Tailoring 2D phononic crystal sensor properties by lattice symmerty reduction

We propose a novel method of tailoring the band structure of 2D phononic crystals (PnC) by reducing the lattice symmetry. Specifically, symmetry reduction by stretching and distorting the crystal face is explored. The transmission spectrum of the PnC was numerically calculated using the layer multiple-scattering method. Change in the shape and size of the band gaps is demonstrated as well as form of pass bands inside the stop band. The practical feasibility of the PnC sensor concept was evaluated for the case of synthetic quartz matrix and water inclusions. A distinct pattern of the pass band transformation inside the stop band which is induced by changing the distortion angle was demonstrated. The approach is in particular useful in adjusting the size and position of the gap and tailoring the size and position of the pass band in PnC sensors

Rotational and rotationless states of weakly-bound molecules

By making use of the quantization rule of Raab and Friedrich [P. Raab and H. Friedrich, Phys. Rev. A 78, 022707 (2008)], we derive simple and accurate formulae for the number of rotational states supported by a weakly-bound vibrational level of a diatomic molecule and the rotational constants of any such levels up to the threshold, and provide a criterion for determining whether a given weakly-bound vibrational level is rotationless. The results depend solely on the long-range part of the molecular potential and are applicable to halo molecules.Comment: slightly corrected version, 4 pages, 1 figure, 3 table

Interstellar Scintillations of Polarization of Compact Sources

We demostrate that the measurement of fluctuations of polarization due to the galactic interstellar scintillations may be used to study the structure of the radiation field at compact radio sources. We develop a mathematical formalism and demonstrate it on a simple analytical model in which the scale of the polarization variation through the source is comparable to the source size. The predicted amplitude of modulation of the polarized radiation flux is ~20% x (pi_s) x (m_sc), where (pi_s) is the characteristic degree of polarization of radiation at the source and (m_sc) is the typical modulation index due to scattering, i.e., (m_sc)~1 for diffractive scintillations and (m_sc)<1 for refractive scintillations.Comment: 5 pages, 2 figures, emilateapj.sty. Submitted to ApJ

Current status of metric reduction of (passive) scanner data

The extraction of metric information from scanner (particularly multispectral) data is presented. Data from both aircraft and spacecraft; singly scanned areas and areas with multiple coverage; various mathematical models used up to the present time; and published numerical results are considered. Future trends are also discussed