“Versatile Diffractive Flat Optics”

Prof. Rajesh Menon,
Dir. Lab. for Optical Nanotechnologies
Univ. Utah, Salt Lake City

Traditional refractive lenses are bulky owing to their curvature. Flat diffractive lenses can overcome this difficulty, but traditional diffractive optics have limited reach, primarily due to chromaticity. Recently, we have shown that by treating the “imaging” phenomenon as simply information transfer from the object to the image plane, the spatial distribution of the phase in the focal plane can be an arbitrary function.

Using this concept, we have shown that allowing the phase in the image plane of a flat lens to be a free parameter enables imaging properties of unprecedented versatility in flat, multilevel diffractive lenses (MDLs).

Our research group has demonstrated binary multi-level diffraction lenses in three high performance categories: super-achromatic lenses in three wavelength regions (8-12um 0.45-1 um, 1.5-150 um), high NA of 0.9 of at 0.85um, and extreme depth of focus (5mm to 1200mm).

We believe that our inverse-designed flat MDLs, which can be manufactured using low-cost imprinting techniques, could prove widely applicable—especially where weight and restricted form factor are important considerations, as in aerospace and airborne imaging as well as augmented and virtual reality displays.