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We present a simple method of extracting a small number of reference optical turbulence and wind profiles from a large dataset for single conjugate and extreme adaptive optics simulations. These reference profiles can be used in slow…

Instrumentation and Methods for Astrophysics · Physics 2022-10-18 O. J. D. Farley

We calculate the index of refraction of sodium matter waves propagating through a gas of nitrogen molecules. We use a recent ab initio potential for the ground state of the NaN_2 Van der Waals complex to perform quantal close-coupling…

Atomic Physics · Physics 2015-06-12 J. Loreau , V. Kharchenko , A. Dalgarno

Layers with gradient refractive-index profile are an attractive alternative to conventional homogeneous stack coatings. However, the optical characterization and monitoring of the graded refractive-index profile is a complex issue, which…

Optics · Physics 2021-11-03 Vít Kanclíř , Jan Václavík , Karel Žídek

Near-future astronomical survey experiments, such as LSST, possess system requirements of unprecedented fidelity that span photometry, astrometry and shape transfer. Some of these requirements flow directly to the array of science imaging…

In this paper, we revisit a well-known formulation of temperature structure parameter ($C_T^2$), originally proposed by V.~I.~Tatarskii. We point out its limitations and propose a revised formulation based on turbulence variance and flux…

Atmospheric and Oceanic Physics · Physics 2021-10-08 Sukanta Basu , Albert A. M. Holtslag

In adaptive optics, the tracker and wavefront sensor commonly measure irradiance centroids (in their respective focal planes) to estimate the turbulence-degraded wavefront in the pupil plane. Several factors affect the accuracy of these…

Optics · Physics 2025-05-02 Milo W. Hyde , Eric W. Mitchell , Mark F. Spencer

The refractive index of single microparticles is derived from precise measurement and rigorous modeling of the stiffness of a laser trap. We demonstrate the method for particles of four different materials with diameters from 1.6 to 5.2…

Atmospheric optical turbulence seriously limits the performance of high angular resolution instruments. An 8-night campaign of measurements was carried out at the LAMOST site in 2011, to characterize the optical turbulence. Two instruments…

Instrumentation and Methods for Astrophysics · Physics 2015-05-21 L. -Y. Liu , C. Giordano , Y. -Q. Yao , J. Vernin , M. Chadid , H. -S. Wang , J. Yin , Y. -P. Wang

Cn2 profile monitoring usually makes use of wavefront slope correlations or of scintillation pattern correlations. Wavefront slope correlations provide sensitivity to layers close to the receiving plane. In addition, scintillation…

Instrumentation and Methods for Astrophysics · Physics 2015-03-17 Clélia Robert , Juliette Voyez , Nicolas Védrenne , Laurent Mugnier

We investigate the inverse source problem for the wave equation, arising in photo- and thermoacoustic tomography. There exist quite a few theoretically exact inversion formulas explicitly expressing solution of this problem in terms of the…

Analysis of PDEs · Mathematics 2018-08-01 Ngoc Do , Leonid Kunyansky

A new system, consisting of a double channel Fabry Perot etalon and laser diodes emitting around 780 nm is described and proposed to be used for air refractive index measurements. The principle of this refractometer is based on frequency…

Optics · Physics 2007-05-23 N. -E. Khélifa , H. Fang , J. Xu , P. Juncar , M. Himbert

The nonlinear optical response of materials under high-intensity electromagnetic fields is key to advancing THz optical technologies. This study introduces a theoretical approach to estimate the nonlinear refractive index coefficient n2 of…

First, we make a revision of the up-to-date Passive Scalar Fields properties: also, the refractive index is among them. Afterwards, we formulated the properties that make the family of `isotropic' fractional Brownian motion (with parameter…

Optics · Physics 2007-05-23 Dario G. Perez

The axial dependence of femtosecond filamentation in air is measured under conditions of varying laser pulsewidth, energy, and focusing f-number. Filaments are characterized by the ultrafast z-dependent absorption of energy from the laser…

The next generation of adaptive optics (AO) systems will require tomographic reconstruction techniques to map the optical refractive index fluctuations, generated by the atmospheric turbulence, along the line of sight to the astronomical…

Instrumentation and Methods for Astrophysics · Physics 2014-01-07 H. W. Shepherd , J. Osborn , R. W. Wilson , T. Butterley , R. Avila , V. S. Dhillon , T. J. Morris

We present a new method to calculate optical properties of strongly correlated systems. It is based on dynamical mean field theory and it uses as an input realistic electronic structure obtained by local density functional calculations.…

Strongly Correlated Electrons · Physics 2007-05-23 V. S. Oudovenko , G. Palsson , K. Haule , S. Y. Savrasov , G. Kotliar

New high-refractive-index dielectric materials may enhance many optical technologies by enabling efficient manipulation of light in waveguides, metasurfaces, and nanoscale resonators. Van der Waals materials are particularly promising due…

Riptide is a detector concept aiming to track fast neutrons. It is based on neutron--proton elastic collisions inside a plastic scintillator, where the neutron momentum can be measured by imaging the scintillation light. More specifically,…

One-dimensional optical waveguiding is revisited using the electromagnetic deduction of Fresnel formulas relating the incident, reflected, and transmitted waves on the abrupt interface between two different optical media. Throughout the…

The approximate nature of the adaptive-optics time constant measurements with MASS is examined. The calibration coefficient C derived from numerical simulations of polychromatic scintillation shows dependence on the height of the turbulence…

Instrumentation and Methods for Astrophysics · Physics 2015-03-17 Andrei Tokovinin
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