Abstract

Through a high precision photo-acoustic device, we register the dichroic absorption of optical pulses crossing a structured device composed by an array of helices. The helices are grown upon a multilayered substrate of Al_0.3Ga_0.7N/GaN/AlN/Al₂O₃ and built with a focused ion-beam technique (FIBID). Helices are made up by a platinum-carbon (Pt-C) mixture with a percentage of C around 15% [1,2]. The array is of 12 μm x 12μm, composed of 16x16 units. The distance between adjacent helices is 700 nm, and their average diameter is approximately 300 nm (see Fig.1-left). The linear circular dichroism response of materials, i.e. the different response to input left and right circular polarized light, is associated to a different spatial distribution of electric currents, and to a consequently different absorption of light.

© 2015 IEEE