Tetsuji Onuki

Sub-100 nm-Resolution Grazing Incidence Soft X-Ray Microscope with a Laser-Produced Plasma Source

A high-resolution soft X-ray microscope was constructed using grazing incidence mirrors and a laser-produced plasma source. An Nd-YAG pulse laser (1.064 µm) was focused onto an aluminum target to produce soft X-rays above 4 nm in wavelength. The beam energy of the laser was 1.4 J, with a pulse width of 8 ns. The Wolter type-I mirror was used as an objective mirror and the toroidal mirror as a condenser. The magnification of the objective was 20. A holographic plate was used as a detector. Resolution of about 40 nm was achieved with a single shot.

Fabrication of Wolter type I mirror for soft x-ray

Soft X-ray microscopy, especially using the wavelength region from 2.4nxn to 4.4nxn, is expected in biology. Because the microstructure of live and thick biological specimens containing water can be observed by x-ray absorption difference of protein and water with low damage. The final goal of this work is to produce an imaging x-ray microscope for biological studies.

X-Ray Photoelectron Spectroscopy Using a Focused-Laser-Produced Plasma X-Ray Beam

The observation of X-ray photoelectrons induced by laser-produced plasma X-rays has been made for the very first time. Aluminum plasma X-rays were monochromatized to 5.25 nm (236 eV) using a multilayer mirror and focused to 50 µm×70 µm by the Wolter type-I mirror. Au(4f) and SiO2(2p) photoelectrons were observed with the hemispherical electrostatic electron energy analyzer. The multichannel detector has been used to detect the pulse photoelectrons of the required energy bands individually.

testing at 1nm accuracy for sub-mm asphericity

This paper describes null interferometry at 1nm accuracy for testing aspherical surfaces of sub-mm deviation from the best fitting sphere. We have developed the two kinds of null compensators. The one is a “null lens” composed of almost perfect spherical surfaces and homogeneous glass. The other is a “zone plate” manufactured through the lithography process. The results of the two null testing were compared with the results by the ultra-precision CMM (Coordinate Measuring Machine). These totally different measurements differed only by an amount of 1.6nm rms. This result shows the accuracy of our null interferometry is almost 1nm rms.

Interferometry with Null Optics for Testing Aspherical Surfaces at 1nm Accuracy

This paper describes null interferometry at 1nm accuracy for testing aspherical surfaces of sub-mm deviation from the best fitting sphere. We have developed the two kinds of null compensators. The one was the null lens composed of almost “perfect” spherical surfaces and homogeneous glass. The other was the zone plate manufactured through the lithography process. The measurement results using these null compensators were compared with the results by the ultra-precision CMM (Coordinate Measuring Machine). These three measurements differed only by an amount of 1.6nm rms. This result proved the accuracy of our null interferometry was almost 1nm rms.