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We have systematically investigated ultrathin Cr/Sc multilayers (nanolayers), using tunable soft-x-ray synchrotron radiation. The multilayers were optimized for use either in normal incidence or at 45 degrees at photon energies around the 2p-absorption edges of Sc (399 eV) and Cr (574 eV), respectively. They were sputter deposited on Si wafers or on thin Si(3)N(4)-membrane support structures for use in reflection and in transmission, respectively, as polarizing and phase-retarding elements in a polarimeter. The performance theoretically expected with respect to reflection/transmission and energy resolution has been confirmed experimentally: A value of 7% for the normal-incidence peak reflectance at 395 eV was measured as well as a pronounced minimum in transmission for certain incidence angles and energies below the respective absorption edges, indicating significant phase-shifting effects.

We provide an analysis of contemporary multilayer optics for extreme ultraviolet (EUV) solar astronomy in the wavelength ranges: λ=12.9-13.3  nm, λ=17-21  nm, λ=28-33  nm, and λ=58.4  nm. We found new material pairs, which will make new spaceborne experiments possible due to the high reflection efficiencies, spectral resolution, and long-term stabilities of the proposed multilayer coatings. In the spectral range λ=13  nm, Mo/Be multilayer mirrors were shown to demonstrate a better ratio of reflection efficiency and spectral resolution compared with the commonly used Mo/Si. In the spectral range λ=17-21  nm, a new multilayer structure Al/Si was proposed, which had higher spectral resolution along with comparable reflection efficiency compared with the commonly used Al/Zr multilayer structures. In the spectral range λ=30  nm, the Si/B₄C/Mg/Cr multilayer structure turned out to best obey reflection efficiency and long-term stability. The B₄C and Cr layers prevented mutual diffusion of the Si and Mg layers. For the spectral range λ=58  nm, a new multilayer Mo/Mg-based structure was developed; its reflection efficiency and long-term stability have been analyzed. We also investigated intrinsic stresses inherent for most of the multilayer structures and proposed possibilities for stress elimination.

We present research investigations in the eld of multilayer optics in X-ray and extreme ultra-violet ranges (XUV), aimed at the development of optical elements for applications in experiments in physics and in scienti c instrumentation. We discuss normal incidence multilayer optics in the spectral region of \water window", multilayer optics for collimation and focusing of hard X-rays, multilayer dispersing elements for X-ray spectroscopy of high-temperature plasma, multilayer dispersing elements for analysis of low Z-elements. Our research pays special attention to optimization of multilayer optics for projection EUV-lithography ( ¶ = 13nm) and short period multilayer optics.

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The main problems and the approach used by the authors for roughness metrology of super-smooth surfaces designed for diffraction-quality X-ray mirrors are discussed. The limitations of white light interferometry and the adequacy of the method of atomic force microscopy for surface roughness measurements in a wide range of spatial frequencies are shown and the results of the studies of the effect of etching by argon and xenon ions on the surface roughness of fused quartz and optical ceramics, Zerodur, ULE and Sitall, are given. Substrates of fused quartz and ULE with the roughness, satisfying the requirements of diffraction-quality optics intended for working in the spectral range below 10 nm, are made.

A prospective move to 10.5 and 11.2 nm wavelengths, as an alternative to 6.7 and 13.5 nm, for next generation nanolithography is discussed. Ten-mirror optical systems based on Ru/Be, Mo/Be, Rh/Sr, Mo/Si, and La/B multilayers were compared for efficiency at their working wavelengths. It is shown that a transition to 10.5 nm and 11.2 nm may be a solution to the problem of increasing performance and resolution of a projection system