(1R,2R)-1,2-Diphenyl-1,2-bis­(1H-tetra­zol-1-yl)ethane

The title compound, C16H14N8, is a new chiral ligand designed for applications in supra­molecular chemistry and Fe2+ spin-crossover complexes. The crystal structure shows a herring-bone arrangement of the mol­ecules, which are mutually linked via inter­molecular C—H⋯N inter­actions mainly donated by the alkyl and tetra­zole H atoms

Broadband multi-layer anti-reflection coatings with mullite and duroid for half-wave plates and alumina filters for CMB polarimetry

A broadband two-layer anti-reflection (AR) coating was developed for use on a sapphire half-wave plate (HWP) and an alumina infrared (IR) filter for cosmic microwave background (CMB) polarimetry. Measuring tiny CMB B-mode signals requires maximizing the number of photons reaching the detectors and minimizing spurious polarization due to reflection with an off-axis incident angle. However, a sapphire HWP and an alumina IR filter have high refractive indices of about 3.1, and an AR coating must be applied to them. Thermally sprayed mullite and Duroid 5880LZ were selected in terms of index and coefficient of thermal expansion for use at cryogenic temperatures. With these materials, the reflectivity was reduced to about 2% at 90/150 GHz and <1% at 220/280 GHz. The design, fabrication, and optical performance evaluation of the AR coatings are described. The coatings were used in a current ground-based CMB experiment called the Simons Array. They could also be applied to next-generation CMB experiments, such as the Simons Observatory.Comment: 7 pages, 4 figure

Random phase-free kinoform for large objects

We propose a random phase-free kinoform for large objects. When not using the random phase in kinoform calculation, the reconstructed images from the kinoform are heavy degraded, like edge-only preserved images. In addition, the kinoform cannot record an entire object that exceeds the kinoform size because the object light does not widely spread. In order to avoid this degradation and to widely spread the object light, the random phase is applied to the kinoform calculation; however, the reconstructed image is contaminated by speckle noise. In this paper, we overcome this problem by using our random phase-free method and error diffusion method