Design and fabrication of a diamond-turned hybrid diffractive/refractive singlet for visible applications at ORNL

摘要

Hybrid diffractive/refractive optics can be fabricated using traditional lithographic methods involving masks or holographic techniques as well as direct-write approaches that include electron-beam lithography, single-point diamond turning, and laser beam lithography. Only the direct-write methods have proven to be practical in producing continuous-form diffractive surfaces, or kinoforms, and among these methods, only diamond turning can easily produce large kinoforms on curved base surfaces. In this paper, we describe design and fabrication issues for a hybrid singlet produced by single-point diamond turning that functions in the visible portion of the spectrum and takes advantage of all of the degrees of freedom available from diamond turning: aspheric front surface to control spherical aberration, curved rear surface for elimination of coma, and kinoform surface placed on either curved base surface for control of primary chromatic aberration.