The history of multilayer mirrors for soft x-ray optics is briefly reviewed. This introduces the history of fabrication techniques, evaluation technique, improvement of multilayer performance, applications and x-ray optical devices in the first and second stage (1970-1990) of “modern multilayer era”.

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The history of multilayer mirrors for soft x-ray optics from the late 1980's to the present is briefly reviewed. This introduces the history of fabrication techniques, improvement of multilayer performance, applications and x-ray optical devices, adding these introduces future trends and future plans of several researchers.

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A new approach to the fabrication of multilayer mirrors on an atomic scale at soft x-ray wavelengths is desired to overcome serious problems regarding scattering loss at the rough surface and interface of the multilayer. In this review, recent progress regarding novel approaches utilizing atomic layer deposition and atomic layer epitaxy to the fabrication of multilayer structures for soft x-ray wavelengths is detailed. These novel approaches are expected to solve the above-mentioned problems and take the place of conventional sputtering methods because of their control performance of the surface on an atomic scale through their self-limiting functions.

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The recent progress of multilayers makes it possible to construct variety of optical systems used in the wavelength region 30-0.01nm. Especially a depth-graded multilayer, so called supermirror, has a great advantage to get high reflectivity in the wide energy band for hard x-rays. The design, fabrication and characterization of supermirror are going on to apply for synchrotron radiation beamline optics, x-ray telescope and x-ray microscope. At present reflectivity of Pt/C supermirror is obtained to be 20-30% in 27-40keV region at the incidence angle of 0.3deg..

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With use of synthetic microstructures as a mirror, multilayer polarizers have been developed for control and measurement of polarization in the soft x-ray region. The same structures made into free-standing transmission elements, showed good polarization performance. These new polarizing elements are evaluated in refering to the measured data. Some examples of forefront application of the polarizing elements are reviewed.

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Multilayer coated gratings have been developed in order to increase the diffraction efficiency without astigmatism which is available for smaller optical systems at (near) normal incidence in soft x-ray and EUV region. This technique has been studied firstly in the field of the astronomy, and the efficiency of the multilayer coated gratings have been improved to be much higher than that of the conventional gratings with monolayer metal film coating. Recently there are many studies to improve the diffraction efficiency and to solve the technical problems such as the roughness of the grating facets.

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Fresnel zone plates (ZP's) are now widely used as imaging or focusing optical devices in soft x-ray region. They are fabricated by the semiconductor technology. Since the ideal spatial resolution is almost equal to the outermost zone width, the progress of ZP's completely depends on that of fabrication technology of the ultra-fine structures. The outermost zone width has recently reached 20-30nm. One of the popular applications of the ZP's is to the x-ray microscope. Along with the recent progress in synchrotron radiation sources and laboratory-size laser produced plasma x-ray sources, many x-ray microscopes are in operation or under construction in the world. In this paper, the optical property of ZP's and the present status of the applications are briefly described.

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Ultraviolet laser ablation of lipid has been investigated. ArF, KrF and XeC1 excimer lasers have been adopted in this study. A fresh suet is used as the tissue sample. Ablation capability of the KrF laser was remarkably better than that of other lasers. Ablation threshold of the ArF laser was lower by six hold than that of the KrF laser. The ArF laser, however, did not efficiently ablate the suet at high-energy fluence due to spallation. The XeCI laser had poor ablation capability. These results suggest that the KrF laser is the most suitable laser for ablation of lipid.

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