Nanophotonics Based on Semiconductor-Photonic Crystal/Quantum Dot and Metal-/Semiconductor-Plasmonics (original) (raw)
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Fabrication of Large Scale Nanofocusing Device Based on Negative Refraction Index Photonic Crystals
inoa.it
Since Abbe formulated his wave theory for microscopic imaging, the improvement of resolution of optical microscopes has been the aim of many research efforts. In the search for the maximum resolution, emphasis has been generally placed on the use of modern microscope objectives with the highest available numerical aperture (NA). But even with the best optical elements the use of conventional optical microscopes to image three-dimensional fluorescent samples has the drawback that any image focused at certain depth in the sample contains blurred information from the rest of the sample. This fact gives rise to 3-D images with strongly deteriorated contrast. In this context, this talk will be mainly devoted to optical-sectioning fluorescence techniques. Among them we cite single-photon confocal microscopes, confocal theta microscopy, structured-illumination microscopy, or selective plane illumination microscopy. Other solution is achieved by the use of two-photon excitation scanning microscopy, like in the case of 4Pi microscopes or the stimulated emission depletion microscopy.
Plasmon-like surface states in negative refractive index photonic crystals
Effects of band non-parabolicity on cavity modes in photonic crystals J. Appl. Phys. 113, 063105 (2013) Blazed phononic crystal grating Appl. Phys. Lett. 102, 034108 Two-photon-absorption photodiodes in Si photonic-crystal slow-light waveguides Appl. Phys. Lett. 102, 031114 Accurate alignment of a photonic crystal nanocavity with an embedded quantum dot based on optical microscopic photoluminescence imaging Appl. Phys. Lett. 102, 011110 Enhancement of optical effects in zero-reflection metal slabs based on light-tunneling mechanism in metamaterials AIP Advances 2, 041412 Additional information on Appl. Phys. Lett.
Plasmon assisted photonic crystal quantum dot sensors
2007
We report Quantum Dot Infrared sensors where light coupling to the self assembled quantum dots is achieved through plasmons occurring at the Metal-Semiconductor interface. The detector structure consists of an asymmetric InAs/InGaAs/GaAs DWELL structure and a thick layer of GaAs sandwiched between two highly doped n-GaAs contact layers, grown on a semi-insulating GaAs substrate. The aperture of the detector is covered with a thin metallic layer which along with the dielectric layer confines light in the vertical direction. Sub-wavelength two-dimensional periodic patterns etched in the metallic layer covering the aperture of the detector and the active region creates a micro-cavity that concentrate light in the active region leading to intersubband transitions between states in the dot and the ones in the well. The sidewalls of the detector were also covered with metal to ensure that there is no leakage of light into the active region other than through the metal covered aperture. An enhanced spectral response when compared to the normal DWELL detector is obtained despite the absence of any aperture in the detector. The spectral response measurements show that the Long Wave InfraRed (LWIR) region is enhanced when compared to the Mid Wave InfraRed (MWIR) region. This may be due to coupling of light into the active region by plasmons that are excited at the metal-semiconductor interface .The patterned metal-dielectric layers act as an optical resonator thereby enhancing the coupling efficiency of light into the active region at the specified frequency. The concept of plasmon-assisted coupling is in principle technology agnostic and can be easily integrated into present day infrared sensors.
Opportunities and Challenges of Using Plasmonic Components in Nanophotonic Architectures
IEEE Journal on Emerging and Selected Topics in Circuits and Systems, 2012
Nanophotonic architectures have recently been proposed as a path to providing low latency, high bandwidth network-on-chips. These proposals have primarily been based on micro-ring resonator modulators which, while capable of operating at tremendous speed, are known to have both a high manufacturing induced variability and a high degree of temperature dependence. The most common solution to these two problems is to introduce small heaters to control the temperature of the ring directly, which can significantly reduce overall power efficiency. In this paper, we introduce plasmonics as a complementary technology. While plasmonic devices have several important advantages, they come with their own new set of restrictions, including propagation loss and lack of wave division multiplexing (WDM) support. To overcome these challenges we propose a new hybrid photonic/plasmonic channel that can support WDM through the use of photonic micro-ring resonators as variation tolerant passive filters. Our aim is to exploit the best of both technologies: wave-guiding of photonics, and modulating using plasmonics. This channel provides moderate bandwidth with distance independent power consumption and a higher degree of temperature and process variation tolerance. We describe the state of plasmonics research, present architecturally-useful models of many of the most important devices, explore new ways in which the limitations of the technology can most readily be minimized, and quantify the applicability of these novel hybrid schemes across a variety of interconnect strategies. Our link-level analysis shows that the hybrid channel can save from 28% to 45% of total channel energy-cost per bit depending on process variation conditions.
2003
Nanostructured materials formed by metal nanocrystals (NCs) embedded in a dielectric matrix show special optical properties in the spectral range close to the plasmon resonance wavelength. Some of the potential applications in integrated optoelectronic devices that have been suggested for these materials are related either to their linear optical properties (long-wavelength pass filters) or the non-linear optical ones (ultrafast optical switches). For these applications it is essential to control their optical spectral response in the vicinity of the surface plasmon resonance (SPR). The absorption of these materials is usually described in terms of the optical properties of both the NCs and the host material, and it also depends on the dimensions and shape of the NCs. However, the optical response in metaldielectric structures can be also controlled by producing periodic photonic structures, as it has been theoretically demonstrated for the case of metal thin layers [1,2]. Nevertheless experimental reports based on photonic structuring of NCs systems have been very limited.
Journal of Nanomedicine & Nanotechnology, 2013
TIn this paper, we report the design, the fabrication and the near field optical microscopy of Negative Index Material (NIM) and GRadient INdex (GRIN) photonic crystal based flat lenses. They were fabricated on the basis of an InPbased photonic crystal technological platform including hole and pillar networks fabrication at nanometer scale. They show the possibility of sub-wavelength focusing by all dielectric periodic or quasi-periodic crystals. Particular attention is paid to the analysis of SNOM images using three-dimensional simulations. Finally, in order to demonstrate the versatility of our approach, a two-dimensional cloaking device mixing hole and pillar arrays is evaluated to pave the way for future integrated nanophotonic devices with complex functionalities.
Colloidal Quantum Dot Integrated Light Sources for Plasmon Mediated Photonic Waveguide Excitation
ACS Photonics, 2016
We operate micron-sized CdSe/CdS core− shell quantum dot (QD) clusters deposited onto gold patches as integrated light sources for the excitation of photonic waveguides. The surface plasmon mode launched by the QD fluorescence at the top interface of the gold patches are efficiently coupled to photonic modes sustained by titanium dioxide ridge waveguides. We show that, despite a large effective index difference, the plasmonic and the photonic modes can couple with a very high efficiency provided the vertical offset between the two kinds of waveguides is carefully controlled. Based on the effective index contrast of the plasmonic and the photonic modes, we engineer in-plane integrated hybrid lenses. The hybrid lenses are obtained by shaping the contact interface between the plasmonic and the photonic waveguides. We demonstrate a 2-fold enhancement of the coupling efficiency for tapers equipped with a hybrid lens. Our results are expected to be useful for the development of low-cost, integrated light sources deployed in photonic circuits. F ully integrated photonic devices are typically comprised of passive photonic components and active elements, including sources and detectors. The integration of solid-state light sources in photonic integrated circuits is most often an expensive and technologically challenging procedure whatever the waveguiding material platform. 1 On the other hand, colloidal quantum dots (QDs) have been identified as a costeffective and efficient solution for the development of light emitting diodes. 2,3 Hence, whenever an incoherent, low bandwidth, broad spectrum light source is needed, colloidal QDs offer a strategic alternative to complex heterostructures. It was suggested recently that colloidal QDs could be operated as surface plasmon sources when arranged in a controlled way at the micron scale 4 or the nanoscale. 5 The interaction of colloidal QDs with waveguide modes is also reported in the literature, 6−8 but so far only little is done in the direction of hybrid plasmophotonic coupling configurations of colloidal integrated light sources. In this work, we investigate configurations comprised of gold thin film patches optically connected to titanium dioxide (TiO 2 ) ridge waveguides. The QD clusters are deposited onto the metal patches and the surface plasmon modes launched by the QD fluorescence are coupled to the photonic modes of the TiO 2 waveguides. The interest of an hybrid approach for the QD fluorescence excitation of the photonic waveguides is 2-fold. First, a plasmon-assisted excitation is efficient at selecting a well controlled polarization state impinging the entrance of the photonic waveguide. Second, a hybrid configuration offers the opportunity to develop in-plane integrated micro-optics for improved light injection. Indeed, by taking advantage of the high effective index contrast between the plasmonic and the photonic modes, we show that in-plane integrated optical elements such as lenses can be implemented by a careful design of the transition surface between the metal patches and the photonic waveguides. Such configurations are of practical interest down to the single-QD level for the development of plasmon assisted integrated colloidal single-photon sources. 9 Although the hybrid plasmophotonic configurations demonstrated in this work rely on TiO 2 waveguides, our approach is not restricted to visible spectral domain and may be extended to other waveguiding platform such as silicon-on-insulator and emitting materials (PbS QDs, for example).
Plasmon assisted photonic crystal quantum dot sensors
Nanophotonics and Macrophotonics for Space Environments, 2007
We report Quantum Dot Infrared Detectors (QDIP) where light coupling to the self assembled quantum dots is achieved through plasmons occurring at the metal-semiconductor interface. The detector structure consists of an asymmetric InAs/InGaAs/GaAs dots-in-a-well (DWELL) structure and a thick layer of GaAs sandwiched between two highly doped n-GaAs contact layers, grown on a semi-insulating GaAs substrate. The aperture of the
Ultrathin Nanostructured Metals for Highly Transmissive Plasmonic Subtractive Color Filters
CLEO: 2014, 2014
Plasmonic color filters employing a single optically-thick nanostructured metal layer have recently generated considerable interest as an alternative to colorant-based color filtering technologies, due to their reliability, ease of fabrication, high color tunability. However, their relatively low transmission efficiency (~30%) is an important challenge that needs to be addressed for practical applications. The present work reports, for the first time, a novel plasmonic subtractive color filtering scheme that exploits the counter-intuitive phenomenon of extraordinary low transmission (ELT) through an ultrathin nanostructured metal film. This approach relies on a fundamentally different color filtering mechanism than that of exsiting plasmonic additive color filters, and achieves unusually high transmission efficiencies of 60~70% for simple architectures. Furthermore, owing to short-range interactions of surface plasmon polaritons at ELT resonances, our design offers high spatial resolution color filtering with compact pixel size close to the optical diffraction limit (~λ/2), creating solid applications ranging from imaging sensors to color displays. Color filters are vital components for digital photography, projectors, displays, image sensors and other optical measurement instrumentation. Traditional on-chip color filters that employ organic dyes or chemical pigments are vulnerable to processing chemicals, and suffer 2 from performance degradation under long-duration ultraviolet irradiation or at high temperatures. Furthermore, highly-accurate lithographic alignment techniques are required to pattern each type of pixel over a large area, increasing fabrication difficulty and cost [1-3]. One promising approach to overcome these challenges is the use of plasmonic color filters [1-10]. For instance, a single optically-thick metal layer perforated with periodic subwavelength hole arrays can exhibit the well-known extraordinary optical transmission (EOT) phenomenon [11-13], which has been extensively studied for color filtering over the past decade. These plasmonic additive color filters (ACFs) block the whole visible spectrum except for selective transmission bands that are associated with the excitation of surface plasmon polaritons (SPPs) [1,2,5-13]. These EOT transmission bands can be spectrally tuned throughout the entire visible spectrum by simply adjusting geometric parameters, such as the periodicity, shape and size of the holes, leading to the wide color tunability. Single-layer metal nanostructures also have advantages over colorantbased materials due to their ease of fabrication and device integration, and greater reliability under high temperature, humidity and long-term radiation exposure [1,6-8]. In spite of these significant advantages, the low transmission efficiency of hole-array plasmonic ACFs (~30% at visible wavelengths) remains as a bottleneck that limits their commercial applications [7]. Recently, peak transmission efficiencies of 40~50% were achieved in the state-of-art hole-array plasmonic ACFs by matching the refractive indices of media on both sides of the metal film [1], which, however, is still far below that for commercial image sensors (~80%, FUJIFILM Electronic materials U.S.A., Inc.). Plasmonic ACFs formed by metal-insulator-metal (MIM) or metal-dielectric (MD) waveguide nanoresonators have recently achieved high transmission efficiencies of 50~80% [2,9,10]. Nevertheless, these complex multilayer designs are not suitable for cost-effective nanofabrication and device integration. In this context, it is highly desirable to