870 research outputs found
(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
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