Nanophotonics Research Papers - Academia.edu (original) (raw)

The first sub-100nm technology that allows the monolithic integration of optical modulators and germanium photodetectors as features into a current 90nm base highperformance logic technology node is demonstrated. The resulting 90nm CMOS-integrated Nano-Photonics technology node is optimized for analog functionality to yield powerefficient single-die multichannel wavelength-mulitplexed 25Gbps transceivers.

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- Nanophotonics, Photodetectors, Wavelength Division Multiplexing, Electron Devices

Two twelve-channel arrays based on surface-etched slot gratings, one with nonuniformly spaced slots and another with uniformly spaced slots are presented for laser operation in the O-band. A wavelength tuning range greater than 40 nm, with a side-mode suppression ratio (SMSR) > 40 dB over much of this range and output power greater than 20 mW, was obtained for the array with non-uniform slots over a temperature range of 15°C-60°C. The introduction of multiple slot periods, chosen such that there is minimal overlap among the side reflection peaks, is employed to suppress modes lasing one free spectral range (FSR) from the intended wavelength. The tuning range of the array with uniformly spaced slots, on the other hand, was found to be discontinuous due to mode-hopping to modes one FSR away from the intended lasing mode which are not adequately suppressed. Spectral linewidth was found to vary across devices with the lowest measured linewidths in the range of 2 MHz to 4 MHz.

- by Nicolás Abadía and +1
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- Electrical Engineering, Physics, Optics, Optical Fiber Communications

Techniques for active modulation and control of plasmonic signals in future highly-integrated nanophotonic devices have advanced rapidly in recent years, with recent innovations extending performance into the terahertz frequency and femtojoule-per-bit switching energy domains. As thoughts turn towards the development of practical device structures, key technologies are compared in this review and prospects are assessed for the future development of the field. Artist's impression of a hybrid opto-/electro-plasmonic chip combining microelectronic and photonic functionalities.

- by Nikolay Zheludev
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- Quantum Physics, Microelectronics, Nonlinear Optics, Nanophotonics

Limitations of current sensors include large dimensions, sometimes limited sensitivity and inherent single-parameter measurement capability. Surface-enhanced Raman spectroscopy can be utilized for environment and pharmaceutical applications with the intensity of the Raman scattering enhanced by a factor of 10 6 . By fabricating and characterizing an integrated optical waveguide beneath a nanostructured precious metal coated surface a new surface-enhanced Raman spectroscopy sensing arrangement can be achieved. Nanostructured sensors can provide both multiparameter and high-resolution sensing. Using the slab waveguide core to interrogate the nanostructures at the base allows for the emission to reach discrete sensing areas effectively and should provide ideal parameters for maximum Raman interactions. Thin slab waveguide films of silicon oxynitride were etched and gold coated to create localized nanostructured sensing areas of various pitch, diameter, and shape. These were interrogated using a Ti:Sapphire laser tuned to 785-nm end coupled into the slab waveguide. The nanostructured sensors vertically projected a Raman signal, which was used to actively detect a thin layer of benzyl mercaptan attached to the sensors.

- by Stuart Pearce
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- Nanophotonics

In this paper the optical parameters at infrared frequencies of metallic thin films were obtained experimentally using a variable angle spectroscopic ellipsometer and used to simulate numerically the frequency response of antennas and antenna-coupled detectors at infrared frequencies (5-15 lm). The simulation results agree with previously published data and practical guidelines are presented for the design and fabrication of dipole and bowtie antennas at infrared frequencies.

- by Jorge Simon and +1
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- Antennas, Nanophotonics, Far Infrared Physics, Radiation Detectors
- by Apostolos Voutsas
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- Engineering, Nanophotonics, Applied Physics, Semiconductor Devices

Chip multiprocessor interconnects have been facing power and performances issues. While Optical Networks on Chip (ONoC) are identified as a possible solution. Recent advances in integration technologies allow stacking optical layers, which leads to the design of highly efficient optical devices avoiding waveguide crossing. The paper presents an Optical Multi-layer Network on Chip called "OMNoC", a novel circuit-switched ONoC relying on this multi-level optical layer design paradigm and based on multi-layer microresonator switches allowing efficient light coupling and low crosstalk. Comparisons with existing ONoCs indicate that OMNoC can achieve low power consumption and chip area.

- by Rabah Attia
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- Nanophotonics, Optical Waveguides, Silicon Photonics, Si

In this paper, mode generation based on an elliptical core few mode fiber (EC-FMF) is devised through an inverse function, designed using split step beam propagation method (BPM). The undesired modes from an
EC-FMF are eliminated through an appended waveguide computed from the inverse phase of undesired modes. The EC-FMF may be used as an all-optical switch.

The effect of induced transparency, which is related to photoinduced bleaching of photoabsorbers, is being intensely studied and has many applications in the field of sensing. Along with this classical effect, numerous studies on induced transparency in coupled plasmon-exciton systems, which is accompanied by the formation of hybrid states, have been recently published. The formation of a new coupled system results in various spectral modifications. For example, induced transparency manifests itself as a narrow dip in the absorption spectrum of a coupled system. This effect can be used in sensing, the feasibility of which is the main objective here, where a variety of materials and methods for obtaining the induced transparency are considered. Various morphologies and geometries of plasmonic nanoparticles are discussed as well as types of molecular absorbers to assess the most favorable combinations for the evolvement of induced transparency. The potential applications of the induced transparency effect in sensing and molecular diagnostics are summarized.

- by Yury Rakovich and +1
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- Sensors and Sensing, Nanophotonics, Plasmonics, Light-matter interaction

An overview of how viruses-retroviruses could be utilized as to instigate viral bio-weaponization and bio-warfare (much like other pathogens as bacteria, fungi, etc.), as well as a highlight of the history of how this has occurred in the past, has been presented. In particular, two issues need to be clarified here. First of all, almost all of our history of evolution prior to 5,500 years ago has been purged from the records, as well any memory of such happenings have been blank-slated from our consciousness memories. Secondly, that humanity has been lurking in the low dimensional level of consciousness, without having a clue about some of the advanced technologies with regard to the true nature of its genetics, and the possibility of its manipulation leading to genetic mutations and alien hybridization. However, as of more recently, with the advent of knowledge of radiation technological development, together with more novel approaches as nanotechnology in materials science, as well as the fact that we are beginning to better understand the nature of our bioenergetics and the role it plays in our genetics and physiognomy and holographic reality, we are beginning to get a better grasp of how a formidable nefarious alien artificial intelligence machinery can play a devastating role in our genetic modification, hybridization, as well as the using viral bio-weaponization for our demise or total annihilation. Thus, in the present paper, the author

- by Mohsen Paul Sarfarazi
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- Weapons of Mass Destruction, Nanophotonics, Nanomaterials, Nanoparticles
- by Nikolay Zheludev
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- Nanophotonics, Glass, Hybridization, Electron Optics

Research in solid-state nanophotonics and quantum optics has been recently pushing the limits in semiconductor microcavity design. High quality microcavities that confine light into small volumes are now able to drastically alter the local density of states (LDOS). Plasmonic systems can provide smaller effective confinements, however it is unclear if the benefits of confinement are good enough to balance material losses due to non-radiative
processes. This thesis presents a compendium of techniques for calculating photonic Green functions in various lossy, inhomogeneous magneto-dielectric systems. Subsequently we derive a rigorous theory of quantum light-matter interactions, valid in both weak and strong coupling limits, and show how the classical photonic Green function is developed to calculate Purcell factors, Lamb shifts, and the near and far field spectra from a single photon emitter. Using these techniques, this work investigates the classical and quantum optical properties of a variety of inhomogeneous structures, including their coupling to single photon emitters. This includes examining Purcell factors above negative index slabs and showing the convergence of many slow-light modes leads to a drastic increase in the LDOS along with large Lamb shifts. The optical trapping of metallic nanoparticles is examined
above a negative index slab and a silver half-space, showing the importance of interparticle coupling on the optical forces. Then the interaction between a quantum dot and a metallic nanoparticle is studied where far-field strong coupling effects are observed only when the metallic nanoparticle is considered beyond the dipole approximation. Finally, this work addresses the issue of the LDOS diverging in lossy materials, which necessitates a description of spontaneous emission beyond the dipole approximation; the “local field problem” in quantum optics is revisited and generalized to include local field corrections for use in any photonic medium. The strength of finite-difference time-domain techniques is demonstrated in a number of cases for the calculation of regularized Green functions in lossy inhomogeneous media. This thesis presents a comprehensive study of Green function approaches to model classical and quantum light-matter interactions in arbitrary nanophotonic structures, including quantum dots, semiconductor microcavities, negative index waveguides, metallic half-spaces and metallic nanoparticles.

- by Cole Van Vlack
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- Quantum Optics, Photonic Crystals, Nanophotonics, Electromagnetic metamaterials

An overview of what constitutes or signifies a "virus" has been presented. It is explicated that viruses are NOT solar organic living organisms, as inconsistent with what epitomizes a living organic organism, they are: (1) void of a cellular structure, (2) they do not have a digestive nor respiratory system, (3) they do not procreate but are only capable of replication, and that only occurs when they invade the cellular body of an organic living organism and manage to use the genetic material of their invaded host to replicate themselves and multiply while causing genetic mutation of their invaded host, and (4) strictly speaking, they cannot self-evolve and can only mutate with the aid of the genetic material of the cellular structure of the organic organism pf their host. There have been several different theories proposed by biologists, virologists, and generally scientists, with regard to speculations of whether viruses can be construed as living organisms, but all are problematic with regard to their arguments presented. However, one thing is quite certain, that viruses can only exist in the environments that living organism thrive. In this respect, they can best be considered as parasitic 'replicators,' not suggesting that they necessarily feed upon their hosts, but need the genetic materials of their host in order to mutate their host cells to replicate. And, although nefarious viruses can cause infection in the organic body of their host eventuated by triggering the immune response of their host body causing illness and even death of their host, not all viruses are necessarily bad. In fact, viruses may be

- by Mohsen Paul Sarfarazi
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- Bioengineering, Weapons of Mass Destruction, Nanophotonics, Bioenergy

We show explicitly how the commonly adopted prescription for calculating effective mode volumes is wrong and leads to uncontrolled errors. Instead, we introduce a generalized mode volume that can be easily evaluated based on the mode calculation methods typically applied in the literature, and which allows one to compute the Purcell effect and other interesting optical phenomena in a rigorous and unambiguous way.

- by Cole Van Vlack
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- Photonic Crystals, Nanophotonics, Green's Function

Silicon-based large-scale photonic integrated circuits are becoming important, due to the need for higher complexity and lower cost for optical transmitters, receivers and optical buffers. In this paper, passive technologies for large-scale photonic integrated circuits are described, including polarization handling, light non-reciprocity and loss reduction. The design rule for polarization beam splitters based on asymmetrical directional couplers is summarized and several novel designs for ultra-short polarization beam splitters are reviewed. A novel concept for realizing a polarization splitter-rotator is presented with a very simple fabrication process. Realization of silicon-based light non-reciprocity devices (e.g., optical isolator), which is very important for transmitters to avoid sensitivity to reflections, is also demonstrated with the help of magneto-optical material by the bonding technology. Low-loss waveguides are another important technology for large-scale photonic integrated circuits. Ultra-low loss optical waveguides are achieved by designing a Si 3 N 4 core with a very high aspect ratio. The loss is reduced further to ,0.1 dB m 21 with an improved fabrication process incorporating a high-quality thermal oxide upper cladding by means of wafer bonding. With the developed ultra-low loss Si 3 N 4 optical waveguides, some devices are also demonstrated, including ultra-high-Q ring resonators, low-loss arrayed-waveguide grating (de)multiplexers, and high-extinction-ratio polarizers.

- by John Bowers
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- Quantum Optics, Nonlinear Optics, Nanophotonics, Spectroscopy

Colloidal nanocrystals of semiconductor quantum dots (QDs) are gaining prominence among the optoelectronic materials in the photonics industry. Among their many applications, their use in artificial lighting and displays has attracted special attention thanks to their high efficiency and narrow emission band, enabling spectral purity and fine tunability. By employing QDs in color-conversion LEDs, it is possible to simultaneously accomplish successful color rendition of the illuminated objects together with a good spectral overlap between the emission spectrum of the device and the sensitivity of the human eye, in addition to a warm white color, in contrast to other conventional sources such as incandescent and fluorescent lamps, and phosphorbased LEDs, which cannot achieve all of these properties at the same time. In this review, we summarize the color science of QDs for lighting and displays, and present the recent developments in QD-integrated LEDs and display research. First, we start with a general introduction to color science, photometry, and radiometry. After presenting an overview of QDs, we continue with the spectral designs of QD-integrated white LEDs that have led to efficient lighting for indoor and outdoor applications. Subsequently, we discuss QD color-conversion LEDs and displays as proof-of-concept applications -a new paradigm in artificial lighting and displays. Finally, we conclude with a summary of research opportunities and challenges along with a future outlook.

- by Talha Erdem
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- Nanophotonics

The growing maturity of nanofabrication has ushered massive sophisticated optical structures available on a photonic chip. The integration of subwavelength-structured metasurfaces and metamaterials on the canonical building block of optical waveguides is gradually reshaping the landscape of photonic integrated circuits, giving rise to numerous metawaveguides with unprecedented strength in controlling guided electromagnetic waves. Here, we review recent advances in meta-structured waveguides that synergize various functional subwavelength photonic architectures with diverse waveguide platforms, such as dielectric or plasmonic waveguides and optical fibers. Foundational results and representative applications are comprehensively summarized. Brief physical models with explicit design tutorials, either physical intuition-based design methods or computer algorithms-based inverse designs, are cataloged as well. We highlight how meta-optics can infuse new degrees of freedom to waveguide-ba...

- by Yuan Meng
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- Artificial Intelligence, Electromagnetism, Optics, Biomedical Engineering

We study the strong coupling between photons and atoms that can be achieved in an optical nanofiber geometry when the interaction is dispersive. While the Purcell enhancement factor for spontaneous emission into the guided mode does not reach the strong-coupling regime for individual atoms, one can obtain high cooperativity for ensembles of a few thousand atoms due to the tight confinement of the guided modes and constructive interference over the entire chain of trapped atoms. We calculate the dyadic Green's function, which determines the scattering of light by atoms in the presence of the fiber, and thus the phase shift and polarization rotation induced on the guided light by the trapped atoms. The Green's function is related to a full Heisenberg-Langevin treatment of the dispersive response of the quantized field to tensor polarizable atoms. We apply our formalism to quantum nondemolition (QND) measurement of the atoms via polarimetry. We study shot-noise-limited detection of atom number for atoms in a completely mixed spin state and the squeezing of projection noise for atoms in clock states. Compared with squeezing of atomic ensembles in free space, we capitalize on unique features that arise in the nanofiber geometry including anisotropy of both the intensity and polarization of the guided modes. We use a first principles stochastic master equation to model the squeezing as function of time in the presence of decoherence due to optical pumping. We find a peak metrological squeezing of ∼ 5 dB is achievable with current technology for ∼ 2500 atoms trapped 180 nm from the surface of a nanofiber with radius a = 225 nm.

- by Xiaodong Qi
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- Quantum Computing, Quantum Optics, Quantum Information, Nanophotonics

Dynamic manipulation of wavefront is vital for massive free-space optical applications. Here we propose a set of largely tunable circular polarization splitters leveraging graphene nanoantennas with high efficiency reaching 83% and wide frequency tunability range of 2 to 5 THz. By synergizing the electrically tunable surface plasmons of graphene with phase gradient metasurface, we numerically demonstrate two kinds of polarization split-ters with complimentary graphene patterns to realize electrical tuning of operation frequency and efficient circular polarization demultiplexing. Using antennas of different geometric sizes, the device performances are investigated in several different terahertz bands. Our proposed structures can facilitate dynamically tunable broadband and high-speed applications such as polarization demultiplexing and optical switches in terahertz regime.

- by Yuan Meng
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- Nanophotonics, Metamaterials, Photonics, Graphene

Dielectric microspheres, with sizes on the order of several wavelengths, support high-quality whispering gallery (WG) modes and provide nonresonant focusing of light into tiny spots termed nanoscale photonic jets. In this chapter, we review properties of more complicated multiple-cavity systems that are formed by microspheres assembled in chip-scale structures. The resonant optical properties of such systems can be engineered on the basis of tight-binding WG modes in photonic atoms. In practical systems of coupled cavities, the optical transport properties are strongly influenced by disorder effects, leading to scattering, localization, and percolation of light. The desirable tight-binding properties require selecting more uniform spheres, which can be achieved by novel methods based on using sizeselective radiative pressure. Due to controllable dispersions for photons, collective emission and absorption, and enhanced light-matter coupling, such structures can be used for developing coupled arrays of microlasers, ultracompact high-resolution spectrometers, and sensors. The nonresonant properties of such systems are connected through subwavelength focusing of light in chains and arrays of microspheres that can be used in a variety of biomedical applications including ultraprecise laser tissue surgery.

- by Vasily Astratov
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- Nanophotonics, Percolation, Quality Factor, Q factor

— Realizing small-footprint and energy-efficient
optical switching fabrics is of crucial importance to solve the data
movement challenges faced by optical interconnection networks.
This letter demonstrates silicon photonic 2 × 2 full crossbar
switching functionality based on a single microring. The ultracompact
device is shown to successfully switch data channels
from two input ports simultaneously. Data channels in both the
multiple and the same wavelength switching experiments are
measured to be error-free. Simulation shows that by optimizing
some of the microring parameters crosstalk could be reduced.
This letter confirms the applicability of a single microring as
a 2 × 2 switch element for on-chip optical interconnects.

- by Dessislava Nikolova and +2
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- Nanophotonics, Optical switching, Silicon Photonics, Optical Amplifiers and Switches

This paper presents an investigation of broadband supercontinuum (SC) generation in photonic crystal fibers using cosh-Gaussian optical pulses. It is found that the SC spectra of these cosh-Gaussian pulses are composed of several internal oscillations. The number of the oscillations increases with an increase in the value of the cosh parameter Ω 0 . The internal structure of the SC spectra shows an asymmetric behavior, possessing fewer oscillations as we move from the lower to higher wavelength region. Our results indicate that the SC generation dynamics is dominated by self-phase modulation.

- by Swapan Konar
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- Nanophotonics

Plasmonic devices, made of apertures or antennas, have played significant roles in advancing the fields of optics and opto-electronics by offering subwavelength manipulation of light in the visible and near infrared frequencies. The development of heat-assisted magnetic recording (HAMR) opens up a new application of plasmonic nanostructures, where they act as near field transducers (NFTs) to locally and temporally heat a sub-diffractionlimited region in the recording medium above its Curie temperature to reduce the magnetic coercivity. This allows use of very small grain volume in the medium while still maintaining data thermal stability, and increasing storage density in the next generation hard disk drives (HDDs). In this paper, we review different plasmonic NFT designs that are promising to be applied in HAMR. We focus on the mechanisms contributing to the coupling and confinement of optical energy. We also illustrate the self-heating issue in NFT materials associated with the generation of a confined optical spot, which could result in degradation of performance and failure of components. The possibility of using alternative plasmonic materials will be discussed.

- by Aeron Tynes Hammack
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- Nanophotonics

A new way of converting infrared light into visible wavelengths could make it possible to detect and measure mid-infrared signals using cheap and efficient sensors like those found in mobile phone cameras. [32] Looking ahead, the team says it now plans to further explore multimode mixing in gasfilled fibres. "Such studies will be an exciting playground for nonlinear optical interactions that can provide us with new tools to tailor optical waveforms at the fewcycle level," Razzari tells Physics World. [31] Laser ignition (LI) is a promising electrode-less alternative to electronic spark ignition of lean fuel/air mixtures, offering high thermal efficiency with low harmful emissions. [30] Scientists have developed a new type of laser that can deliver high amounts of energy in very short bursts of time, with potential applications in eye and heart surgery or the engineering of delicate materials. [29] So far, the researchers' calculations do not extend to the behavior of a zero-charge polyacetylene soliton that carries spin, but they expect that it should be possible to manipulate this with a magnetic field gradient.

- by George Rajna
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- Nanophotonics

| In this paper, we review the present status of light emitters based on SiGe nanostructures. In order to be commercially valuable, these light emitters should be efficient, fast, operational at room temperature, and, perhaps most important, compatible with the Bmainstream[ complementary metal-oxide-semiconductor (CMOS) technology. Another important requirement is in the emission wavelength, which should match the optical waveguide low-loss spectral region, i.e., 1.3-1.6 m. Among other approaches, epitaxially grown Si/SiGe quantum wells and quantum dot/quantum well complexes produce efficient photoluminescence and electroluminescence in the required spectral range. Until recently, the major roadblocks for practical applications of these devices were strong thermal quenching of the luminescence quantum efficiency and a long carrier radiative lifetime. The latest progress in the understanding of physics of carrier recombination in Si/SiGe nanostructures is reviewed, and a new route toward CMOS compatible light emitters for on-chip optical interconnects is proposed.

- by David Lockwood
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- Biomedical Engineering, Nanophotonics, Epitaxial Growth, Photoluminescence

Focusing and guiding light into semiconductor nano-structures can deliver revolutionary concepts for photonic devices, which offer a practical pathway towards next-generation power-efficient optical networks. In this review, we consider the prospects for photonic switches using semiconductor quantum dots (QDs) and photonic cavities which possess unique properties based on their low dimensionality. The optical nonlinearity of such photonic switches is theoretically analysed by introducing the concept of a field enhancement factor. This approach reveals a drastic improvement in both power-density and speed, which is able to overcome the limitations that have beset conventional photonic switches for decades. In addition, the overall power consumption is reduced due to the atom-like nature of QDs, as well as the nano-scale footprint of photonic cavities. Based on this theoretical perspective, the current state-of-the-art QD/cavity switches are reviewed in terms of various optical nonlinearity phenomena that have been utilized to demonstrate photonic switching. Emerging techniques, enabled by cavity nonlinear effects such as wavelength tuning, Purcell-factor tuning and plasmonic effects, are also discussed.

- by Chao-Yuan Jin
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- Nanophotonics, Plasmonics, Optical switching, Quantum Dots

Nanophotonics promise a dramatic scale reduction compared to contemporary photonic components. This allows the integration of many functions onto a chip. Silicon-on-insulator (SOI) is an ideal material for nanophotonics. It consists of a thin layer of silicon on top of an oxide buffer. In combination with high-resolution lithography, one can define a high refractive index contrast both in horizontally and vertically, resulting in a tight confinement of light. Moreover, SOI can be processed with industrial tools now used for silicon microelectronics. There are two candidates for nanophotonic waveguides. Photonic wires are basically conventional waveguides with reduced dimensions and a high refractive index contrast. These waveguides with submicron dimensions can have bend radii of only a few micrometers. The alternative is to use photonic crystals, which confine light by the photonic band gap effect. Introducing defects in a photonic crystal creates waveguides and other functional components. To make nanophotonics commercially viably, mass-manufacturing technology is needed. While e-beam lithography delivers the required accuracy for nanophotonic structures, it is too slow. We have used deep-UV lithography, used for advanced CMOS fabrication, to make nanophotonic waveguides. The fabrication quality is very good, which translates to low propagation losses. E.g. a 500nm (single-mode) photonic wire has a propagation loss of only 0.24dB/mm. Using these low-loss waveguides, we have implemented a variety of nanophotonic components, including ring resonators and arrayed waveguide gratings.

- by S. Beckx
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- Microelectronics, Manufacturing, Photonic Crystals, Nanophotonics

A forward-projection algorithm based on Radon transform for two-dimensional surface plasmon imaging was devised to achieve nanoscale precision in determining the surface plasmon signal. A diverging laser beam at the chosen frequency was used to overcome the angular scanning in the well-known Kretschmann configuration. Multichannel sensing with improved resolution was realized. The technique was also used to find the lateral resolution of the sensor using a patterned layer of 40-nm thick SiO 2 layer on top of the metallic surface. As a surface plasmon resonance signal detector, the use of the proposed Radon transform algorithm shows nanoprecision accuracy in cases of single and multichannel sensing. The method also provides the filtered output of the signal without any extra modification and therefore, it is nonsensitive to noise. C 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).

- by Ibrahim Abdulhalim
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- Nanophotonics
- by Manuel Nieto-Vesperinas and +1
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- Optics, Nanophotonics, Electromagnetics

The in situ synthesis and patterning of CdS nanocrystals in a polymer matrix is performed via multi-photon absorption. Quantum-sized CdS nanocrystals are obtained by irradiating a cadmium thiolate precursor dispersed in a transparent polymer matrix with a focused near infrared femtosecond laser beam. High resolution transmission electron microscopy evidences the formation of nanocrystals with wurtzite crystalline phase. Fluorescent, nanocomposite patterns with sub-micron spatial resolution are fabricated by scanning the laser beam on the polymer–precursor composite. Moreover, the emission energy of the CdS nanocrystals can be tuned in the range 2.5–2.7 eV, by changing the laser fluences in the range 0.10–0.45 J cm−2. This method enables therefore the synthesis of luminescent, CdS-based composites to be used within patterned nanophotonic and light-emitting devices.

- by Andrea Camposeo and +1
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- Laser Spectroscopy, Microstructure, Electron Microscopy, Synthesis of nanoparticles

Processing of materials by ultrashort laser pulses has evolved significantly over the last
decade and is starting to reveal its scientific, technological, and industrial potential. In
ultrafast laser manufacturing, optical energy of tightly focused femtosecond or
picosecond laser pulses can be delivered to precisely defined positions in the bulk of
materials via two-/multi-photon excitation on a timescale much faster than thermal
energy exchange between photoexcited electrons and lattice ions. Control of photoionization
and thermal processes with the highest precision, inducing local
photomodification in sub- 100-nm sized regions has been achieved.
State-of-the-art ultrashort laser processing techniques exploit high 0.1–1 μm spatial
resolution and almost unrestricted three-dimensional structuring capability. Adjustable
pulse duration, spatiotemporal chirp, phase front tilt, and polarization allow control of
photomodification via uniquely wide parameter space. Mature opto-electrical/mechanical
technologies have enabled laser processing speeds approaching meters-per-second,
leading to a fast lab-to-fab transfer. The key aspects and latest achievements are reviewed
with an emphasis on the fundamental relation between spatial resolution and total
fabrication throughput. Emerging biomedical applications implementing micrometer
feature precision over centimeter-scale scaffolds and photonic wire bonding in
telecommunications are highlighted.

- by Mangirdas Malinauskas
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- Laser Physics, Nonlinear Optics, Photonic Crystals, Nanophotonics

Increasing the sensitivity of surface plasmon resonance (SPR) sensors is important to enable controlling small concentrations of materials in liquid solutions or for gas sensing. Upon using a 10-15 nm top layer of dielectric film with a high value of the real part ′ ε of the dielectric function, on top of an SPR sensor in the Kretschmann configuration, the sensitivity is improved by few times. The imaginary part ′′ ε of the top nano layer permittivity needs to be small enough in order to reduce the losses and get sharper dips. The stability of the sensor is also improved because the nano layer is protecting the silver from interacting with the environment. In the near infrared range, the sensitivity is enhanced contrary to the standard SPR mode without top nanolayer. The calculated evanescent field is enhanced near the top layer -analyte interface, thus the enhancement is partially due to this fact and partially due to an increase of the interaction length as a waveguiding effect.

- by Ibrahim Abdulhalim
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- Nanophotonics, Near Infrared, Sensors, Surface Plasmons

Optical filters are essential in a wide range of applications, including optical communications, electronics, lighting, optical sensors, and photography. This article presents recent work which indicates that optical filters can be created from specialized nanoparticle suspensions. Specifically, this article describes a theoretical optimization process for designing nanofluid-based filters for hybrid solar photovoltaic/thermal (PV/T) applications. This particular application is suitable because nanofluids can be utilized as both volumetric solar absorbers and as flowing heat transfer mediums. The nanofluid filters described in this work compare favorably with conventional optical filters for five PV cell alternatives: InGaP, CdTe, InGaAs, Si, and Ge. This study demonstrates that nanofluids make efficient, compact, and potentially low-cost, spectrally selective optical filters.

- by Gary Rosengarten
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- Quantum Optics, Nonlinear Optics, Nanophotonics, Spectroscopy

We present the conductometric behavior of a single atomic carbon nanostructure (graphene) that could be promising to infrared optoelectronic applications. A graphene nanomanipulation system with focused infrared laser source for optoelectronic property characterizations is implemented. The feasibility of mechanical and electrical probing manipulations on two-dimensional thin film nanostructures is studied. Using this system, we revealed the infrared optoelectronic properties of mono-and multilayer graphene. The obtained optoelectronic parameters are compared to the single-and multi-walled nanotubes. A graphene infrared sensor is prototyped by direct writing of electrodes using gold nanoink fountain-pen method and is analyzed by electrical probing. Results show that graphene could be a promising building block for thin film optoelectronic devices.

- by Sinan D Haliyo
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- Nanophotonics, Nanofabrication, Thin Film, Nanosensors

Metasurface is a recently developed nanophotonics concept to manipulate the properties of light by replacing conventional bulky optical components with ultrathin (more than 104 times thinner) flat optical components. Since the first demonstration of metasurfaces in 2011, they have attracted tremendous interest in the consumer optics and electronics industries. Recently, metasurface-empowered novel bioimaging and biosensing tools have emerged and been reported. Given the recent advances in metasurfaces in biomedical engineering, this review article covers the state of the art for this technology and provides a comprehensive interdisciplinary perspective on this field. The topics that we have covered include metasurfaces for chiral imaging, endoscopic optical coherence tomography, fluorescent imaging, super-resolution imaging, magnetic resonance imaging, quantitative phase imaging, sensing of antibodies, proteins, DNAs, cells, and cancer biomarkers. Future directions are discussed in ...

- by Malini Olivo
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- Nanophotonics

A three-dimensional extension of the recently demonstrated generalization of the laws of refraction and reflection was investigated for both flat and curved metasurfaces. We found that out-of-plane refraction occurs for a metasurface that imparts a wavevector out of the plane of incidence onto the incident light beam. Metasurfaces provide arbitrary control over the direction of refraction, and yield new critical angles for both reflection and refraction. A spherical metasurface with phase discontinuities leads to unconventional light bending compared to standard refractive lenses.

- by Ali Kabiri
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- Nanophotonics

ABSTRACT Optical properties of colloidal plasmonic titanium nitride nanoparticles are examined with an eye on their photothermal via transmission electron microscopy and optical transmittance measurements. Single crystal titanium nitride cubic nanoparticles with an average size of 50 nm exhibit plasmon resonance in the biological transparency window. With dimensions optimized for efficient cellular uptake, the nanoparticles demonstrate a high photothermal conversion efficiency. A self-passivating native oxide at the surface of the nanoparticles provides an additional degree of freedom for surface functionalization.

- by URCAN GULER
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- Nanophotonics

Scope & Topics Nanoscience and Technology: An International Journal (NTIJ) is a peer-reviewed, open access journal, addresses the impacts and challenges of Nanoscience and Technology. The journal documents practical and theoretical results which make a fundamental contribution for the development of Nanoscience and Technology. This journal aims to bring together researchers and practitioners in all Nano aspects, including (but not limited to): Topics Of Intrested: ■ Micro / Nano Fabrication and Metrology ■ Micro / Nano Heat Transfer and Energy Information Technology, ■ Micro / Nano Sensors , Actuators and Systems Nanobionics ■ Micro / Nanofluidics and Bio Chips ■

- by NTIJ JOURNAL
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- Polymer Chemistry, Nanomaterials Characterization, Nanoelectronics, Nanophotonics

The propagation characteristics of TE photonic modes in metal-insulator-metal (MIM) waveguides are investigated. These modes show better confinement and low propagation losses as compared to TM plasmonic modes at shorter wavelengths and at certain core thicknesses. The dielectric to MIM coupler and MIM directional couplers with 90 ∘ bends are considered. The coupling efficiency for dielectric to MIM waveguides was found to be ∼68% at 532 nm wavelength. MIM power splitters with different power ratios at output ports are also studied. The numerical analysis is performed using a two dimensional finite-difference-time-domain method.

- by Mohammed Zia Ullah Khan
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- Optical Engineering, Nanophotonics, Plasmonics, Solid-State Lighting

This work aims to design a CMOS compatible, low-electrical power consumption modulator assisted by plasmons. For compactness and reduction of the electrical power consumption, electro-absorption based on the Franz-Keldysh effect in Germanium was chosen for modulation. It consists in the change of the absorption coefficient of the material near the band edge under the application of a static electric field, hence producing a direct modulation of the light intensity. The use of plasmons allows enhancing the electro-optical effect due to the high field confinement. An integrated electro-optical simulation tool was developed to design and optimize the modulator. The designed plasmonic modulator has an extinction ratio of 3.3 dB with insertion losses of 13.2 dB and electrical power consumption as low as 20 fJ/bit, i.e. the lowest electrical power consumption reported for silicon photonic modulators. In- and out-coupling to a standard silicon waveguide was also engineered by the means of an optimized Si-Ge taper, reducing the coupling losses to only 1 dB per coupler. Besides, an experimental work was carried out to try to shift the Franz-Keldysh effect, which is maximum at 1650 nm, to lower wavelength close to 1.55 μm for telecommunication applications.

- by Nicolás Abadía
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- Electrical Engineering, Physics, Condensed Matter Physics, Optics

A wideband metamaterial (MTM) absorber based on a concentric ring resonator is discussed at visible frequencies. The proposed structure offers a wideband absorption response, where absorption of >70% is gained for the frequency ranging from 537.91 to 635.73 THz. The analysis is conducted on the components of the proposed structure to understand the origin of wideband absorption. Furthermore, a graphene monolayer sheet is integrated to the proposed MTM absorber to optimize its absorptivity, where the studies show enhancement of the absorptivity of the proposed structure up to 26% from its initial absorptivity. MTM absorbers of this kind have potential applications in solar cells.

- by Patrick RUFANGURA
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- Nanophotonics

Resonances of symmetric and antisymmetric polarization states in tightly coupled nanoshell particles made of either a metallic core and a dielectric shell or, vice versa, a dielectric core and a metallic shell were analyzed at optical frequencies. The investigation was performed by using the single dipole approximation (SDA) with all the dynamical retarded field terms included. Furthermore, analytic formulas for

- by Filippo Capolino
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- Nanophotonics, Infrared, Resonant Frequency
- by Mijanur Rahman
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- Quantum Information, Nanophotonics, Quantum Communications, Quantum entanglement