Raymond T. Perkins

18.3: Invited Paper: The Display Applications and Physics of the ProFlux™ Wire Grid Polarizer

Each year the Society awards the Display of the Year Award to several leading edge display devices or technologies that provide innovative solutions to an information display need. The following paper provides a summary of a 2001 Display of the Year award recipient. The new polarization technology described here enables new solutions to difficult and fundamental problems in the display industry. It is applicable and valuable in all types of Liquid-Crystal (LC) displays or other applications of polarization in information display technology.

Using thin film stress to produce precision, figured X-ray optics

We are studying the possibility of producing precision, aspherical mirrors for X-rays and visible light. Our study examines the use of ultrastructure processing to replace mechanical methods of material removal. The method starts with a chemically-mechanically polished, flat silicon wafer. The aim is to preserve atomic scale smoothness of the surface wafer while the wafer is bent to a desired figure. We report measurements of the mechanical properties of various stressing layers. This involves measuring the deformation of several thin silicon wafers coated with chemically vapor deposited nickel and boron films of known thickness. We have found that, under normal conditions, the film does not add to the microroughness of the substrate on either the front or the back surfaces. Film and substrate thicknesses, however, vary by as much as 10%. This is the present limit on figure accuracy. We have developed a model that describes bending of B/Si and Ni/Si structures. The model relates stress and Youngs modulus to the measured thickness of the film, and the thickness and curvature of the substrate. This approach is used to measure the stress and Youngs modulus for boron and nickel films. The Youngs modulus Ef was 3.05 x 1012 Pa for the boron films and 1.4 x 1010 Pa for the nickel films. From the relationship developed and verified for predicting the radii of curvature of the substrate, if may be possible to define a film thickness pattern which would provide a desired optical figure.

Fabrication process for multilayer x-ray phase gratings

This paper describes a fabrication method for making multilayer coated phase reflection gratings and arbitrary phase patterned reflection optics suitable for soft x-ray imaging. This represents an improvement over previous fabrication methods using anisotropic or ion-beam etching, which were limited to amplitude structures by the induced roughness on the etched portions of the substrate. Included also is a scalar model for multilayer phase grating reflectivity.

Design Of High Performance Soft X-Ray Windows

Methods of designing strong, high transmission soft x-ray windows are discussed. A material which contains several elements, most notably 0, N, and C, produce the most spectrally neutral window. It is noted that a predominantly single element material such as diamond is in reality an edge filter. A structure to support very thin films and to provide exceptional mechanical strength is discussed. Pressure cycling data for such a supported window are presented.

Design and fabrication of heat resistant multilayers

Many promising applications of multilayer x-ray optical elements subject them to intense radiation. This paper discusses the selection of optimal pairs of materials to resist heat damage and presents simulations of multilayer performance under extreme heat loadings.

Study Of Multilayers Subjected To Intense Radiation

Many promising applications of multilayer x-ray optical elements subject them to intense radiation. In this paper we present simulations of multilayer performance under extreme heat loads and preliminary results of robust multilayer characterization experiments.

Theoretical Considerations in the Design of Multilayer X-Ray Optics

There is increasing interest in the application of multilayers to figured x-ray optics. Two concepts in design approach are presented. The requirements for image formation with a multilayer device are discussed. A geometrical approach is used. The possible affect of multilayers on image quality are studied. Models for the reflectivity of x rays by multilayers are compared briefly.

Multilayer X-Ray Optics Produced By Atomic Layer Epitaxy

Thin film deposition techniques currently being used to produce multilayer x-ray optics (MXOs) have difficulty producing smooth, uniform multilayers with d-spacings less than about twelve angstroms. We are investigating atomic layer epitaxy (ALE) as an alternative to these techniques. ALE is a relatively new thin film deposition technique which we believe can produce MXOs with very small d-spacings. ALE accomplishes this by depositing a single layer of atoms during each cycle of the deposition process. Multilayers deposited by ALE should have sharp interfaces and smooth, uniform layers with precise d-spacings.

Optical Elements For Soft X Rays

X-rays present designers of optics with unfamiliar problems which are currently being solved in novel ways. Multilayer diffractors are an important new class of x-ray optics. Their advantages and limitations are discussed and a rational method for their design is presented.