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We exploit theoretically nonlinear optical materials by graded multilayered colloidal crystals, whose basic layer is made of metallodielectric nanoparticles immersed periodically in a host fluid. In the crystals, either the volume fraction of nanoparticles or the dielectric constant of host fluid can vary gradually within layers. The electric field distribution can be shown to exhibit a peak in a certain layer, and that the position of the peak can change by tuning the incident angular frequency. Such a gradation-controlled electric field distribution serves as a physical mechanism for understanding the enhanced nonlinear optical responses with a broad plasmon band. [ABSTRACT FROM AUTHOR]

Based on nonlinear composite materials, we exploit theoretically a class of electrically tunable one-dimensional double-layer photonic crystals (PCs), namely, composite-dielectric and composite-composite PCs. For such PCs, extensive and precise tunability of photonic band gaps can be readily achieved by choosing appropriate pump ac or dc electric fields. [ABSTRACT FROM AUTHOR]

The authors theoretically exploit a class of nonlinear optical materials, which are made of single domain ferromagnetic nanoparticles coated by a nonmagnetic nanoshell with an intrinsic second-harmonic generation (SHG) susceptibility in a nonmagnetic host fluid. The SHG of such materials possess magnetic-field controllabilities, i.e., magnetic-field-controllable anisotropy, redshift, and enhancement, which are caused to appear by the shift of a resonant plasmon frequency due to the formation of the chains of the coated nanoparticles. [ABSTRACT FROM AUTHOR]

We theoretically exploit a class of colloidal-crystal-based nonlinear optical materials, which are made of graded metallodielectric nanoparticles suspended in a host fluid. Such materials can have both an enhancement and a redshift of optical nonlinearity, due to the gradation inside the nanoparticles as well as the lattice effects arising from the periodic structure. [ABSTRACT FROM AUTHOR]

A correction to the article "Magneto-controlled nonlinear optical materials" that was published in the 2005 issue is presented.

An object exhibits the infrared thermogram of another object, which is called thermal illusion as extensively investigated in the field of thermal metamaterials. However, almost all the existing thermal illusion behaviors were theoretically designed by using unconventional thermal conductivities, which means that the conductivities must be anisotropic, graded, or even singular due to the analytical methods in use. This problem largely limits fabrications for applications. By suggesting two discretization steps, here we put forward a numerical method instead to design thermal illusion, for which unconventional conductivities are no longer needed. In the meantime, more importantly, we reveal different thermal illusion behaviors. By tailoring the joint effects of thermal conduction and convection, we design a thermal pixel of cuboidal shape. We show that the assembly of such pixels into different two-dimensional arrays could generate infrared thermograms of different objects, which is thus called the digital thermal metasurface. Also, the metasurface is reconfigurable, and it can apparently produce all the existing thermal illusion behaviors reported in the literature. Finally, we experimentally fabricate a prototype. This work opens a door for applying conventional thermal conductivities of commercially available materials to thermal illusion, and we expect it to stimulate more exciting developments in electromagnetic disguise and confrontation. [ABSTRACT FROM AUTHOR]

Thermal metamaterials have been applied to implement thermal phenomena, such as invisibility, illusion, and refraction. However, during the fabrication, they probably have complicated issues which are on account of the complicated structures. To get around this, here we put forward a single-particle structure. The theory helps to simplify the existing methods, which will undoubtedly contribute to the efficiency of fabrication. For clarity, we show the simulation and experimental results of thermal invisibility and illusion based on our proposed single-particle structural materials. Moreover, by tailoring the shape factor of the single particle appropriately, we can simultaneously realize thermal invisibility and illusion with only one device. The adjustable area fraction also indicates that these types of structural materials are highly adaptable. Such a single-particle device may have broad applications in misleading infrared detection. This work not only opens an avenue to design thermal materials based on single-particle structures but also holds for other physical fields like electrostatics, magnetostatics, and particle dynamics. [ABSTRACT FROM AUTHOR]

We develop two energy methods to investigate interparticle forces in a chain of three microparticles in an electric field, two of which are fixed and symmetrically located in the two opposite sides of the third free microparticle. We reveal that, if the free microparticle is laterally dragged and released, it can oscillate perpendicular to the line joining the centers of the two fixed microparticles, being in simple harmonic oscillation with a fixed period for small oscillation amplitudes. This work demonstrates that microparticles can be used to record time, which makes it possible to design a new class of microparticulate clocks. [ABSTRACT FROM AUTHOR]