Time filter

Source Type

Tsai H.-M.,National formosa University | Liao C.,National formosa University | Liao C.,Advanced Research and Business Laboratory ARBL
Optical and Quantum Electronics | Year: 2016

Within man-made plasma sources, including the fusion experimental machines such as the Tokamaks, a phenomenon called the “Weibel EM instability” emerges at times. In all cases, such plasma instability constitutes a valid path for system energy loss, and thus is undesirable. Here, instead, a possibility is explored in which such instability is attempted for good use, viz, amplifying lightwaves in open space of arbitrary wavelengths and amplitudes. Obviously, this is to be compared with the traditional means via spatially-confined, wavelength-restricted erbium-doped optic fibers. The adopted approach here was to utilize artificial plasma in the controlled form of vertically oscillating (with respect to the intended incident light) electrons on a conductive grating. That is, free energy of the sloshing electrons was used to trigger Weibel type instability to act on the incident lightwave in the hope that exponential growth of the latter would occur. It turned out that the anticipated lighwave amplification in air was evidenced unambiguously by experiments with the aid of a lock-in amplifier. The desirable amplitude enhancement could have been one to two orders of magnitude, in principle, had the phasing, amplifier transparency been properly conditioned and arranged for the incident waves. However, to achieve these ambitious goals in the future, nontrivial tasks, especially phase synchronization among the plasma electrons and photons of different coherent wave packets, need to be accomplished in the first place. © 2016, Springer Science+Business Media New York. Source

Liao C.,National formosa University | Liao C.,Advanced Research and Business Laboratory ARBL | Yeh L.-S.,Advanced Research and Business Laboratory ARBL | Lai W.-B.,National formosa University | And 3 more authors.
Optical and Quantum Electronics | Year: 2016

In a source-free space, i.e., the classical vacuum, transverse-electro-magnetic (TEM) waves are spontaneous normal modes propagating within. Namely, a standard electromagnetic (EM) wave equation, in terms of either the electric or magnetic vector field, can be arrived at by combining Faraday’s and Ampere’s laws of Maxwell’s equations under the source-free condition. This implies that whenever there are electric charges, stationary or moving, the above EM or light waves have to be distorted in form (i.e., becoming driven modes at least), should their presence be still allowable in the now charged space. That is, electric charges may in fact be used to manipulate the formation, topology, transport and refractive manners of EM or light waves. One already well-acquainted example of such lightwave-influencing charges is passively bound charge carriers, or more precisely, the electric dipoles within optical dielectric materials in general. In this theoretical exploration, instead, attempt is aimed at electrically active charges which may be capable of affecting EM refractive properties, or maneuvering lightwaves in favorable ways to be exploited. It is noted that existing electronically-operated spatial light modulators, which mainly function through controlling liquid crystals, are irrelevant to this study. © 2016, Springer Science+Business Media New York. Source

Discover hidden collaborations