Shaojun Fu

Measurements of groove density for concave gratings with the long trace profiler

A long trace profiler method has been developed to measure the groove density of concave gratings in National Synchrotron Radiation Laboratory recently. With the aid of large angular acceptance (35mrad), it is suitable for precise measurement of concave or convex gratings with high curvatures. The effects of the slope variations along its substrate are discussed in detail. To eliminate the off-axis errors, which are the essential error sources in the measuring system based on rotating mounts of gratings, an error-reduced method is introduced consequently. A commercially available concave grating with a curvature radius of 998mm is measured and the relative groove density error δN∕N is about 4×10−5 rms.

Generalized groove density equation concerning bending-grating-related imaging properties

Varied-line-spacing gratings are used in soft-x-ray monochromators and spectrometers because of their ability to correct various aberrations by varying the groove density. A curved grating blank in a Rowland circle mounting could eliminate primary aberrations. Bending a plane constant-groove-density grating into a desirable surface can eliminate higher-order aberrations as a result of the change in surface profile and groove density. This provides a simple means for improving the imaging properties. When used in a monochromator, the grating can be bent to different degrees to minimize aberrations at all wavelengths. General formulas concerning the transformations of groove function, groove density, and groove spacing are presented for the bending grating. Analytic results with a numerical example show the significant properties of the system.

Design and fabrication of condenser zone plates for a soft x‐ray microscopy beamline in Hefei

A synchrotron radiation soft x‐ray beamline for scanning microscopy mainly, is being constructed in Hefei. It contains a linear monochromator consisting of a diaphragm of 7 μm diameter and one of three condenser zone plates (CZP). The three CZPs are for three overlapping wavelength ranges 1.97–2.78 nm (CZP23), 2.74–3.87 nm (CZP32), and 3.84–5.44 nm (CZP45), respectively. The processing steps for the condenser zone plate fabrication are summarized, especially the holographic exposure with a special optical system as a key step. Parameters of a prototype of CZP45 fabricated in Hefei are the following: D=2.9 mm, n=826, R1=0.05 mm, and ΔRn≊0.9 μm.

Microtribiology and self-lubrication microsystems

The microtribology phenomena on the micro contact (or slide) surface, where the effects of surface forces are more significant than those of gravity, is very different with the conventional machine. The friction force that works on a friction face of a microsystems is significantly high relative to the size of the machine, the fluid lubrication in the conventional size mechanical parts cannot reduce the friction force on the microsystems, the solid lubrication (self- lubrication) should be applied to reduce the friction force. In this paper, the solid lubrication MoS2 was studied. MoS2 is embedded into the Ni structure in electroforming process. The results show that MoS2 can be used as the solid lubrication in the microsystems to reduce the friction force and enhance the hardness of microsystem.

Manufacturing technology by synchrotron radiation in NSRL

In this paper a brief description is given to introduce the activities of the manufacturing technology using the synchrotron radiation light source in the National Synchrotron Radiation Laboratory (NSRL). The light source in NSRL is a dedicated synchrotron radiation facility in China. Five beamlines and corresponding experimental stations, including soft x-ray lithography, have been constructed. The main experimental results obtained from the soft x-ray lithography station are reported. We have fabricated some devices using the synchrotron radiation lithography, for example, the high electron mobility transistor, high Tc superconductor infrared detector-array, diffraction grating, and micro condenser zone plate. A simple method for the achievement of synchrotron radiation x-ray lithography mask will also be presented. The LIGA (German abbreviation for: Lithograpie, Galvanoforming, and Abforming) technique has been developed in NSRL. It is the most promising technique for the fabrication of three-dimensional microstructures. We are successful in making several microdevices by deep x-ray lithography and microelectroforming, such as microgearwheel, micro acceleration sensor.

Optics on a synchrotron radiation soft X-ray microscopy beamline and its dispersing components in Hefei

A modified optical design for a synchrotron radiation (SR) soft X-ray scanning microscopy beamline at Hefei National Synchrotron Radiation laboratory (HESYRL) has been done. On the beamline the main component is a linear monochromator which consists of a diaphragm with a diameter of 7 ?m and a condenser zone plate (CZP). The CZP is selected from among three condenser zone plates with different parameters for the following three overlapping wavelength ranges: 1.97-2.78 nm, 2.74-3.87 nm, and 3.84-5.44 nm. Estimating the flux losses from the pinhole source to the end spot for 2.3 nm, for example, a photon flux of 3.1 ? 105 photons/s can be achieved at the end spot from a 150 mA current and a high brightness configuration at HESYRL. Parameters of three kinds of CZPs are presented as a compromise to a variety of requirements from the experimenters. In addition, the thickness of some CZP layers, such as polyimide and gold, are calculated to be optimal. Finally, the processing steps for CZP fabrication at HESYRL are described briefly.

Development Of High Resolution Zone Plate By Holography And Ion-Etching Techniques

The purpose of development and the processing steps to fabricate high resolution zone plates, especially holographic exposure and ion-etching, are described. Also the experimental results and some prospects are presented.

Preliminary Optical Design Of An Imaging Soft X-Ray Microscopy (IXM) Beam Line And Fabrication Of Zone Plates In Hefei

A design of an optical system for testing zone plates by imaging with soft x-ray microscope is presented. The progress of zone plates fabrication in Hefei is also described. Finally, some aspects of our future plan are mentioned too.

An improved optical design for a microscopy beam line at Hefei

Abstract An improved optical design for a microscopy beam line at Hefei is presented, utilizing a linear monochromator which consists of a diaphragm and a condenser zone plate selected from several ones with different parameters for different wavelength ranges. The progress and plan for the construction of these condenser zone plates are also described.