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An analytical formalism of laser absorption in a nanorod embedded dielectric surface has been developed. Nanorods lie in the plane of the dielectric, in the form of a planar array. A laser, impinged on them with an electric field perpendicular to the lengths of the nanorods, imparts oscillatory velocity to nanorod electrons. As the free electrons of a nanorod are displaced, a space charge field is developed in the nanorod that exerts restoration force on the electrons and their drift velocity shows a resonance at ${\rm \omega} = {\rm \omega} _{\rm p}/\sqrt 2 $, where ωp denotes the plasma frequency of free electrons inside the nanorod. It is inhibited by collisions and nanorod expansion. At the resonance, the electrons are efficiently heated by the laser and laser energy is strongly absorbed, resulting in significant reduction in laser transmissivity. The transmissivity decreases with laser intensity.

In the present investigation, a high intense ultra-short pulse configuration has been proposed for plasma induced THz generation in carbon nano tubes. When a high intense ultra-short electromagnetic wave interacts with the periodically structured carbon nano tubes possessing second order susceptibility, the electromagnetic wave imparts oscillatory velocities to electrons that produce the heat. The generation of excess heat may deform the structure of the carbon nano tubes which lead to the reduction in the efficiency of THz generation. Therefore, the pulse parameters evolution such as normalized energy of the pulse, pulse width, position of the pulse center and reflectivity coefficient of the medium is investigated theoretically on plasma generation. The outcome of the theoretically investigated reveals that the increment in the heating rate can be caused by decrease in the pulse width, increment in reflectivity coefficient and the pulse peak power. Finally, an array of ultra-short pulse configurations has been proposed for efficient THz generation. The present work is helpful to regulate the heating of nanostructure during ultra-short pulse interaction.

A magnetized plasma embedded with clusters offers an efficient way to second harmonic generation by intense short pulse laser. An X-mode laser exerts second harmonic pondermotive force on cluster electrons and produces a nonlinear current, driving the second harmonic radiation. In the process of hydrodynamic expansion of clusters, the electron plasma frequency passes through the surface Plasmon resonance, leading to resonant enhancement in the harmonic yield. The magnetic field shifts the Plasmon resonance. For typical parameters one may achieve power conversion efficiency of a few percent at normalized laser amplitude to (electron drift velocity of speed of light) of 0.1.

A scheme of terahertz generation, employing carbon nanotubes (CNTs) embedded metal surface is proposed. The surface is irradiated by two laser beams at angle of incidence θ. The lasers exert a ponderomotive force on CNT electrons at the beat frequency ω=ω1-ω2 and produce a nonlinear current, turning the nanotubes into an array of antennae emitting beat frequency THz radiation. The THz field is resonantly enhanced at the plasmon resonance, ω = ω p β / 2 , where ωp is the plasma frequency of the CNT electrons and β is a parameter that characterizes the metallic susceptibility of the CNTs. The collisions are a limiting factor and cause heating of CNTs.

A scheme of terahertz radiation generation employing a matrix of anharmonic carbon nanotubes (CNTs) embedded in silica is proposed. The matrix is irradiated by two collinear laser beams that induce large excursions on CNT electrons and exert a nonlinear force at the beat frequency ω = ω1−ω2. The force derives a nonlinear current producing THz radiation. The THz field is resonantly enhanced at the plasmon resource, ω = ω p ( 1 + β ) / 2, where ωp is the plasma frequency and β is a characteristic parameter. Collisions are a limiting factor, suppressing the plasmon resonance. For typical values of plasma parameters, we obtain power conversion efficiency of the order of 10−6.