectively to enhance the sensing performance. After a series of optimizations, the proposed device configuration leads to a maximum Figure of Merit (FOM) of 540.9 RIU− 1, thus enhancing the resolution. The proposed plasmonic device can be used for chikungunya virus detection by considering different blood components in normal and infected stages. This Al-based multi-layered plasmonic device can serve many applications for resolution enhancement in the near-infrared region.

Influence of wetting behavior on the morphology of droplet impacts onto dry-patterned micro-structured surfaces

The influence of surface roughness, especially regularly patterned micro-structures on the physical outcomes of droplet impacts, is far from fully understood. In order to get a deeper insight into the physics of the impact phenomena, a systematic experimental study of the morphology on regularly patterned micro-structured surfaces has been carried out. The used structures with different dimensions were grooves and pillars with a square cross section. With the help of plasma activation and plasma polymerization processes, the surface wettability was modified independently from the surface structure and material. Two different test fluids were used, namely, distilled water and isopropanol, impacting with various impact energies onto the patterned surface samples. For a better characterization of the impact process, high-speed images from three different perspectives have been acquired synchronously. Due to the transparent surface material, the bottom perspective using a total internal reflection configuration was able to visualize air entrapment inside the surface structure. To the authors' knowledge, such images are not available in the literature, yet. The outcomes have been qualitatively investigated, summarized, and compared. A dependency of the outcomes on the impact energy, the surface wettability, and the structure dimensions could be clearly shown. In general, increasing impact energy will promote the tendency of splashing. However, roughness features cannot only trigger splashing, but can also inhibit it, for example, crown splashing. Moreover, reproducible arrangements of air entrapment inside the structure could be found, which was addressed by the authors as “cookie” and “button” due to their appearance.

Sub-bottom and bathymetry sonar inspection of postglacial lacustrine infill of the alpine lakes (Tatra Mts., Slovakia)

An acoustic survey using sub-bottom sonar (SBS) and Autonomous Underwater Vehicle EcoMapper (AUVEM) combined with coring was used for the investigation of bottom topography, thickness of the sediments, and geodynamic factors influencing the postglacial deposition in Tatra Mts. lakes. This combined study of seven lakes shows four basic acoustic units and four subunits that are interpreted in terms of stratigraphy and lithology.However, the presence of particular acoustic units may not be encountered in all the lakes due to the effects of local and internal lake processes. Thick horizontal reflections with high amplitude reflectors characterize the bedrock or the infill with a thickness of more than 6 m. Chaotic internal reflection configuration and high amplitude reflectors are common and reflect the glacigene deposits of unknown thickness in the bottom of the lakes. Above the signals of glacigene sediments lie reflections with weak to moderate amplitude reflectors, and with a parallel and chaotic configuration. They correspond to the glaciolacustrine laminated clay and silt and postglacial gyttja that contain clastic outwash from various mass movement deposits. The transition zone between these two SBS reflections is formed by a discontinuous, parallel and wavy configuration with the acoustic bottom. This type of signal is interpreted as a mixture of cobbles, boulders, and fine-grained sediments.The exact lithological content and the presence of the acoustic units are determined by other factors that may not be visible around the lakes and can cause stratigraphic hiatuses. As a prominent and un-recognized factor in the Tatra Mts. until now is the presence of the bottom springs (pockmarks) of the non-karstic origin, which effectively disturb the fine clastic and organic matter deposition and hence can limit the use of the lake deposit for palaeoclimatic and palaeoecological studies. The mass movement processes – debris flow, rockfall – forming the mountain geo-relief are frequent and their products are visible in the marginal facies. The sonar inspection also provides evidence of mass movement deposits, which have no indication on the terrestrial environment and thereby represent intralacustrine landslides as a result of bedrock instability due to the late Pleistocene deglaciation or Holocene climatic variability.

Probing bio-tissue films by optical internal reflectivity: modeling and measurements.

In this paper, we develop a detailed theoretical model for the optical reflectivity of a bio-tissue film confined between two flat interfaces based on the anomalous-diffraction approximation. We consider bio-tissue films consisting of a few layers of spheroidal cells surrounded by extracellular medium. We explore numerically the predictions of our model and compare them with simple effective medium theories, sometimes used as a first attempt to understand the optical properties of biological media. Then, we fit the model to experimental reflectivity-versus-angle-of-incidence curves of confined whole-blood films measured in an internal reflection configuration. Measurements were performed by confining a drop of fresh blood between a prism and a coverslip. Our experimental results show that it is possible to measure the coherent reflectance with small enough error to infer microstructural parameters with a good precision. The errors in measuring the coherent reflectance depend on the reflectivity magnitude. For instance, for a reflectivity of about 0.3 the error is below 2%, and the refractive indices of cells and surrounding medium can be obtained with a precision better than 1%. These results also indicate that the present model can readily be used to figure out the physical changes experienced at the microscale in bio-tissue films during a physicochemical process.

Patterning of transition metal dichalcogenides catalyzed by surface plasmons with atomic precision

Summary Plasmon-induced charge transfer has drawn considerable interests and spurred rapid developments of photovoltaics and photocatalysis. Various plasmonic metal/transition metal dichalcogenide (TMD) heterostructures have been developed to promote charge separation. For plasmon-induced catalysis, the transformation of TMDs is rare, and the erosion of TMDs has not yet been reported. Here, we report the etching of two-dimensional TMDs by planar surface plasmon polaritons (SPPs). We found that SPPs can etch various TMDs into desired layers and lateral size through controlling the light power and incident direction. In aqueous media, the strong plasmonic coupling at Au/MoS2 interface generates holes in the valence band of MoS2 that can weaken its interlayer interaction. As a synergistic effect, the plasmonic hot electrons produce oxidizing H2O2 to dissolve MoS2 from the top layers. Our results provide a new perspective for understanding the plasmonic coupling at metal-TMD interfaces and a reliable route toward fabricating well-defined TMDs.

Double-walled carbon nanotube film as the active electrode in an electro-optical modulator for the mid-infrared and terahertz regions

The lack of efficient optical components operating with terahertz (THz) radiation is a limiting step in the ongoing large-scale development of this technology in fields such as telecommunication and imaging. In this work, we propose the use of double-walled carbon nanotube (DWCNT) films as the active electrode in THz modulation devices. Using six bounces in an internal total reflection configuration in a silicon waveguide prism, we achieved high attenuation from a 5 nm thin film, reaching up to −ΔT/T=6% at 50 THz, albeit with a slow speed of modulation on the order of minutes. Moreover, this attenuation −ΔT/T attains a value of 20% at 30 THz using a thicker 20 nm DWCNT film. As a consequence of doping, the modulation of a phonon-related Fano resonance is also observed in the mid-infrared, which could be used as a modulable narrow-band optoelectronic filter. Our study provides a sense of the capabilities unlocked by exploiting the optical and electronic properties of carbon nanotubes in the terahertz and infrared regimes.

Seismic Interpretation and Depositional Model of Kais-Lower Klasafet Reservoirs inWalio Area of Kepala Burung PSC, Salawati Basin, West Papua, Indonesia

Kepala Burung PSC is located at onshore portion of Salawati Basin. The PSC area is divided into two area(s) namely Walio Area and Arar Area at the south and north, respectively. Numerous exploratory wells had been drilled at Walio Area which resulted several economical discoveries of oil reservoired within the reefal Kais Formation and the overlying mixed-silisiclastics carbonate of Lower Klasafet reservoirs namely U-Marker and Texturalia Intervals. The latest discoveries at this area was in 2010 by the drilling of North Walio-1 well which encountered oil reservoirs within Kais Formation. With consideration of exploration success ratio, proven petroleum system elements and thebroad distribution of Miocene Kais and Lower Klasafet; exploration in this area is still promising. Moreover, twothree-dimensional (3D) volume of seismic which acquired in 2004 and 2007 are beneficial in improving the geological understanding in this area. This study is providing seismic interpretation which weighted to seismic facies analysis within Kais-Lower Klasafet reservoirs and the depositional model of these two associated reservoirs. Seismic facies analysis within the studied reservoirs are focused to reflection characteristics such as; seismic reflection termination, continuity, amplitude, frequency and internal reflection configuration. The internal seismic reflection characteristics are compared between the successful and unsuccessful exploration drilling. Subsequently, a sketched depositional model at the times of Kais and Lower Klasafet deposition is constructed. Three seismic reservoir facies are recognised in this area; pinnacle reef-patch reef which associated to narrow topography high(s), reefal carbonate bank which associated to broad or extensive topography highs, and drowning package of carbonate-mixed-silisiclastics at the top of Kais reef(s). These types of carbonates are interpreted to be deposited within five stages of major sea level rise. The antecedent topography of the reefs is mapped to be used as reef fairways in Salawati Basin, which means will be tied to neighbouring northern Arar Area and the other adjacent areas.

Optical sizing of nanoparticles in thin films of nonabsorbing nanocolloids.

We study an optical method to infer the size of nanoparticles in a thin film of a dilute nonabsorbing nanocolloid. It is based on determining the contribution of the nanoparticles to the complex effective refractive index of a suspension from reflectivity versus the angle of incidence curves in an internal reflection configuration. The method requires knowing only approximately the particles' refractive index and volume fraction. The error margin in the refractive index used to illustrate this technique was 2%. The method is applicable to sizing nanoparticles from a few tens of nanometers to about 200nm in radius and requires a small volume of the sample, in the range of a few microliters. The method could be used to sense nanoparticle aggregation and is suitable to be integrated into microfluidic devices.

Sequence architecture and depositional evolution of Eocene to Oligocene, synrift to early postrift strata in the Baiyun Sag, South China Sea

The Pearl River Mouth Basin (PRMB), located on the northern continental margin of the South China Sea, underwent a complex evolution during the Paleogene. We have focused on the Baiyun Sag in the PRMB with the goal of constructing the architecture and depositional evolution of the Eocene–Early Oligocene synrift stage to the Late Oligocene early postrift stage of basin evolution. Based on analysis of 3D seismic data complemented by well logs and cores, the Paleogene basin fills can be classified into three composite sequences bounded by regional unconformities and 14 sequences bounded by local unconformities. We identify seismic facies on the basis of different internal reflection configurations, external shapes, and contact relationships. The distribution of seismic facies and lithologies interpreted from gamma-ray curves reveal that the synrift basin fill consists mainly of fan delta deposits adjacent to the southern fault scarp, braid delta deposits on the adjacent hanging-wall blocks, and lacustrine mudstones and sublacustrine fan deposits in the center of the basin. The overlying early postrift stage is dominated by shelf and shelf-slope environments, with widespread developed southward-prograding deltas and submarine fans. Tectonics is the principal controlling factor on the development and distribution of depositional systems during the synrift stage. In contrast, sea-level changes superimposed on long-term subsidence related to thermal cooling determined the stacking patterns of sequences during the postrift stage. The results provide new insights on synrift and early postrift tectonics and sedimentation patterns along an evolving passive margin.

Multipole Radiations from Large Gold Nanospheres Excited by Evanescent Wave

We proposed the use of the evanescent wave generated in a total internal reflection configuration to excite large gold nanospheres and investigated the radiations of the high-order plasmon modes supported in gold nanospheres. It was revealed that the evanescent wave excitation is equivalent to the excitation by using both the incident and reflected light, offering us the opportunity to control the orientation of the electric field used to excite nanoparticles. In addition, it was found that the scattering light intensity is greatly enhanced and the background noise is considerably suppressed, making it possible to detect the radiations from high-order plasmon modes. Moreover, the influence of the mirror images on the scattering induced by a metal substrate is eliminated as compared with the surface plasmon polariton excitation. By exciting a gold nanosphere with s-polarized light and detecting the scattering light with a p-polarized analyzer, we were able to reveal the radiation from the electric quadrupole mode of the gold nanosphere in both the spatial and the frequency domains. Our findings are important for characterizing the radiations from the high-order modes of large nanoparticles and useful for designing nanoscale photonic devices.

Polarization control of colors in resonant evanescent field scattering by silicon nanodisks [Invited

Using the multipole decomposition method, we study resonant evanescent field scattering by cylindrical silicon nanoparticles illuminated in the total internal reflection configuration. Scattering cross sections of nanodisks in the visible spectral range are considered, and the corresponding color representations of scattered radiation under white light illumination are simulated. It is demonstrated that the scattered light color can efficiently be controlled and tuned by the incident light polarization, with the relative contributions of nanodisk multipole moments playing a crucial role in the color formation. The polarization color control in resonant scattering by silicon nanodisks with different aspect ratios is studied in detail. The results obtained suggest new avenues for and exciting prospects in the development of color printing and multicolor displays operating on the basis of all-dielectric nanostructures.

Optical Coherent Reflection from a Confined Colloidal Film: Modeling and Experiment.

We study the optical reflectivity of confined colloidal films as a function of the angle of incidence in an internal reflection configuration. Two effective medium models and an extended coherent-scattering model for thin colloidal films are compared against experimental measurements with gold, latex, and titanium dioxide colloids. A derivation of the coherent scattering model for confined colloidal films used in this work is presented in a comprehensive way. The model lies within the framework of the multiple-scattering theory and is valid for any angle of incidence and for colloids of small or large particles compared to the wavelength of light, however, only for small and moderately small particles' volume fraction. Reflectivity versus angle of incidence curves for an opaque colloidal film in an internal reflection configuration show the effects of two critical angles. Within the two critical angles, there is a high sensitivity to the presence of colloidal particles, while the volume of colloidal samples needed is in the microliter range. Upon comparing theory with experiment, no model fitting was done in any case. The experimental setup and its calibration procedure are discussed. The results provide physical insight into applications involving optical properties of colloidal systems.

Grafting of Oligo(ethylene glycol)-Functionalized Calix[4]arene-Tetradiazonium Salts for Antifouling Germanium and Gold Surfaces.

Biosensors that can determine protein concentration and structure are highly desired for biomedical applications. For the development of such biosensors, the use of Fourier transform infrared (FTIR) spectroscopy with the attenuated internal total reflection (ATR) configuration is particularly attractive, but it requires appropriate surface functionalization of the ATR optical element. Indeed, the surface has to specifically interact with a target protein in close contact with the optical element and must display antifouling properties to prevent nonspecific adsorption of other proteins. Here, we report robust monolayers of calix[4]arenes bearing oligo(ethylene glycol) (oEG) chains, which were grafted on germanium and gold surfaces via their tetradiazonium salts. The formation of monolayers of oEGylated calix[4]arenes was confirmed by AFM, IR, and contact angle measurements. The antifouling properties of these modified surfaces were studied by ATR-FTIR spectroscopy and fluorescence microscopy, and the nonspecific absorption of bovine serum albumin was found to be reduced by 85% compared to that of unmodified germanium. In other words, the organic coating by oEGylated calix[4]arenes provides remarkable antifouling properties, opening the way for the design of germanium- or gold-based biosensors.

Bloch Surface Waves Using Graphene Layers: An Approach toward In-Plane Photodetectors

A dielectric multilayer platform was investigated as a foundation for two-dimensional optics. In this paper, we present, to the best of our knowledge, the first experimental demonstration of absorption of Bloch surface waves in the presence of graphene layers. Graphene is initially grown on a Cu foil via Chemical Vapor Deposition and transferred layer by layer by a wet-transfer method using poly(methyl methacrylate), (PMMA). We exploit total internal reflection configuration and multi-heterodyne scanning near-field optical microscopy as a far-field coupling method and near-field characterization tool, respectively. The absorption is quantified in terms of propagation lengths of Bloch surface waves. A significant drop in the propagation length of the BSWs is observed in the presence of graphene layers. The propagation length of BSWs in bare multilayer is reduced to 17 times shorter in presence of graphene monolayer, and 23 times shorter for graphene bilayer.

Towards the application of Al2O3/ZnO nanolaminates in immunosensors: total internal reflection spectroscopic ellipsometry based evaluation of BSA immobilization

Signal enhancement due to multiple reflections in a total internal reflection configuration.

The formation of giant clastic extrusions at the end of the Messinian Salinity Crisis

This paper documents the discovery of five multi-km scale lensoid bodies that directly overlie the upper surface of the thick (>1 km) Messinian Evaporite sequence. They were identified through the analysis of 3D seismic data from the western Nile Cone. The convergence of the upper and lower bounding reflections of these lensoid bodies, their external and internal reflection configuration, the positive ‘depositional’ relief at their upper surface, and the stratal relationship with underlying and overlying deposits supports the interpretation that these are giant clastic extrusions. The interpretations combined with the stratal position of these clastic extrusions demonstrate a prior unsuspected link between periods of major environment change and basin hydrodynamics on a plate scale.All five lensoid bodies were extruded onto a single, seismically resolvable marker horizon correlatable with the end of the Messinian Salinity Crisis (Horizon M). It is argued that the source of these clastic extrusions is pre-Messinian in origin, which implies massive sediment remobilisation at depth in the pre-evaporitic succession and intrusion through the thick evaporite layer. We propose that the scale and timing of this dramatic event was primed and triggered by near-lithostatic overpressure in the pre-evaporitic sediments generated through (1) their rapid burial and loading during the Messinian Salinity Crisis and (2) catastrophic re-flooding during its immediate aftermath.The largest of these clastic extrusions has a volume of over c. 116 km3, making it amongst the largest extruded sedimentary bodies described on Earth. The findings extend the understanding of the upper scale of other analogous clastic extrusions such as mud volcanoes and sediment-hosted hydrothermal systems. Following the 2006 eruption of the Lusi sediment-hosted hydrothermal system in Indonesia, an understanding of the upper scale limit of clastic extrusions has even greater societal relevance, in order to increase awareness of the risk posed by the potential size and longevity of future giant clastic extrusions.