Recent advances in X-ray refractive optics

Аристов, В. В.; Shabel'nikov, L.G.

doi:10.1070/pu2008v051n01abeh006431

Cited by 16 publications

(7 citation statements)

References 89 publications

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“…(2) In addition the interaction of electromagnetic waves with the medium and in other ranges can be described by the formula (2). For example artificial periodic structures -photonic crystals [8], objects of X-ray optics for soft X-rays [9] also formally correspond to (2) since the elements scattering radiation form a certain spatial structure.…”

Section: Laws To Change the Momentum And Energy Of The Fieldmentioning

confidence: 99%

Fundamental System of Equations for Momentum and Energy of Electromagnetic Field in Inhomogeneous Medium

Dyshekov¹

2019

RENSIT

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An alternative approach to the description of the interaction of the electromagnetic field with the crystal is proposed, in which the main characteristics are the energy and pulse densities. The reaction of the medium to the external perturbation is considered as a local change in geometry-the rotation of the orthogonal basis built on the induction vectors and the pulse of the field, determined by the structural characteristics of the medium. The equations that allow calculating the momentum and energy of the field in its interaction with the crystal are obtained.

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Section: Laws To Change the Momentum And Energy Of The Fieldmentioning

confidence: 99%

Fundamental System of Equations for Momentum and Energy of Electromagnetic Field in Inhomogeneous Medium

Dyshekov¹

2019

RENSIT

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“…For diffraction-limited telescope mirrors, the polished surfaces need to have surface smoothness < λ /4 (Danjon & Couder, 1935), which makes the production of telescopes for UV, X-ray and γ-ray increasingly difficult. Additionally, the refractive index of all known materials is close to 1 at high (keV) energies, making it difficult to focus photons efficiently and avoid absorption (Aristov & Shabel'nikov, 2008).…”

Section: Signal Lossesmentioning

confidence: 99%

Interstellar communication. I. Maximized data rate for lightweight space-probes

Hippke

2018

International Journal of Astrobiology

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Recent technological advances could make interstellar travel possible, using ultra-lightweight sails pushed by lasers or solar photon pressure, at speeds of a few percent the speed of light. Obtaining remote observational data from such probes is not trivial because of their minimal instrumentation (gram scale) and large distances (pc). We derive the optimal communication scheme to maximize the data rate between a remote probe and home-base. he framework requires coronagraphic suppression of the stellar background at the level of 10 −9 within a few tenths of an arcsecond of the bright star. Our work includes models for the loss of photons from diffraction, technological limitations, interstellar extinction, and atmospheric transmission. Major noise sources are atmospheric, zodiacal, stellar and instrumental. We examine the maximum capacity using the "Holevo bound" which gives an upper limit to the amount of information (bits) that can be encoded through a quantum state (photons), which is a few bits per photon for optimistic signal and noise levels. This allows for data rates of order bits per second per Watt from a transmitter of size 1 m at a distance of α Centauri (1.3 pc) to an earth-based large receiving telescope (E-ELT, 39 m). The optimal wavelength for this distance is 300 nm (space-based receiver) to 400 nm (earth-based) and increases with distance, due to extinction, to a maximum of ≈ 3 µm to the center of the galaxy at 8 kpc. 1

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“…Classical parabolic mirrors at these wavelengths suffer from low reflectivity, because the refractive index of most materials converges to unity at high (keV, λ ≈ nm) energies. This makes it difficult to focus photons efficiently and avoid absorption (Aristov & Shabel'nikov 2008), and it makes lenses impossible with known materials. Current limits at λ = 11 nm (extreme ultraviolet, EUV) and normal (not gracing) incidence angle are 80% reflectivity using exotic alloys (Singh & Braat 2000).…”

Section: Reflectivity At Nm Wavelengthsmentioning

confidence: 99%

Interstellar communication. III. Optimal frequency to maximize data rate

Hippke,

Forgan

2017

Preprint

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The optimal frequency for interstellar communication, using "Earth 2017" technology, was derived in papers I and II of this series (Hippke 2017a,b). The framework included models for the loss of photons from diffraction (free space), interstellar extinction, and atmospheric transmission. A major limit of current technology is the focusing of wavelengths λ < 300 nm (UV). When this technological constraint is dropped, a physical bound is found at λ ≈ 1 nm (E ≈ keV) for distances out to kpc. While shorter wavelengths may produce tighter beams and thus higher data rates, the physical limit comes from surface roughness of focusing devices at the atomic level. This limit can be surpassed by beam-forming with electromagnetic fields, e.g. using a free electron laser, but such methods are not energetically competitive. Current lasers are not yet cost efficient at nm wavelengths, with a gap of two orders of magnitude, but future technological progress may converge on the physical optimum. We recommend expanding SETI efforts towards targeted (at us) monochromatic (or narrow band) X-ray emission at 0.5-2 keV energies.

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Recent advances in X-ray refractive optics

Cited by 16 publications

References 89 publications

Fundamental System of Equations for Momentum and Energy of Electromagnetic Field in Inhomogeneous Medium

Fundamental System of Equations for Momentum and Energy of Electromagnetic Field in Inhomogeneous Medium

Interstellar communication. I. Maximized data rate for lightweight space-probes

Interstellar communication. III. Optimal frequency to maximize data rate

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