Characterization of the Uniformity of High-Flux CdZnTe Material.

Since the late 2000s, the availability of high-quality cadmium zinc telluride (CdZnTe) has greatly increased. The excellent spectroscopic performance of this material has enabled the development of detectors with volumes exceeding 1 cm3 for use in the detection of nuclear materials. CdZnTe is also of great interest to the photon science community for applications in X-ray imaging cameras at synchrotron light sources and free electron lasers. Historically, spatial variations in the crystal properties and temporal instabilities under high-intensity irradiation has limited the use of CdZnTe detectors in these applications. Recently, Redlen Technologies have developed high-flux-capable CdZnTe material (HF-CdZnTe), which promises improved spatial and temporal stability. In this paper, the results of the characterization of 10 HF-CdZnTe detectors with dimensions of 20.35 mm × 20.45 mm × 2.00 mm are presented. Each sensor has 80 × 80 pixels on a 250-m pitch and were flip-chip-bonded to the STFC HEXITEC ASIC. These devices show excellent spectroscopic performance at room temperature, with an average Full Width at Half Maximum (FWHM) of 0.83 keV measured at 59.54 keV. The effect of tellurium inclusions in these devices was found to be negligible; however, some detectors did show significant concentrations of scratches and dislocation walls. An investigation of the detector stability over 12 h of continuous operation showed negligible changes in performance.

Plasmonic Bragg reflectors for enhanced extraordinary optical transmission through nano-hole arrays in a gold film.

We demonstrate the use of plasmonic Bragg reflectors (PBRs) to enhance the extraordinary optical transmission (EOT) from an array of subwavelength apertures in a gold film. Arrays of partially milled lines and dimples are placed at the edges of an array of nano-holes in a gold film. These PBR structures, with half the pitch of the array, capture light scattered away from the array by Bragg reflection. By appropriate positioning of the PBR, the light is reflected in-phase with the EOT light and thereby doubles the EOT without shifting the wavelength of the resonant transmission peak. Furthermore, the PBR structures show strong polarization dependence that is also strongly dependent on the structure of the PBR, as explained in terms of scattering of the surface waves.