Imaging with an inverse-designed 50 mm-diameter f/1 MWIR flat lens with enhanced field of view and depth of focus.

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 ≥±100µm), a field of view (FOV ≥20°), and an angular resolution of 300µrad. 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 160µrad. 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.

Multilevel diffractive lens in the MWIR with extended depth-of-focus and wide field-of-view.

Optics in the mid-wave-infra-red (MWIR) band are generally heavy, thick and expensive. Here, we demonstrate multi-level diffractive lenses; one designed using inverse design and another using the conventional propagation phase (the Fresnel zone plate or FZP) with diameter = 25 mm and focal length = 25 mm operating at λ=4µm. We fabricated the lenses by optical lithography and compared their performance. We show that the inverse-designed MDL achieves larger depth-of-focus and better off-axis performance when compared to the FZP at the expense of larger spot size and reduced focusing efficiency. Both lenses are flat with thickness ≤0.5 mm and weigh ≤3.63 g, which are far smaller than their conventional refractive counterparts.

Nanoplasmonic pillars engineered for single exosome detection.

Exosomes are secreted nanovesicles which incorporate proteins and nucleic acids, thereby enabling multifunctional pathways for intercellular communication. There is an increasing appreciation of the critical role they play in fundamental processes such as development, wound healing and disease progression, yet because of their heterogeneous molecular content and low concentrations in vivo, their detection and characterization remains a challenge. In this work we combine nano- and microfabrication techniques for the creation of nanosensing arrays tailored toward single exosome detection. Elliptically-shaped nanoplasmonic sensors are fabricated to accommodate at most one exosome and individually imaged in real time, enabling the label-free recording of digital responses in a highly multiplexed geometry. This approach results in a three orders of magnitude sensitivity improvement over previously reported real-time, multiplexed platforms. Each nanosensor is elevated atop a quartz nanopillar, minimizing unwanted nonspecific substrate binding contributions. The approach is validated with the detection of exosomes secreted by MCF7 breast adenocarcinoma cells. We demonstrate the increasingly digital and stochastic nature of the response as the number of subsampled nanosensors is reduced from four hundred to one.

Recent patents on electrophoretic displays and materials.

Electrophoretic displays (EPDs) have made their way into consumer products. EPDs enable displays that offer the look and form of a printed page, often called "electronic paper". We will review recent apparatus and method patents for EPD devices and their fabrication. A brief introduction into the basic display operation and history of EPDs is given, while pointing out the technological challenges and difficulties for inventors. Recently, the majority of scientific publications and patenting activity has been directed to micro-segmented EPDs. These devices exhibit high optical reflectance and contrast, wide viewing angle, and high image resolution. Micro-segmented EPDs can also be integrated with flexible transistors technologies into flexible displays. Typical particles size ranges from 200 nm to 2 micrometer. Currently one very active area of patenting is the development of full-color EPDs. We summarize the recent patenting activity for EPDs and provide comments on perceiving factors driving intellectual property protection for EPD technologies.