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arXiv · 2004.13476

Inverse-designed flat lens for imaging in the visible & near-infrared with diameter > 3mm and NA=0.3

Monjurul Meem·Sourangsu Banerji·Apratim Majumder·Christian Pies·Timo Oberbiermann·Berardi Sensale-Rodriguez·Rajesh Menon
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Abstract

It is generally thought that correcting chromatic aberrations in imaging requires multiple surfaces. Here, we show that by allowing the phase in the image plane of a flat lens to be a free parameter, it is possible to correct chromatic aberrations over a large continuous bandwidth with a single diffractive surface. We experimentally demonstrate imaging using a single flat lens of diameter > 3mm, focal length = 5mm (NA = 0.3, f/1.59) that is achromatic from 0.45um to 1um. This combination of size, NA and operating bandwidth has not been demonstrated in a flat lens before. We experimentally characterized the point-spread functions, off-axis aberrations and the broadband imaging performance. In contrast to conventional lens design, we utilize inverse design, where phase in the focal plane is treated as a free parameter. This approach attains a phase-only (lossless) pupil function, which can be implemented as a multi-level diffractive flat lens that achieves achromatic focusing and imaging.

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Monjurul Meem, Sourangsu Banerji, Apratim Majumder, Christian Pies, Timo Oberbiermann, Berardi Sensale-Rodriguez, Rajesh Menon. 2020-04-25. Inverse-designed flat lens for imaging in the visible & near-infrared with diameter > 3mm and NA=0.3. https://doi.org/10.1063/5.0012759

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