Chair of Microwave Engineering

photonic crystals

Measuring the Field Distribution of Photonic Crystals

Zwei Studenten und eine Tasse Kaffee

The Chair of Materials Science, Faculty of Engineering is concerned with the theoretical calculation of the field distribution of photonic crystals. For later applications, these are used in the optical frequency range and are made by etching directly on semiconductor substrates. However, it is difficult to verify in the optical wavelength range, the theoretically calculated field distribution measurements. For this reason, the Department of General Materials Science produced large photonic crystals of aluminum oxide bars, whose field distribution at the Institute of High Frequency Engineering at microwave frequencies is measured.

The measurements are performed in the anechoic chamber to minimize the influence of disturbing fields, as well as reflections on the walls. In the anechoic chamber is a computer-controlled assembly that allows placement of a probe field in all three spatial directions. Using a modulated signal source and a lock-in amplifier can detect the field distribution with a high dynamic range. The measurements were performed in the frequency range from 6 GHz to 12 GHz. Each frequency and polarization more than 22 thousand points were measured in a plane for detecting focusing points of the photonic crystal. The measurements are very time consuming and ongoing. At present, a crystal is studied, arranged in the alumina rods with a normally distributed impurity outside the ideal position in order to investigate the influence of manufacturing impurities on the effectiveness of the arrangement.



Dr.-Ing. Frank Daschner
Phone: 0431 / 880-6169

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