OPTICAL AND INFRARED PROPERTIES OF NANOMATERIALS FOR NIGHT VISION AND SURVEILLANCE SYSTEMS

— Nanomaterials are fundamentally transforming the capabilities of optical and infrared (IR) imaging technologies, offering unprecedented advancements for military night vision and surveillance systems. Their quantum-scale characteristics—marked by tunable bandgaps, enhanced surface-to-volume ratios, and tailored electronic interactions—enable fine control over photon absorption, emission spectra, and carrier dynamics across the entire infrared range. Among the most promising candidates in this domain are quantum dots (QDs), rareearth doped nanocrystals, and black phosphorus (BP), each possessing unique optoelectronic signatures that facilitate high-performance imaging under extreme and low-visibility conditions. Quantum dots, with size- and composition-dependent energy levels, can be precisely engineered to operate across short-wave infrared (SWIR), mid-wave infrared (MWIR), and long-wave infrared (LWIR) bands. Their compatibility with CMOS architectures and solution-processability makes them ideal for lightweight, scalable, and multi-spectral imaging arrays in unmanned aerial vehicles (UAVs) and portable surveillance platforms. Rare-earth doped nanocrystals, leveraging stable intra-4f transitions of lanthanide ions, offer narrowband and persistent IR emission. Their luminescence properties and thermal and chemical robustness make them indispensable in passive night vision, covert signaling, and long-duration reconnaissance under harsh battlefield environments. Black phosphorus, a 2D layered semiconductor with a thickness-tunable direct bandgap and intrinsic anisotropic conductivity, exhibits strong potential in MWIR photodetection and polarization-sensitive imaging. Recent improvements in surface passivation have significantly enhanced its environmental stability, paving the way for its integration into flexible and miniaturized IR sensors. This paper explores the structure-property relationships, infrared performance, and system-level integration strategies of these nanomaterials, emphasizing their transformative role in advancing next-generation military imaging solutions for superior tactical awareness and threat detection.