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Graphene demonstrates superior electronic properties that make it a potential candidate for future electronic systems. Graphene, additionally, support surface plasmon oscillations, which in turn makes graphene at tractive for optoelectronics because of its planar structure and its conductivity properties. When a graphene layer is confined in one dimension, a graphene nanoribbon arises, with proerties differing from the original two dimensional graphene. In this paper we study the main properties of plasmon oscillations on metallic armchair graphene nanoribbons using the dielectric function obtained through the random phase approximation. We mainly study the effect of the graphene nanoribbon width on the plasmon propagation length using numerical techniques to extract the dispersion relation of graphene nanoribbons and the propagation properties of palsmons on graphene nanorib bons.

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A Blumlein based on helical line storage elements was conceived and developed for generation of a rectangular pulse of 150 kV, 5 μs duration and which can drive a load of about 1 kΩ impedance. The helical line consisting of an aluminum tube of 750 mm length and 100 mm diam, wound with mylar film insulation to withstand 200 kV and then wound with copper wire was built and tested in our laboratory. It has a capacitance of 1.2 nF and has a characteristic impedance of 2 kΩ. The pulse generator built here, uses ten such coils in Blumlein configuration with five elements in parallel in each section giving total capacitance of about 10 nF. It has the advantages of compactness, simplicity, low cost, reliability, and high performance towards good flat top, low rise time, and small jitter. It can be designed to match load impedances in the range of a few ohms to several kilo ohms. This pulse power system was built and successfully tested for accelerating electrons in the gun chamber of an electron beam controlled CO2 laser operating in the single shot mode. This article describes the design, fabrication, and performance of the pulse power system.