Modern nanotechnology allows one to scale down various important devices (sensors, chips, fibers, etc.) and thus opens up new horizons for their applications. The efficiency of most of them is based on fundamental physical phenomena, such as transport of wave excitations and resonances. Short propagation distances make phase-coherent processes of waves important. Often the scattering of waves involves propagation along different paths and, as a consequence, results in interference phenomena, where constructive interference corresponds to resonant enhancement and destructive interference to resonant suppression of the transmission. Recently, a variety of experimental and theoretical work has revealed such patterns in different physical settings. The purpose of this review is to relate resonant scattering to Fano resonances, known from atomic physics. One of the main features of the Fano resonance is its asymmetric line profile. The asymmetry originates from a close coexistence of resonant transmission and resonant reflection and can be reduced to the interaction of a discrete (localized) state with a continuum of propagation modes. The basic concepts of Fano resonances are introduced, their geometrical and/or dynamical origin are explained, and theoretical and experimental studies of light propagation in photonic devices, charge transport through quantum dots, plasmon scattering in Josephson-junction networks, and matter-wave scattering in ultracold atom systems, among others are reviewed.

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Fano resonances in nanoscale structures

The optical properties of the light-absorbing, carbonaceous substance often called “soot,” “black carbon,” or “carbon black" have been the subject of some debate. These properties are necessary to model how aerosols affect climate, and our review is targeted specifically for that application. We recommend the term light-absorbing carbon to avoid conflict with operationally based definitions. Absorptive properties depend on molecular form, particularly the size of sp 2-bonded clusters. Freshly-generated particles should be represented as aggregates, and their absorption is like that of particles small relative to the wavelength. Previous compendia have yielded a wide range of values for both refractive indices and absorption cross section. The absorptive properties of light-absorbing carbon are not as variable as is commonly believed. Our tabulation suggests a mass-normalized absorption cross section of 7.5 ± 1.2 m2/g at 550 nm for uncoated particles. We recommend a narrow range of refractive indices for s...

https://www.tandfonline.com/doi/pdf/10.1080/02786820500421521

Light Absorption by Carbonaceous Particles: An Investigative Review

Description of the NCAR Community Atmosphere Model (CAM 3.0)

Artificially structured metamaterials have enabled unprecedented flexibility in manipulating electromagnetic waves and producing new functionalities, including the cloak of invisibility based on coordinate transformation1,2,3. Unlike other cloaking approaches4,5,6, which are typically limited to subwavelength objects, the transformation method allows the design of cloaking devices that render a macroscopic object invisible. In addition, the design is not sensitive to the object that is being cloaked. The first experimental demonstration of such a cloak at microwave frequencies was recently reported7. We note, however, that that design7 cannot be implemented for an optical cloak, which is certainly of particular interest because optical frequencies are where the word ‘invisibility’ is conventionally defined. Here we present the design of a non-magnetic cloak operating at optical frequencies. The principle and structure of the proposed cylindrical cloak are analysed, and the general recipe for the implementation of such a device is provided.

/pdf/optical-cloaking-with-metamaterials-44hn07kw9x.pdf

Optical cloaking with metamaterials

The Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) is a two-wavelength polarization lidar that performs global profiling of aerosols and clouds in the troposphere and lower stratosphere. CALIOP is the primary instrument on the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite, which has flown in formation with the NASA A-train constellation of satellites since May 2006. The global, multiyear dataset obtained from CALIOP provides a new view of the earth’s atmosphere and will lead to an improved understanding of the role of aerosols and clouds in the climate system. A suite of algorithms has been developed to identify aerosol and cloud layers and to retrieve a variety of optical and microphysical properties. CALIOP represents a significant advance over previous space lidars, and the algorithms that have been developed have many innovative aspects to take advantage of its capabilities. This paper provides a brief overview of the CALIPSO mission, the CA...

Overview of the CALIPSO Mission and CALIOP Data Processing Algorithms

In the laser Doppler and phase Doppler techniques a part of the incident laser light is imaged by the particles onto the detectors. It is this scattered light which carries information about the particle velocity and its properties and thus, the light scattered from small particles plays a central role in the basic physics of these measurement techniques. In recognition of this, the following chapter is devoted to the fundamentals of elastic light scattering from small particles. The simplest case of a homogeneous and isotropic sphere is considered.

Light Scattering from Small Particles

Preface.- Introduction.- Basic Measuring Principles.- Fundamentals of Light Propagation and Optics.- Light Scattering from Small Particles.- Signal Generation in Laser Doppler and Phase Doppler Systems.- Signal Detection, Processing and Validation.- Laser Doppler Systems.- Phase Doppler Systems.- Further Particle Sizing Methods Based on the Laser Doppler Technique.- Fundamentals of Data Processing.- Processing of Laser Doppler Data.- Processing of Phase Doppler Data.- Choice of Particles and Particle Generation.- System Design Considerations.- Appendix.- Bibliography.- Index.

Laser Doppler and Phase Doppler Measurement Techniques

The scattering properties of spherical particles crossing a laser beam deviate from the Lorenz-Mie solution for particles both smaller and larger than the beam dimensions. For smaller particles the local beam properties at the position of the particle can be used in the Lorenz-Mie calculations, whereas for larger particles the varying beam properties over the surface of the particle must be accounted for. The Fourier Lorenz-Mie theory and the extended geometrical optics theory offer two methods for analysing such situations. These two methods are used to investigate the scattering fields of various scattering particles and to demonstrate the agreement of the results. The results are useful for understanding the signal origins in laser-Doppler and phase-Doppler techniques, especially the `trajectory effect' or `Gaussian beam effect'.

The imaging properties of scattering particles in laser beams

Laser-Doppler-Strömungsmessung

The signal of a laser Doppler or phase Doppler system originates from the superposition of two scattered waves, emanating from a scattering center in the detection volume onto the photodetector. The description of these waves for an arbitrarily placed detector in space will now be examined in more detail.

H.-E. Albrecht

Papers

Light Scattering from Small Particles

Laser Doppler and Phase Doppler Measurement Techniques

The imaging properties of scattering particles in laser beams

Laser-Doppler-Strömungsmessung

Signal Generation in Laser Doppler and Phase Doppler Systems