Large-area, high-numerical-aperture multi-level diffractive lens via inverse design
Monjurul Meem, Sourangsu Banerji, C. Pies, Timo Oberbiermann, Apratim Majumder, Berardi Sensale‐Rodriguez, Rajesh Menon
Abstract
Flat lenses enable thinner, lighter, and simpler imaging systems. However, large-area and high-NA flat lenses have been elusive due to computational and fabrication challenges. Here we applied inverse design to create a multi-level diffractive lens (MDL) with thickness <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mo><</mml:mo> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>1</mml:mn> </mml:mrow> <mml:mo>.</mml:mo> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>35</mml:mn> </mml:mrow> <mml:mspace width="thickmathspace"/> <mml:mtext>µ</mml:mtext> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">m</mml:mi> </mml:mrow> </mml:math> , diameter of 4.13 mm, and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">N</mml:mi> <mml:mi mathvariant="normal">A</mml:mi> </mml:mrow> <mml:mo>=</mml:mo> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>0.9</mml:mn> </mml:mrow> </mml:math> at wavelength of 850 nm (bandwidth <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mo>∼</mml:mo> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>35</mml:mn> </mml:mrow> <mml:mspace width="thickmathspace"/> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">n</mml:mi> <mml:mi mathvariant="normal">m</mml:mi> </mml:mrow> </mml:math> ). Since the MDL is created in polymer, it can be cost-effectively replicated via imprint lithography.