Identification: Tutorial CM7.1
Identification: Tutorial CM4.1
This tutorial introduces the audience to the basics, principles, and applications of two advanced TEM imaging techniques.
In contrast to the scintillator-based Charged Coupled Device (CCD) commonly used in TEM, direct electron detectors produce images directly from high energy electrons. The high sensitivity and high speed properties of these advanced detectors have provided material scientists with a tool to study dynamic processes at the milliseconds time scale while maintaining spatial resolution of sub-nanometer and better. In this, Part 1 of a two-part tutorial, Liang Jin covers the physics of image formation, different imaging modes including electron counting, and new image processing methods for in situ observations. Applications of the technique to in situ mechanical, liquid cell and environmental TEM are given.
This is Part One of a two-part tutorial. Part Two, Introduction to Advanced Imaging and Tomography Techniques for Transmission Electron Microscopy: Three-Dimensional Electron Tomographic for Hard and Soft Materials Research, is available here.
Identification: Tutorial ED10.1
The materials for nanoplasmonics include metals, in particular, alkaline, alkaline earth and transition metals (including noble metals such as silver, gold and platinum), semi-metals such as graphene, semiconductors (highly doped semiconductors used as plasmonic metals or lightly doped semiconductors used as gain media), topological insulators (whose surfaces can exhibit plasmonic properties) and dielectrics. In Part 1 of this four-part tutorial, Mark Stockman deals with fundamental properties of the materials. Among those, he concentrates on dispersion properties of the plasmonic materials defined by the fundamental principle of causality. The tutorial also compares metals with conducting semiconductors and graphene. Novel two-dimensional semiconductors such as transitional metal dichalcogenides are also discussed.
This is Part One of a four-part tutorial.
Identification: Tutorial CM7.2
Identification: Tutorial CM4.2
This tutorial introduces the audience to the basics, principles, and applications of two advanced TEM imaging techniques.
Three-dimensional (3D) structural analysis is essential to understand the relationship between the structure and function of an object. Electron tomography (ET) is a technique that retrieves 3D structural information from a tilt series of 2D projections, and is becoming a mature technology with sub-nanometer resolution. In Part 2 (of two) of this tutorial, Gang Ren discusses the common basis for 3D characterization, and specifies difficulties and solutions regarding both hard and soft materials research. Additionally, this part covers an overview of different experimental and computational techniques used in ET. Applications are given in 3D structural analysis of both physical-sciences research and soft materials and biomaterials research.
This is Part Two of a two-part tutorial. Part One, Introduction to Advanced Imaging and Tomography Techniques for Transmission Electron Microscopy: High-Speed Direct Electron Detectors for In Situ TEM, is available here.
Identification: Tutorial ED10.2
In Pat 2 of this four-part tutorial, Mark Stockman concentrates on spasers and spaser-based lasers. A spaser is a plasmonic nanosystem containing a metal nanoparticle, which plays a role of the plasmonic resonator, and semiconductor gain shell. The tutorial considers fundamental theory of the spaser, including both stationary (CW) operation and its ultrafast kinetics. The tutorial then reviews an extensive literature on various spasers demonstrated experimentally, and outlines fundamentals of applications of both nanospasers and lasing spasers.
This is Part Two of a four-part tutorial.
Identification: Tutorial ED10.3
In Part 3 of this four-part tutorial, Nicholas A. Kotov describes the (1) fundamental requirements, (2) practical rationale and (3) methods of manufacturing of chiroplasmonic and chiroexcitonic nanostructures. Special attention is given to mapping the future direction of translation of structural and optical properties of inorganic nanoscale structures to applications. They are exemplified by polarization optics for telecommunication, bioanalytical applications, holographic imaging and anti-counterfeit technologies.
This is Part Three of a four-part tutorial.
Identification: Tutorial CM7.3
Identification: Tutorial ED10.4
In Part 4 of this four-part tutorial, Mark Brongersma starts with an intuitive introduction to the optical properties of metamaterials. He then discusses the possibility of creating two-dimensional (2D) metamaterials from optically resonant nanoscale semiconductor and metallic building blocks. The resulting metafilms and metasurfaces are ideal building blocks for optoelectronic devices that are commonly constructed from layered metal and semiconductor films.
This is Part Four of a four-part tutorial.
Identification: V01
Research in designing and utilizing nontrivial effective refractive index values of synthetic materials has opened up exciting opportunities in optics. For example, recently, materials and metamaterials with near-zero refractive index values (i.e. “epsilon-near-zero” or “mu-near-zero”) have attracted attention due to a variety of predicted properties including the decoupling of wavelength and frequency, a divergence of the density of states, and other remarkable effects. However, material systems with refractive indices near zero are often rather lossy, limiting their utility. In this work, we explored new optical phenomena enabled by refractive indices slightly below unity, rather than very close to zero. We found that in certain polar materials close to their intrinsic phonon resonances, refractive indices less than one can be achieved with relatively low losses. These materials include silicon dioxide (SiO2), aluminum oxide, aluminum nitride, and many others. For example, in SiO2, the real part of refractive index (n) is below one in the wavelength range of 7.37 micron to 7.67 micron, where the extinction coefficient (k) remains below 0.03. Here, we present experimental demonstrations of two new optical phenomena using SiO2 in this wavelength region: frustration of external reflection, and direct coupling to surface plasmon polaritons (SPPs) from free space. When light is incident on a low-loss medium with a refractive index less than one beyond a critical angle, it is reflected with high efficiency, similar to the case of total internal reflection. While this phenomenon of external reflection (ER) is widely used in x-ray optics, it is rarely observed at optical frequencies. We demonstrate that, using SiO2 at infrared frequencies, we can observe both ER and the related phenomenon of frustrated external reflection (FER). We utilized SiO2 films with thicknesses in the range of a few micron, on the order of the evanescent decay length in the SiO2 when light is incident on the film at an oblique angle of incidence beyond the critical angle. Decreasing the film thickness is shown to increase the amount of light transmitted through the film, providing evidence of the frustration mechanism. In parallel, we demonstrated direct excitation of SPPs from free space without the need of typical momentum matching structures such as prisms and gratings. Conventionally, direct coupling of free space light to SPPs is impossible because the wave vector of the SPP is always greater than the free-space wave vector. We showed that SPPs can be excited from free space at the interface between a metal and SiO2, enabled by a reduction of the SPP wave vector in the region where the refractive index of the SiO2 is less than one and the losses are not too large.