Cloaked Facebook pages: Exploring fake Islamist propaganda in social media

This research analyses cloaked Facebook pages that are created to spread political propaganda by cloaking a user profile and imitating the identity of a political opponent in order to spark hateful and aggressive reactions. This inquiry is pursued through a multi-sited online ethnographic case study of Danish Facebook pages disguised as radical Islamist pages, which provoked racist and anti-Muslim reactions as well as negative sentiments towards refugees and immigrants in Denmark in general. Drawing on Jessie Daniels’ critical insights into cloaked websites, this research furthermore analyses the epistemological, methodological and conceptual challenges of online propaganda. It enhances our understanding of disinformation and propaganda in an increasingly interactive social media environment and contributes to a critical inquiry into social media and subversive politics

Plasmonic enhanced Schottky detectors based on internal photoemission in nano pyramids for near IR regime

We demonstrate the detection of sub-bandgap light in silicon nano pyramid using the process of internal photoemission in Schottky diode. The quantum efficiency is enhanced by using metal coated silicon nano pyramids

Silicon pyramids for plasmonic enhanced schottky photodetectors

We demonstrate the design, fabrication and characterization of plasmonic enhanced free space Schottky detector for telecom wavelength. Unique fabrication technique, simulation and measurement results will be presented and discussed. © OSA 2013

Plasmonic enhanced silicon pyramids for internal photoemission Schottky detectors in the near-infrared regime

We demonstrate a nanoscale broadband silicon plasmonic Schottky detector with high responsivity and improved signal to noise ratio operating in the sub-bandgap regime. Responsivity is enhanced by the use of pyramidally shaped plasmonic concentrators. Owing to the large cross-section of the pyramid, light is collected from a large area which corresponds to its base, concentrated toward the nano apex of the pyramid, absorbed in the metal, and generates hot electrons. Using the internal photoemission process, these electrons cross over the Schottky barrier and are collected as a photocurrent. The combination of using silicon technology together with the high collection efficiency and nanoscale confinement makes the silicon pyramids ideal for playing a central role in the construction of improved photodetectors. Furthermore, owing to the small active area, the dark current is significantly reduced as compared with flat detectors, and thus an improved signal to noise ratio is obtained. Our measurements show high responsivities over a broad spectral regime, with a record high of about 30 mA/W at the wavelength of 1064 nm, while keeping the dark current as low as ∼100 nA. Finally, such detectors can also be constructed in the form of a pixel array, and thus can be used as focal plane detector arrays

Direct observation of optical near field in nanophotonics devices at the nanoscale using Scanning Thermal Microscopy

In recent years, following the miniaturization and integration of passive and active nanophotonic devices, thermal characterization of such devices at the nanoscale is becoming a task of crucial importance. The Scanning Thermal Microscopy (SThM) is a natural candidate for performing this task. However, it turns out that the SThM capability to precisely map the temperature of a photonic sample in the presence of light interacting with the sample is limited. This is because of the significant absorption of light by the SThM probe. As a result, the temperature of the SThM probe increases and a significant electrical signal which is directly proportional to the light intensity is obtained. As such, instead of measuring the temperature of the sample, one may directly measure the light intensity profile. While this is certainly a limitation in the context of thermal characterization of nanophotonic devices, this very property provides a new opportunity for optical near field characterization. In this paper we demonstrate numerically and experimentally the optical near field measurements of nanophotonic devices using a SThM probe. The system is characterized using several sets of samples with different properties and various wavelengths of operation. Our measurements indicate that the light absorption by the probe can be even larger than the light induced heat generation in the sample. The frequency response of the SThM system is characterized and the 3 dB frequency response was found to be ∼1.5 kHz. The simplicity of the SThM system which eliminates the need for complex optical measurement setups together with its broadband wavelength of operation makes this approach an attractive alternative to the more conventional aperture and apertureless NSOM approaches. Finally, referring to its original role in characterizing thermal effects at the nanoscale, we propose an approach for characterizing the temperature profile of nanophotonic devices which are heated by light absorption within the device. This is achieved by spatially separating between the optical near field distribution and the SThM probe, taking advantage of the broader temperature profile as compared to the more localized light profile

Plasmonic enhanced near IR schottky detectors based on internal photoemission in nano pyramids

We demonstrate the detection of subbandgap light in silicon nano pyramid using the process of internal photoemission in Schottky diode. The quantum efficiency is enhanced by using metal coated silicon nano pyramids

Optically readable resistive random access memory in silicon plasmonics platform

We experimentally demonstrate resistive random access memory device integrated with a silicon plasmonic waveguide, and relying on the formation of nanoscale metallic needles. The measured electrical and optical response show distinct bistability with well-defined hysteresis

Nanoscale plasmonic memristor with optical readout functionality

We experimentally demonstrate for the first time a nanoscale resistive random access memory (RRAM) electronic device integrated with a plasmonic waveguide providing the functionality of optical readout. The device fabrication is based on silicon on insulator CMOS compatible approach of local oxidation of silicon, which enables the realization of RRAM and low optical loss channel photonic waveguide at the same fabrication step. This plasmonic device operates at telecom wavelength of 1.55 μm and can be used to optically read the logic state of a memory by measuring two distinct levels of optical transmission. The experimental characterization of the device shows optical bistable behavior between these levels of transmission in addition to well-defined hysteresis. We attribute the changes in the optical transmission to the creation of a nanoscale absorbing and scattering metallic filament in the amorphous silicon layer, where the plasmonic mode resides. © 2013 American Chemical Society