Hayward Tina M, Qadri Syed N, Santiago Freddie, Cheung C C, Christophersen Marc, Brimhall Nicole, Menon Rajesh
Opt Lett. 2024 Sep 15;49(18):5015-5018. doi: 10.1364/OL.531096.
We utilize inverse design and grayscale optical lithography to create a flat lens with a diameter and focal length of 50 mm, operating in the mid-wavelength infrared (MWIR) band. This lens demonstrates an extended depth of focus (DOF ≥±100m), a field of view (FOV ≥20°), and an angular resolution of 300rad. We characterize the lens's performance and use it as the primary optic in a hybrid refractive-diffractive telescope, which increases the angular resolution to 160rad. Using this telescope, we perform video imaging of aircraft and vehicles. Our experiments were constrained by the higher f-number of the focal plane array. Nonetheless, through rigorous simulations, we demonstrate that the inverse-designed flat lens surpasses the performance of a conventional Fresnel zone plate (FZP) in DOF and in FOV, even under these limitations. The flat lens, weighing approximately 20g, is significantly lighter than its refractive counterparts, confirming the feasibility of high-resolution, lightweight MWIR imaging systems.
我们利用逆向设计和灰度光学光刻技术，制作了一个直径和焦距均为50毫米的平面透镜，其工作在中波红外（MWIR）波段。该透镜具有扩展焦深（DOF≥±100米）、视场（FOV≥20°）以及300弧度的角分辨率。我们对该透镜的性能进行了表征，并将其用作混合折射-衍射望远镜的主光学元件，这将角分辨率提高到了160弧度。使用这台望远镜，我们对飞机和车辆进行了视频成像。我们的实验受到焦平面阵列较高f数的限制。尽管如此，通过严格的模拟，我们证明，即使在这些限制条件下，逆向设计的平面透镜在焦深和视场方面也优于传统的菲涅耳波带片（FZP）。该平面透镜重量约为20克，明显轻于其折射式同类产品，证实了高分辨率、轻量化MWIR成像系统的可行性。
