Recent progress in the development of optical metamaterials allows unprecedented control over the flow of light at both the nano- and macroscopic scales. Metamaterials (MMs) are rationally designed artificial materials with versatile properties that can be tailored to fit almost any practical need and thus go well beyond what can be obtained with "natural" materials. We review the exciting field of optical metamaterials and discuss the recent progress in developing tunable and active MMs, nanolasers, artificial optical magnetism, semiconductor-based and loss-free negative-index MMs, and a new means for engineering the photonic density of states with MMs. A powerful paradigm of shaping space for light with transformation optics, which can enable a family of new applications ranging from a flat magnifying hyperlens to an invisibility cloak, will be also discussed. Finally, we review a new approach for broadband light bending by using meta-interfaces with plasmonic nanoantennas. The challenges and future directions for the field will be outlined.

More than 50 years after the first operation of the laser, photonics has become a mature field. It would be foolhardy to try to predict the disruptive discoveries and inventions that will no doubt create new future directions, but it is surely safe to predict steady progress along established R&D directions. Advances in the underlying fundamental sciences along with improvements in technology will enable increasing numbers of applications in the use of light as a carrier of information and energy. The transmission of information is limited by the resolution and precision with which light can be shaped or confined in time, space, and wavelength. Future advances will no doubt include finer spatial and temporal resolution and greater precision, which will enable better 3D, 4D, or 5D reading, writing, and communicating with light through "thicker" media. It will also enable sources with greater power and more efficient conversion into (or from) other forms of energy. The upcoming decades will surely see the development of new synthetic micro- and nano-structured materials with unheard of optical properties and this will lead to new optics and new applications.

In the last several years, rapid advances have been made in the field of cavity optomechanics, in which the usually feeble radiation pressure force of light is used to manipulate (and precisely monitor) mechanical motion. These advances have moved the field from the multi-km interferometer of a gravitational wave observatory, to the optical table top, and now all the way down to a silicon microchip. In this talk I will describe these advances, and discuss our own work to realize radiation pressure within nanoscale structures in the form of coupled photonic and phononic crystals (dubbed optomechanical crystals).

Organic and nanostructures are employed in various nonlinear optical applications including novel IR mode-locked fiber lasers, all-optical switching, and 3D updateable display technology. This presentation will focus on our advances in this area including: Sources: Using fiber taper based carbon nanotube saturable absorber, we have demonstrated an all-fiber thulium-doped wavelength mode-locked laser operating near 2 µm with over 50nm tuning range. All-optical switching: Liquids such as CCl4, CS2, and organic solutions in liquid core optical fiber (LCOF) offer an effective platform to study nonlinear optical phenomena, e.g. Raman scattering, four-wave mixing and supercontinuum generation. In these devices the long interaction length is combined with a strong field confinement to enable extremely low power operation. Our observation of all-optical switching using inverse Raman scattering in LCOF with > 20dB contrast at a time scale < 5ps will be described. 3D holographic display: The use of organics and nanostructures in holographic updateable 3D display will be summarized (1-2). We acknowledge support from US AFOSR, DARPA and NSF Engineering Research Center, CIAN. References 1. P. Blanche et al, Nature, Nov 4, 2010. 2. N. Peyghambarian et al, Optics and Photonics News, Dec. 2011

An important dimension of Nanophotonics, which deals with interaction between light and matter at the nanoscale, is control of excitation dynamics by manipulating local relaxation and energy transfer to judiciously utilize the excitation energy in a specific, desirable way. Metaphotonics is a rapidly emerging new direction for Nanophotonics that deals with manipulation of electric and magnetic fields and their coupling in nanoengineered materials to control the field distribution and propagation of electromagnetic waves. Dynamic Photonics utilizes switchable/transformable materials in which electrical, optical, and magnetic fields can be used to achieve dynamic and reversible control of an optical field as well as linear and nonlinear optical functions. These emerging dimensions of photonics will be presented. Their applications, which range from photonics communications, to solar energy harvesting, to sensor technology, to biomedical technology and health care, will also be highlighted.1-3 This talk will conclude with a discussion of the vast array of new opportunities in this growing field. 1. P. N. Prasad "Nanophotonics" John Wiley & Sons, (2004). 2. P. N. Prasad "Introduction to Biophotonics" John Wiley & Sons, (2003). 3. P. N. Prasad "Introduction to Nanomedicine and Nanobioengineering" John Wiley & Sons, (2012).

Traditionally magnetic properties have been obtained by using spin electrons in ground states in bulk materials. But recent nanotechnology has developed nanostructures that allow exploring the possibility of synergistic interactions between magnetic, electronic and optic functions. This may provide new properties and potential applications for detection, sensing, and renewable energy. Recently, countries such as the US, Japan, China, France, Germany, Brazil and Korea, etc have been investing seriously in the areas of novel magnetic materials, nano-magnetic materials synthesis, molecular spin physics, and magnetic structure-property characterizations. AFOSR invests and searches for new and innovative ideas, such as novel-magnetic and multifunctional materials that can be implemented for the future Air Force as well as commercial technology advancement. To achieve such objectives AFOSR facilitates International collaboration of the US and leading international scientists in both the US and abroad. The talk addresses current status and future trend on global activities on novel nanomagnetic and multifunctional materials that are supported by AFOSR.

many of the applications in photonics/electronics are based on transient electronic excitations and require a conducting substrate. However, a close proximity between the conjugated system and a conducting substrate results in the quenching of electronic excitations. Because "there is plenty of room at the top" the controlled placement of functional moecules in the third dimension above the surface must be now envisaged and is challenging towards nanosystems.This is why developed a strategy aimed at the decoupling of conjugated molecules from the surface, by lifting active entities a few Å above the surface while maintaining the lateral organization of the array.

We have started to create a plasmonic active spectral filter based on a meta-insulator-metal (MIM) structure for a developing white LED visible-light communication. The prototypical MIM structure has been made on glass slide or prism by vacuum deposition method with resistive heating. Interface between the first thinner metal layer and bulk glass region is appropriate for excitation of surface plasmon resonance (SPR) at proper excitation conditions. And spatial extension of the SPR may causes a propagating waveguide mode in the insulator layer. The resultant MIM filter may control spectral position of narrow and deep drops on reflectance curve. The characteristic reflecting property has also been analysed by a numerical electromagnetic simulation.

We have demonstrated a LED point source from a coreshell GaAs nanowire with radial p-n junction. Emission from the GaAs nanowire source naturally couples to surface plasmon polaritons that could be guided along subwavelength nanostrips. This integrated design has both light source and waveguides with deep subwavelength dimensions, and we were able to realize truly point-to-ponit routing of light in plane even with 90-degree bending and Y-splitter. Such electrically pumped integrated light source and waveguide, which works at room temperature and power-efficient, could act as essential component of realizing on-chip nanophotonic circuit.

Localized plasmon fields induced in metal nanostructures have attracted considerable attention for efficient light-matter coupling. However, it is difficult to couple single photon into single molecule with 100% coupling efficiency because of scale mismatch among photons, nanostructures, and molecules. We have achieved the high coupling efficiency between photons and metal nanostructures using a tapered fiber coupled microsphere resonator previously. In the present work, we experimentally demonstrated second harmonic generation at an Au-coated AFM tip via a tapered fiber coupled microsphere resonator using weak CW light excitation, in order to verify the efficient light-matter interaction owing to the efficient plasmon excitation.

Water droplets were either pushed or pulled with an UV light on the surface of vertically aligned and superhydrophobic ZnO nanorods (NRs). The contact angle of the droplets reduce to a lower value due to the absorption of UV by ZnO NRs and a circulating current was observed inside the droplet. The droplets were either pushed away from or pulled toward to the center of the UV light depending on the locations of the droplets to the UV light. It is obvious that in the pushing mode, the circulating current dominate the direction of the movement of the droplets, while in the pulling mode, the contact angle change dominate the direction of the droplet movement

We present experimental results obtained from the sensing of the transmitted electromagnetic field near to the surface of a thin film of gold, deposited on a substrate of glass, and with an array of circular holes. The set up used to sense the field is a SNOM (scanning near-field optical microscope). The gold film has a thickness of 100 nm, and the array consists of circular holes having a diameter of 270 nm and disposed in a bidimensional array with a period of 700 nm. We varied the angle of incidence and two different wavelengths were used (405 nm, and 632 nm).

We introduce a technique to use conventional microscope for the detection of surface plasmon polaritons (SPP) launched by nano-slits. A finely tuned layer of polymer is placed on a sub-wavelength metal-slit structure, such that the SPP momentum matches with the momentum of incident light. It enhances SPP coupling efficiency about six times relative to that without the layer. The enhanced efficiency results bright surface plasmons visible by naked eye under an optical microscope. We demonstrate how this enhanced SPP coupling can be used for parallel measurement through a simple experiment. Demonstration of slit-launched SPP measurement using conventional and widely-available optical microscopy can make nano-plasmonic device technology highly accessible and easy-to-use.

We present a new optical section fluorescent imaging technique termed metamaterials-mediated evanescent wave (MMEW) microscopy to achieve the Z (or axial)-resolution well beyond the one (~40 nm) obtained by total internal reflection fluorescence (TIRF) microscopy. The MMEW microscopy synergized plasmonic tunability of multilayer metamaterials, miniature of light emitting diode (LED), as well as sensitivity and selectivity of fluorescent probes through near-field coupling among quantum well of LEDs, surface plasmons of metamaterials, and fluorescence. We demonstrate the unique capability of metamaterials to achieve controlled Z-resolution resolution well beyond 40 nm both theoretically and experimentally.

We present nanotechnologies that improve the conversion efficiency of solar energy into electricity, and enhance the round-trip efficiency of energy storage systems. We describe nanostructures that enhance light concentration, light trapping, photon absorption, charge generation, carrier multiplication, hot electron extraction, charge transport, and current collection in photovoltaic systems, as well as nanomaterials that enhance the efficiency of electrochemical processes, boost gravimetric and volumetric energy densities, reduce the rate of self-discharge, increase the peak power rating, and extend the cycle life of secondary batteries. We also describe nanomaterials that can be used for water filtration. Membrane processes are key components of advanced water purification and desalination technologies, and nanomaterials such as carbon nanotubes, nanoparticles, and dendrimers are contributing to the development of more efficient and cost-effective water filtration processes. Additionally, we describe nanotechnologies for water remediation, which can be grouped into thermal, physico-chemical and biological methods.

We realize a novel process in fabricating RGO-MnO2 nanocomposite electrodes of thin film supercapacitors by employing intense pulsed light irradiation. This process has advantageous points as (i) cost effective, (ii) millisecond-scaled high-speed, and (iii) room-temperature condition. The pulse irradiation successfully forms the MnO2 nanoparticles in GO-Mn precursor solution and then to anchor homogeneously onto the RGO sheets being reduced by the light simultaneously. Resultant nanostructures are extensively analyzed and examined. The conductivity of the electrode, ~500-nm-sized MnO2 formation on the RGO flakes, and most importantly the high specific capacitance of ~275 F/g at 20 mV/s are measured.

The National Energy Technology Laboratory (NETL) is developing technologies for the next generation of high-efficiency low-emissions fossil-fueled power plants including oxy-fuel combustion processes for carbon capture and sequestration, and coal gasification to produce H2-rich syngas for fuel cells or combustors. Improved sensor technologies that can operate under extreme conditions (high temperature, high pressure, corrosive gases) are needed for process monitoring and control. Herein, we utilize evanescent wave absorption sensors based on nanostructured metal-oxide cladding systems. These sensors can be relevant for high temperature, harsh environment gas sensing applications. Optical modeling is performed to characterize sensor operation after exposure to relevant gases of interest. Recommendations are made regarding the functional sensing layer and the optimization of various fiber parameters based upon modeling results.

Effects of the structural properties of ebeam-deposited erbium-based thin films on their photoluminescence characteristics are reported. Prior investigations (H. Kamineni, JAP 2012) examined the effects of post-deposition annealing on the structural and optical properties of these films. The films evolved as a function of thermal treatment from an Er-rich to an ErO-rich (700°C) to an Er2O3-rich (900°C) phase due to an increase in oxygen incorporation with higher temperatures. Out-diffusion of silicon from the substrate led to erbium silicate formation at temperatures ≥ 1000°C. This study presents photoluminescence spectra of these phases and correlates the structural properties with the luminescence characteristics.

Light-field cameras capture the intensity, wavelength, and angular information of light from a scene, enabling after-the-fact focusing and 3D rendering from a single image. We have devised several nanoscale structures, including high-transparency electrospun metal gratings, densely-packed silica microspheres, and ultra-thin semiconductor nanoshells, that could be used in high-resolution, sensitive light-field camera sensors. In this study, we discuss aspects of the fabrication and integration of these nanostructures into light-field sensors and use optical and electrical simulations and measurements to elucidate suitable device architectures.

As light propagates through a disordered material, fields in various incident free space modes are mixed by scattering to generate the transport channels, linear combinations of incident modes that pass through the system. We aim to measure and address individual transport channels in disordered structures. For this purpose, we combine wavefront shaping methods and interferometric detection. Investigating light transport at the single channel level enables in depth study of interference effects and can be used to detect absorption or localization in the system.

The paper investigates the usage of photochromic Ag/TiO2 films for creating updatable random textures. The latter result from exposures with UV speckle patterns. Under optimized exposure conditions, the textures remain stable enough for a long time and the differences between textures are sufficiently discriminative to use the texturing process for goods authentication. We demonstrate that the authentication process presents the advantage to be discriminative without requiring any accurate repositioning of the manufactured product and allows to updatable random texturing.

The multiple quantum wells (MQW) Mg1-xZnxO/ZnO (x=0.18, 0.27) with different well widths Lw have been grown on c-sapphire substrates by the pulsed laser deposition method. The X-ray diffraction method shows that the interface roughness of the quantum wells was inherited from the bottom layers and did not exceed 1 nm. Owing to high structural performance of MQW the photoluminescence intensity pumped by a continuous Nd-Cd laser, abruptly enhanced at a reduction of the well width up to 2.6 nm, reaching the value that exceeds more than 30 times that of the ZnO thin film. This phenomenon is explained by an increase of charge carrier recombination rate (or by enhancement of quantum efficiency) in MQW due to quantum confinement effect. As the result, we observed lasing in the quantum wells Mg1-xZnxO/ZnO excited by a pulsed excimer KrF laser. The excitation threshold of lasing nonmonotonously depended on well width, its minimal value (~210 kW/cm2) has been achieved at Lw = 2.6 nm.

We investigate the femtosecond pulse propagation in medium with nanorods with taking into account the dependence of TPA from ellipticity of nanorods and transformation of pulse spectrum. The relation between the bandwidth of an absorption line and bandwidth of spectum of laser pulse is considered under the laser pulse propagation. We found that under certain conditions the distortion of spectrum can be minimized by taking into account the detuning of centre of aborption line from central frequency of spectrum of laser pulse.

The 65CdO-17.5B2O3-17.5SiO2 (in mol %) film was prepared on the F-doped tin oxide coated soda-lime glass substrate using screen printing and sintering processes. The effects of heat-treatment temperature on the optical properties, the crystallization, and the microstructure of film were investigated. Photoluminescence spectra of all prepared films showed strong emission with narrow bandwidth in the visible and near infrared region. Though the extent of Stokes shift of films was independent on the heat-treatment temperature, Stokes shift increased linearly with excitation energy. Furthermore, Stokes shift showed two different slopes according to the excitation energy regions.

Temperature dependence is a key parameter in designing quantum well lasers. In this work, we calculated the effects of temperature on the energy levels and emitted wavelength for PbSe/PbSrSe Single Quantum Well Laser at four different temperatures: 77K, 150K, 200K, 250K, and 300K. This material system is currently being used in Tunable Laser Spectroscopy which plays a key role in detecting biomarker molecules in exhaled breath at wavelengths in the infrared region. We determined the system design parameters to obtain the desired emitted wavelengths associated with certain disease biomarkers as a function of temperature.

Single layers of MoS2 were recently shown to be efficient emitters of photoluminescence. Here, we present scanning Raman studies of few- and single-layer MoS2 flakes, some of which have been covered with oxide layers. Raman spectroscopy is a sensitive tool to determine the number of layers of a flake due to the frequency dependence of the characteristic Raman modes. In addition to previously reported Raman modes in MoS2, we observe an interlayer shear mode at very low frequencies, which also shifts with the number of layers. In the oxide-covered flakes, we study the influence of strain on the Raman modes.

We report experimental and theoretical studies of light coupling at junctions of crossed SnO2 nanofiber waveguides as a function of gap separations, showing measurable fluctuations in power transfers when the fibers are separated by nanometer or less. The separation change at the junction can be induced by the environment such as chemical stimulants or local mechanical forces due to the ability to create large arrays of coupled fibers, and the high displacement sensitivity of the fiber coupling geometry, this architecture could play an important role in novel force-based sensors and instrumentation or chemically-induced light modulators.

The development of oxygen sensors has positively impacted the fields of medical science, bioengineering, environmental monitoring, solar cells, industrial process control, and a number of military applications. Fluorescent quenching sensors have an inherent high sensitivity, chemical selectivity, and stability when compared to other types of sensors. While cerium oxide thin films have been used to monitor oxygen in the gas phase, the potential of cerium oxide (ceria) nanoparticles as the active material in sensor for oxygen gas has only recently been investigated. Ceria nanoparticles are one of the most unique nanomaterials that are being studied today due to the diffusion and reactivity of its oxygen vacancies, which contributes to its high oxygen storage capability. The reactivity of the oxygen vacancies, which is also related to conversion of cerium ion from the Ce+4 to Ce+3 state, affects the fluorescence properties of the ceria nanoparticles. Our research demonstrates that the ceria nanoparticles (~7 nm in diameter) have application as a fluorescence quenching sensor to measure dissolved oxygen in water. We have found a strong inverse correlation between the amplitude of the fluorescence emission (excitation = 430 nm and peak = 520 nm) and the dissolved oxygen concentration between 5 - 13 mg/L. The Stern-Volmer constant, which is an indication of the sensitivity of gas sensing is 184 M-1 for the ceria nanoparticles. The results show that ceria nanoparticles can be used in an improved, robust fluorescence sensor for dissolved oxygen in a liquid medium.

A sandwich structure including subwavelength grating and low-index thin film as a broadband polarizing mirror (BPM) is demonstrated. The BPM is studied by using the rigorous coupled-wave analysis (RCWA) numerical scheme. The results present that while the thickness (tL) of low-index thin film is larger than 0.6 micrometer, the reflectivity of TE wave is larger than 0.95 in the wavelength region [1.29 micrometer, 1.66 micrometer] under the normal incidence. Meanwhile, it is also found that while the thickness of low-index thin film is about 0.9 micrometer, the extinction ratio of TM polarization is less than 0.047 in the wavelength region [1.35 micrometer, 1.48 micrometer]. Therefore, the BPM can facilitate the use of optical components such as beam splitters, isolators, display, fiber optic, and wave plates in nanophotonic.

By using conventional CMOS process, we have manufactured thermoelectric device using 50nm width silicon nanowires. Also, silicon/silicide heterostructure is implemented using ErSi1.7 for n-leg and PtSi for p-leg. The obtained maximum Seebeck coefficient values are 122 V/K for p-leg and -94 V/K for n-leg, respectively.

In this study, we try numerical analysis of stochastic resonance(SR) in a huge quantum dot network by Monte Carlo simulation. If Coulomb Blockade(CB) is observed in the network under noisy environment, the network will become device harnessing SR. First of all, quantum dots are arrayed to create networks. Second, each dot is connected by tunneling junctions. Third, bias voltage and thermal noise are applied to the network to simulate its operation. In smaller network, we could not observe CB under thermal noise environment. However, in larger network, we observed CB. It indicates our network is expected to overcome the noise.

In recent report, we have succeeded in making architecture for a single-electron circuit, which has tolerance for thermal noise. In this study, we try to design new circuit that can overcome device errors caused by manufacturing fluctuation, i.e., we try to design device error redundant circuits, besides a thermal noise redundancy. The device error redundant architecture is expected to provide that the parameter matching in fabrication process will be omitted. We simulated and researched circuit redundancy for noise caused by device error. It indicates that the proposed circuit architecture will give the device error redundant single-electron device.

In this paper we propose a highly reproducible manufacturing method for nanostructured surfaces deposited on glass substrates, these useful for molecular detection by mean of Surface Enhanced Raman Scattering (SERS). We use Rhodamine-B molecules for the detection and check experimentally the Surface Enhanced Raman Scattering by comparing measurements on the nanostructured substrate and glass. Finally we also check the high reproducibility for obtaining the Raman signal by several measuring on substrate.

We have reported a scanning absorption nanoscopy (SAN) system combining a near-field scanning optical microscope with an absorption spectroscope using supercontinuum radiation generated by coupling a mode-locked Ti:sapphire pulse laser to a nonlinear photonic crystal fiber as a light source. For the performance test of the system, the absorption spectrum and near-field absorption image of Rhodamine 6G were observed. As the SAN system allows us to investigate the absorption properties and distribution of samples blending two or more materials through high spatial resolution, this system is expected to be effectively applied in a wide variety of research areas.

We employ a commercial laser writer (Heidelberg DWL66) and a mask aligner (SUSS MJB4) for fabrication of free-form continuous surface relief micro-optical elements. Detailed fabrication processes and application of each micro-optical element will be discussed in the presentation for 3D integral imaging and display, generation of Airy beams for depth of focus enhancement and optical manipulation and others, respectively. Furthermore, we demonstrate a new way to decrease the roughness of micro-optical elements fabricated by a commercial laser writer (Heidelberg DWL66). Finally, we discuss a method of adding a grating onto a common continuous surface relief micro-optical to eliminate the fabrication error. Experimental results validate that our methods can substantially improve quality of beams produced by the modified micro-optical elements. The proposed methods give rise to a simple, reliable and low-cost micro-optical element solution for the generation of high quality novel beams.

Layer dependent physical responses of graphene-based polymer composites to near-infrared (NIR) light are reported. Thin film polymer composites were fabricated and compared utilizing both single layer graphene and few layer graphene (~5 layers). NIR-induced axial stress and kinetics were measured and found to exhibit three distinct pre-strain dependent response states. Composite stress responses, elastic moduli, and efficiencies were observed to depend on the number of graphene layers in the two-dimensional crystal.

We fabricate and experimentally demonstrate the integrated optical temperature sensor based on whispering gallery mode (WGM) with silicon nitride (Si3N4) micro-disk resonator. Because of high refractive index and very low optical loss for visible and infrared light, Si3N4 have been widely used for integrated optical components such as waveguide and resonator. The sensing is possible due to the thermally induced refractive index change and the thermal expansion of resonator materials. We measured the transmission spectra of micro-disk resonator depending on temperature and the resonance frequency, which is sensitive to the geometry and the refractive index of resonator, was monitored to calibrate the temperature.

EUV interference lithography (EUV-IL) enables fabrication of high-resolution nanostructures over large-areas with high throughput. We show the ability of patterning versatile nanostructures with EUV-IL. Not only periodic arrays of lines and dots with tunable spacing, periodicity, and sizes down to 12 nm, but also various types of complex patterns, such as kagome and concentric rings as well as quasi-periodic (Penrose) structures, are fabricated by EUV-IL using phase-engineered multiple-beam interference. Furthermore, we present multiplexed serial writing of arbitrary patterns using Bessel beams at the EUV wavelength. These high-resolution nanostructures over large-area could find potential applications in nanophotonics.

Femtosecond laser pulses were used to drill throughout holes in the optical single and multi-mode fibers. Diameter of the drilled holes was in the range between 10 to 50 micrometers. We propose a simple and low price microfluidic channel fabrication technique. The proof-of-the-principle demonstration of fiber's integration into a microfluidic channel is presented. We show that fabricated holes in the optical fiber can be used for measurement of absorption and refractive index changes of liquid samples inside the microfluidic channel. Simple design and integration possibility of laser-fabricated fiber sensors is prospective for optofluidic applications.

This study proposed a simple method to fabricate selectively patterned periodic metal nanodots by block copolymer self-assembly and electron beam lithography. We fabricated thin films of perpendicularly oriented poly(methyl methacrylate) (PMMA) cylinders in polystyrene (PS) matrix onto a neutral substrate by PS-block-PMMA self-assembly. Nanoporous structures were obtained only in exposed areas by electron beam lithography. After evaporation of metal and ultrasonication in tetrahydrofuran, 1 µm line patterned periodic metal nanodots (diameter: 20 nm, pitch: 40 nm) were fabricated in selective areas. These selectively patterned periodic metal nanodots will be applied to photonic, plasmonic and magnetic storage devices.

Metallic materials can be permanently deformed into macro- and meso-scale structures. However, as the feature size decreases, metal forming has been proven to be increasingly difficult due to the limited formability. Here, we report a strategy to directly shape nanofeatures aluminum foils. This method is based on laser shock induced high-strain-rate forming, which leads to significantly enhanced plasticity and mechanical strength. Microstructure analysis indicates that the nanoscale ultrahigh formability is due to the formation and evolution of nanocrystals during the deformation process. This method of nanoforming opens a new way to mass production of complex nanocomponents with superior mechanical properties.

Azobenzene-based polymeric materials have the unique capability of undergoing large-scale surface mass transport, allowing one to inscribe photoinduced surface patterns on thin azo-polymer films. For instance by irradiating the sample with a sinusoidal interference pattern, the intensity/polarization distribution of the incident light field is "recorded" onto the azo-polymer film as a high-modulation-depth surface-relief grating. We demonstrate the use of azobenzene surface-relief gratings for obtaining large-area 1D and 2D silicon nanostructures with feature sizes below 100 nm. The proposed fabrication technique is simple and straightforward, providing an attractive alternative to optical interference lithography based on conventional photoresists.

Optical forces play an important role in the emerging field of nano-opto-mechanical systems. We study the optical force in a prototype of subwavelength metallic structures-the nanowire pair-where the force can be increased by resonant field enhancement. We first demonstrate that the electric and magnetic dipole resonances of the nanowire pair lead to strong repulsive and attractive forces. Subsequently, we show that the nature of the optical force is changed dramatically when the nanowire pairs get stacked in an array. All these effects can be explained in terms of the Coulomb, dipole-dipole, and Lorentz interactions between the charge distributions.

Large light-induced reversible and elastic responses of graphene nanoplatelet (GNP) polymer composites are reported. Homogeneous mixtures of GNP/polydimethylsiloxane (PDMS) composites (0.1-5 wt%) were prepared and their infrared (IR) mechanical responses studied with increasing pre-strains. The actuation responses of the graphene polymer composites depended on the applied pre-strains. At low levels of pre-strain (3-9%) the actuators showed reversible expansion while at high levels (15-40%) the actuators exhibited reversible contraction. The GNP/PDMS composites exhibited higher actuation stresses compared to other forms of nanostructured carbon/PDMS composites, including carbon nanotubes (CNTs), for the same fabrication method.

Plasmons in metal nanoparticles are capable of confining the electromagnetic energy and increasing the optical intensity under external illumination. These are the main reasons why plasmons are finding a broad range of applications, including ultrasensitive biosensing, catalysis, and nanoscale trapping. Here, we review recent advances in the application of cathodoluminescence, electron energy-loss, and optical spectroscopies to gain access into the nanoparticle response and the main characteristics of their plasmons. A critical comparison of these techniques will be presented, along with examples of recent experiments and simulations, and prospects for future developments.

Nowadays many efforts are being invested in robotics using new materials and technologies to make humanoid robots look like human beings. Bio-inspired mechanisms and systems have been developed to imitate the forms and processes existing in nature. Nematic elastomers, especially the ones based on liquid crystal elastomers (LCE) are a clear example of a material suitable for this destiny. Taking advantage of their ability to reversibly change shape under external stimuli, e.g. temperature, electric field and light, LCEs are being used for development of artificial muscles. Human eye is a very complex organ that comprises a system of muscles, commonly known as iris that contracts in response to the amount of environmental light incident on it, as well as complex physiological processes. A bio-inspired artificial iris, based on the photoactuation phenomenon of LCEs, is presented in this paper. The proposed element is an overture to future work on building an artificially made humanoid eye, which is to be designed controlled by the intensity of applied light only, similar to the human-eye pupil, without the use of circuitry or electrical contacts. In this paper, first results of dilatation and constriction movements of the artificial pupil are presented, characterized under temperature and illumination, as a function of the power applied.

Functional materials have been wisely constructed via bottom-up approaches as seen in preparation of molecular and nano patterns and complexes, organized nanostructures, and function materials. However, novel concepts to bridge nano (molecular) structures and bulk systems now becomes crucial in order to control real nano and molecular functions from our visible macroscopic worlds. Here we propose a novel methodology "hand-operating nanotechnology" where molecular orientation, organization and even functions in nanometer-scale can be operated by our macroscopic (hand) operation.

The use of optical excitation in MEMS elements triggers several mechanisms that can be properly used for enhancing its mechanical response. This is particularly interesting when MEMS components are used as the transducer element on energy harvesting applications involving opto-mechanical conversion schemes. One of the pathways is based on the thermal response of the vibrating structures. In this contribution we have analyzed how a MEMS structure consisting on a clamped-clamped beam responds mechanically to the heating of the element. This heating is produced by the currents induced on an optical nanoantenna integrated on top of the suspended beam, by the optical illuminating radiation in the IR band. The effect can be enhanced by a proper design of the nanoantenna geometry, involving resonant elements, absorbance, and the presence of optical interference located at the region of the MEMS device. Both, the optical absorbance and the energy conversion to the thermal domain of the hybrid nanoantenna-MEMS device are analyzed. Additionally, the transduction to the mechanical domain in the form of beam vibrations of the optical energy absorbed by the structure and transformed into heat is also modeled. This paper focus on the analytical model that is necessary to understand the involved physical mechanisms and the results obtained from the simulation of the devices.

The growing interest to development of artificial muscles for robotic applications drives ahead the hot topic of actuators made of soft materials. Bistable actuators have an advantage to withstand external forces without energy consumption required only for switching between the states of the actuator. In this work we demonstrate that changing the illumination dynamics we can switch between the states of a bistable actuator working on buckling effect to one position or another while illuminating the sample from just one side. The actuator is made of liquid crystal elastomer (LCE) with embedded carbon nanotubes (CNTs). LCE-CNT contracts when exposed to light. The contraction is due to LC disordering induced by heat generated by light absorbed in CNTs. The phenomenon takes place when the elastomer is heated to temperatures above the transition point. The elastomer sample exposed to light demonstrates dynamic bending due to inhomogeneous strain distribution caused by exponential heat generation across the thickness of the film. Stress distribution on the film might be controlled by the shape of light pulses inducing it. Bistable actuator built using these phenomena can be operated by a single light source if preferential buckling direction is created by designing a specific geometry of a supporting cell. When fully illuminated, the sample shrinks, and when the light is off, the sample elongates and buckles towards the preferential direction. If light is slowly dimed out then the stress gradient inside the film is created and the initial buckling forces the sample to buckle towards the other direction.

Dimensional dependence of mechanical response in carbon nanostructure composites to near-infrared (NIR) light are reported. Using polydimethylsiloxane, a common silicone elastomer, composites were fabricated with one-dimensional multi-wall carbon nanotubes (MWCNTs), two dimensional single-layer graphene, two and a half-dimensional graphene nanoplatelets, and three dimensional highly ordered pyrolytic graphite. For a given carbon concentration, both steady-state photomechanical stress response and energy conversion efficiency were found to be directly related to dimensional state of carbon nanostructure additive. Actuation and relaxation kinetic responses were found to be related not to dimensionality, but to the percolation threshold of carbon nanostructure additive in the polymer.

Photoisomerization of azobenzene upon S1 excitation is studied using high-level ab initio molecular dynamics simulations in the gas phase and in solution (QM/MM approach) employing the fewest-switches surface hopping method. The isomerization occurs purely as a rotational motion of the central CNNC moiety. Two non-equivalent rotational pathways, corresponding to clockwise or counterclockwise rotation, are available. The course of the rotational motion is strongly dependent on the initial conditions. The internal conversion occurs via a S0/S1 crossing seam located near the midpoint of both of these rotational pathways. The effect of the solvent will be also discussed.