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An imaging x-ray microscope which can take an image by a short single x-ray pulse is important from the point of application for moving biological specimen and to avoid radiation damage [1]. In this paper the design of the optical arrangement of the practical compact imaging x-ray microscope which can take an image by a short single x-ray pulse by using a laser plasma source and a zone plate is presented based on the experimental results. The spatial resolution of 25 nm is feasible by a single x-ray pulse.

Soft x-rays generated from a laser produced plasma are of interest as a source for an x-ray microscope and also for x-ray lithography. In this paper, the x-ray generation from a recently developed, table-top high repetitive, high energy moving glass slab laser1) is demonstrated. The laser system can be operated at 5 Hz with laser pulse energy of 6 J. The size of the system is expected to be 3.4 m × 1.2 m × 1.3 m except for the power supply and the cooling unit.

A partial transmission Fresnel zone plate (PT-FZP), a new kind of modified zone plate, in which part of the normally transparent zones is transparent, is proposed. The resolution of PT-FZP is shown to be nearly the same to that of the normal zone plate. In PT-FZP, the distance between transparent zones can be set large so that a zone plate with very high resolution can be fabricated by electron beam lithography because the proximity effect due to electron scattering in a resist layer can be reduced. Part of the PT-FZP pattern of 100nm thick gold with a zone width of 25nm can be obtained by a 50keV electron beam exposure system.

Various kinds of high resolution techniques such as ion etching, chemical etching, ion implantation, and electron beam lithography are studied for fabricating CdTe optical integrated circuits. It is found that the ion-etching rate of CdTe is high and has only a small dependence on crystal orientation. A special chemical etching solution for aluminum on CdTe that does not corrode CdTe and proton implanted CdTe is used for high resolution patterning of CdTe. The smooth patterns in PMMA resist produced by an electron beam exposure is replicated deep into 2.5 μm of CdTe face through the aluminum layer. Rib guides and a rib-type optical directional coupler are fabricated from planar guides by using proton implantation which makes refractive index change on CdTe face. The two-dimensional optical confinement is observed. A coupling coefficient of k \simeq 0.39 mm-1is observed in the rib-type optical directional coupler.

Optical waveguides are formed by implantation of various ions (H+, H2+, He+, Li+, and B+) in fused quartz and the properties of mode propagation are investigated at 6328 A. The origin of the refractive index change is discussed from the ESR measurement. The depth distribution of defects is measured by ESR measurements and the effective thickness of the high-refractive index region is estimated from the measured depth distribution of defects. In as-implanted samples, the propagation loss decreases with decreasing fluence, but a minimum fluence is required for a given implantation energy for the lowest mode to be propagated. The propagation loss is explained to be internal absorption due to color centers introduced by ion implantation. It is shown that the propagation losses are different for various implanted ions. Annealing behavior of the propagation loss and the refractive index change is also presented.

Time delays of up to 500 nsec were observed in the stimulated emission of Cd-rich CdS crystals at 80° K pumped by an electron beam. The delay decreased with increase of excitation and the memory effect of the first pulse was observed for lasing during the second pulse when two separated electron-beam pulses (double pulse) were applied to the sample.

Time duration of the output pulse of electron-beam-pumped CdS laser was investigated. It increased with increase of the excitation current density and was of the order of 100 ns at the beam voltage of 25 kV. It was shown experimentally that the quenching of the laser oscillation is due to the rise of the threshold current density as the result of the temperature rise in the active region of the crystal. The expression for the duration of laser oscillation based on this model was derived and compared with the experimental results. The dependence of the duration on the excitation current density was explained by this model.

Synchrotron radiation from the electron‐synchrotron INS‐ES at the University of Tokyo has been used for x‐ray lithography. Several mask patterns, such as the bubble pattern and the holographic grating pattern, are duplicated. Masks used are 0.4 μm‐thick gold on 3‐μm silicon. At an electron energy of 1.1 GeV the direct‐total beam of synchrotron radiation can be used for mask replication. By using the grating‐mask pattern with 692‐nm period made by the holographic method, the grating pattern with a large height‐to‐width ratio is obtained. This result clearly demonstrates the high collimation of the x‐ray beam from the synchrotron.

The results of x‐ray lithography using the synchrotron radiation of the storage ring, SOR‐ring, at an electron energy of 0.3 GEV are studied. AIP

The ion implantation technique as fabrication method of optical waveguides has the following advantages: 1) the change of refractive index and its distribution can be controlled accurately by choosing the dose and the energy of implanted ions, 2) the higher refractive-index region can be buried in the interior of the substrate and the refractive index change is distributed along depth. Therefore, the scattering loss due to an imperfect interface at an abrupt boundary can be reduced. So far the formation of optical waveguides by ion implantation is realized1) in fused quartz, GaAs, CdTe, GaP and ZnTe. By using semiconductors there is a possibility of making an active optical circuits by this technique.

Intense soft x-ray generation in 1.05, 0.53, 0.26μm laser-produced plasmas has been investigated for the photon energies of 0.15 to 3keV. X-ray spectra and conversion efficiency are obtained as a function of atomic number. We find a parameter range of the target and laser conditions which allows us to achieve an adequate throughput of the exposure for x-ray lithography. X-ray lithography experiments using laser plasma x ray are presented. The facility consisting of a laser system and several exposure stations is proposed. Finally we propose the use of liquid or solid cryogenic targets of xenon or krypton to avoid the deposition of the target material. A preliminary experimental result and target schemes are presented.

A Fresnel zone plate, a focusing element that operates using diffraction, is a promising candidate for x‐ray optical elements since the index of refraction of all materials in this region is slightly less than unity. In this report, a new fabrication method for zone plates using electron beam lithography and reactive ion etching is described. By this method, it is possible to obtain a high resolution zone plate with a large aspect ratio. Focusing characteristics of fabricated zone plates are measured by synchrotron radiation. At the wavelength of 9 nm, the spot size of 2 μm is obtained at the focal point of 100 mm.