Light scattering from binary optics.

摘要

Binary optics is a new technology that makes use of the principle of diffraction instead of reflection or refraction to change an incident wavefront. This technology takes advantage of the recent progress in microlithography. There are many new and exciting applications for binary optics, and we can also expect to see the replacement of some conventional optical elements with binary optics.; In many ways a binary optic behaves like a diffraction grating with a period that changes continually over the surface of the optic. We find that energy is scattered into different diffraction orders, and there is scattering similar to "grass", "ghosts", "errors of run", "accidental errors of amplitude", and diffuse scattering from surface roughness, just like there is from a diffraction grating.; There are vector theories and scalar theories of diffraction. In this dissertation we give the conditions under which the various theories are applicable. We derive a formula for scattering from binary optics with slightly rough surfaces. By comparing this theory to computer simulations of scattering from binary optics we show that the theory can account for random fabrication errors. Formulas are also derived to predict the scattering from systematic errors. The author designed and built an instrument to measure scattering at small angles, and we show that measured scattering from binary optics can be predicted by the theories developed.