Interdisciplinary Theory & Technology

The US Patent Office issued this patent with the title and abstract originally filed rather than the submitted revised title and abstract. The appropriate title and abstract (which NRI believes more accurately describes the patent) is provided below.

An optical filtering system includes a graded-index optical element having a non-quadratic phase profile, and one controllable optical filtering element that is controlled according to calculations employing bases functions associated with the graded-index optical element. The invention expands upon quadratic-phase optics techniques for controllable filtering involving Fourier and fractional Fourier planes induced by individual lenses, lens systems, quadratic-phase graded index materials, and some forms of particle beam systems utilized in electron microscopy. The invention generalizes these controllable filtering processes and design methodologies to non-quadratic phase environments, while providing for the realization of non-positive-definite transfer functions from positive definite filter elements. Applications include integrated photonics, optical computing, and more general types of particle beam systems as may be used in electron microscopy and ion lithography.