Weak Antilocalization and Anisotropic Magnetoresistance as a Probe of Surface States in Topological BiTeSe Thin Films.

Topological materials, such as the quintessential topological insulators in the BiX family (X = O, S, Se, Te), are extremely promising for beyond Moore's Law computing applications where alternative state variables and energy efficiency are prized. It is essential to understand how the topological nature of these materials changes with growth conditions and, more specifically, chalcogen content. In this study, we investigate the evolution of the magnetoresistance of BiTeSe for varying chalcogen ratios and constant growth conditions as a function of both temperature and angle of applied field.

Three-dimensional analysis of subwavelength diffractive optical elements with the finite-difference time-domain method.

We present a three-dimensional (3D) analysis of subwavelength diffractive optical elements (DOE's), using the finite-difference time-domain (FDTD) method. To this end we develop and apply efficient 3D FDTD methods that exploit DOE properties, such as symmetry. An axisymmetric method is validated experimentally and is used to validate the more general 3D method.

Optical absorption modeling of thermal infrared detectors by use of the finite-difference time-domain method.

The optical absorption of thin-film thermal infrared detectors was calculated as a function of wavelength, pixel size, and area fill factor by use of the finite-difference time-domain (FDTD) method. The results indicate that smaller pixels absorb a significantly higher percentage of incident energy than larger pixels with the same fill factor. A polynomial approximation to the FDTD results was derived for use in system models.