Measurement of Electrical Properties of Superconducting YBCO Thin Films in the VHF Range.

A new measurement technique of electrical parameters of superconducting thin films at the Very High Frequency (VHF) range is described, based on resonators with microstrip (MS) structures. The design of an optimal resonator was achieved, based on a thorough theoretical analysis, which is required for derivation of the exact configuration of the MS. A theoretical model is presented, from which an expression for the attenuation of a MS line can be derived.

Measuring the refractive index around intersubband transition resonance in GaN/AlN multi quantum wells.

We present the direct measurement of the refractive index distribution (spectral dispersion) arising from an intersubband transition in GaN/AlN multi quantum wells structure. The measurement is carried out through a novel interferometric technique. The measured interferogram yields a change in the refractive index varying from -5 × 10(-3) to 6 × 10(-3) as a function of the wavelength, introduced by the intersubband resonance at 1.