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Wei J, Olaya D, Karasik BS, Pereverzev SV, Sergeev AV, Gershenson ME. Ultrasensitive hot-electron nanobolometers for terahertz astrophysics. Nature Nanotech. 2008;3(8):496–500.
Abstract: The submillimetre or terahertz region of the electromagnetic spectrum contains approximately half of the total luminosity of the Universe and 98% of all the photons emitted since the Big Bang. This radiation is strongly absorbed in the Earth's atmosphere, so space-based terahertz telescopes are crucial for exploring the evolution of the Universe. Thermal emission from the primary mirrors in these telescopes can be reduced below the level of the cosmic background by active cooling, which expands the range of faint objects that can be observed. However, it will also be necessary to develop bolometers – devices for measuring the energy of electromagnetic radiation—with sensitivities that are at least two orders of magnitude better than the present state of the art. To achieve this sensitivity without sacrificing operating speed, two conditions are required. First, the bolometer should be exceptionally well thermally isolated from the environment;
second, its heat capacity should be sufficiently small. Here we demonstrate that these goals can be achieved by building a superconducting hot-electron nanobolometer. Its design eliminates the energy exchange between hot electrons and the leads by blocking electron outdiffusion and photon emission. The thermal conductance between hot electrons and the thermal bath, controlled by electron–phonon interactions, becomes very small at low temperatures (10-16 WK-1 at 40 mK). These devices, with a heat capacity of 10-19 J K-1, are sufficiently sensitive to detect single terahertz photons in submillimetre astronomy and other applications based on quantum calorimetry and photon counting.
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Li M, Pernice WHP, Xiong C, Baehr-Jones T, Hochberg M, Tang HX. Harnessing optical forces in integrated photonic circuits. Nature. 2008;456(7221):480–4.
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Kopp VI, Churikov VM, Genack AZ. Chiral-fiber gratings sense the environment. In: Laser Focus World. Vol 44.; 2008. p. 76–9.
Abstract: The article focuses on the use of chiral fiber gratings in sensing. It discusses the production of chiral optical fibers which are created through twisting fibers. It cites experiments concerning the function of chiral-fiber grating produced by twisting optical fibers. The process and results of the experiments are also discussed in the article.
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Polyakova ON, Tikhonov VV, Dzardanov AL, Boyarskii DA, Gol’tsman GN. Dielectric characteristics of ore minerals in a 10–40 GHz frequency range. Tech Phys Lett. 2008;34(11):967–70.
Abstract: A new approach to investigation of the complex dielectric permittivity of both nonmetallic and ore minerals in the microwave frequency range is proposed. Using this approach, data on the complex permittivity of sphalerite, magnetite, and labradorite in a 10–40 GHz frequency range have been obtained for the first time. A method is proposed for calculating the complex permittivity from experimentally measured frequency dependences of the reflection and transmission coefficients of a plane-parallel plate of a given mineral. Approximate expressions that can be used for calculations of the complex refractive index and permittivity of minerals are presented.
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Tikhonov VV, Polyakova ON, Gol’tsman GN, Dzardanov AL, Boyarskiy DA. Determination of dielectric properties of ore minerals in the microwave band. Radiophys Quant Electron. 2008;51(12):966–74.
Abstract: We consider a method for determining the complex dielectric permittivity of ore and nonmetal minerals in the microwave band of electromagnetic radiation. The results of measuring the reflectivity and transmittivity of chalcopyrite, magnetite, sphalerite, and labradorite samples in the frequency range 77–300 GHz are presented. A method for calculation of the complex dielectric permittivity of minerals on the basis of the obtained experimental data is proposed. The approximation formulas for calculation of the complex dielectric permittivity of the studied minerals are given.
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