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Photothermal applications, such as therapy, imaging, and catalysis, necessitate heat sources capable of generating high temperatures under mid‐infrared (mid‐IR) illumination. However, commonly used metal nanostructures suffer from low efficiency due to their high carrier concentrations, resulting in shallow surface heating and optical range restrictions. To overcome these limitations, this work proposes a novel approach employing materials that support phonon polaritons (PhPs) as a promising paradigm for light‐controllable heat sources. The theoretical demonstration reveals that hexagonal boron nitride (hBN) nanorods can produce up to 46 times more heat compared to plasmonic gold counterparts under resonant monochromatic light. This superior heating capability stems from the unique properties of PhPs, which enable stronger field confinement and deeper penetration within the nanostructure, leading to higher efficiency by circumventing the electrostatic shielding effect associated with plasmonic heating. Furthermore, this work demonstrates that the heating performance of hBN antennas can be optimized by manipulating their size, geometry, and material loss. Notably, the use of isotopically pure hBN can triple the heat power. These findings highlight the tremendous potential of hBN antennas as light‐controllable heat sources, opening up new possibilities for IR photothermal applications by harnessing materials that support PhPs. [ABSTRACT FROM AUTHOR]

The development of electronics and photonics is entering a new era of ultrahigh speed sensing, data processing, and telecommunication. The carrier frequencies of the next‐generation electronic devices inevitably extend beyond radio frequencies, marching toward the nominally photonics‐dominated territories, e.g., terahertz and beyond. As a result, electronic and photonic techniques naturally merge and seek common ground. At the forefront of this technical trend is the field of polaritonics, where polaritons are half‐light, half‐matter quasiparticles that carry the properties of both "bare" photons and "bare" dipole‐carrying excitations. The Janus‐faced nature of polaritons renders the unique capability of operando control using photoexcitation or applied electric field. Here, state‐of‐the‐art ultrafast polaritonic phenomena probed by scattering‐type scanning near‐field optical microscope (s‐SNOM) techniques is reviewed. The ultrafast dynamical control and loss‐reduction of the polariton propagation are discussed with special emphasis on the creation and probing of the tip or edge induced plasmon– and phonon–polaritons in low‐dimensional systems. The detailed technical aspects of s‐SNOM and its possible future development are also presented. [ABSTRACT FROM AUTHOR]

Infrared (IR) phototransistors are important building blocks for the true integration of flat‐panel optoelectronic detectors. Although significant progress is made in obtaining an InGaZnO active layer with IR response, the utilization of a high‐performance detector still has many challenges due to low efficiency, high power consumption, and lagging detection speed. Herein, a positive‐intrinsic‐negative (PIN) heterostructure phototransistor directly modulating the charges' transfer barrier with low power consumption (1 nW), high efficiency (EQE > 700%), a 200 Hz detecting bandwidth, and high detectivity (1 × 1011 cm Hz1/2 W−1) at an IR wavelength (1.5 µm in the high‐frequency circumstance) is demonstrated. These excellent sensing properties of the PIN phototransistor, together with its advantages of low power consumption and versatility, make the use of a heterostructure a powerful strategy for the development of on‐chip optoelectronic detectors. [ABSTRACT FROM AUTHOR]

Abstract: The Nicobar pigeon (Caloenas Nicobarica) belongs to the extinct dodo‐bird family and has been declared as an endangered species. Here, microscopic and spectroscopic measurements are carried out on the bird's feathers to study the structural coloration originating from the barbule nanostructures. A range of color shades is recorded with changing viewing and illumination angles at different locations of the feathers. A spectacular variation in colors is generated by photonic structures; red, green, and blue and their blends are observed. Hydrophobicity of the optical material is also investigated. A contact angle of ≈156° is observed demonstrating it to be superhydrophobic. Experimental observations of the optical properties are analyzed on these feathers for sensing made possible due to the material and structural properties at the interface between barbule's surface and solution. An optical response is observed with a redshift in optical spectra with increasing refractive index of the solution, which is correlated with concentration values. The structural coloration in Nicobar pigeon can be adopted for many practical applications such as color selective filters, nonreflecting coatings, and refractive index‐based sensing. [ABSTRACT FROM AUTHOR]

Organometal halide perovskites have been considered as promising candidates for high‐performance low‐cost photodetectors. Nonetheless, as perovskite photodetectors are usually built on glass or polymer substrates, their UV‐C (200–280 nm) photodetection ability is quite limited due to the high absorption of glass or polymer substrates. Here, a uniform UV photodetector array which integrates perovskite photodiodes with inorganic CsPbBr3 quantum dot (QD) fluorophor is reported. CsPbBr3 quantum dot fluorophor not only acts as an efficient down‐conversion layer to convert UV light into 510 nm light, but also functions as a protective layer to prevent degradation of hybrid organic–inorganic perovskite by UV light. Compared to direct UV‐C (279 nm) detection with perovskite photodiode, the QD integrated photodetector shows a higher responsibility and detectivity to UV‐C, with values enhanced by 1 order in magnitude. This work provides a low‐cost and effective approach for all perovskite‐based UV‐C photodetectors and imagers. [ABSTRACT FROM AUTHOR]

Optical encryption with multichannel, high complexity, and artistry characteristics has become one of the most significant approaches for modern information security. Recently emerged metasurface‐based optics consisting of planar subwavelength metamaterials has been engineered as an ideal platform for optical encryption because of its capability of manipulating various optical parameters and enhancing information storage capacity. However, limited encrypted channels and insufficient real‐time encryption abilities hinder its practical applications. A novel integrated metasurface is proposed, which can regulate the amplitude, phase, and polarization of light wave simultaneously to realize the combination of microprint and helicity‐multiplexed meta‐holography with negligible crosstalk. By encoding an online editable quick response code into the microprint as a keystore, an optical encryption device is demonstrated with 26‐1 storage capacity endowed by wavelength‐ and helicity‐dependent hologram images that can be employed in real time. The integration scheme enables multidimensional information storage and real‐time encryption and decryption capability, which provides an approachable way for the practical application of metasurface devices in the field of optical encryption. [ABSTRACT FROM AUTHOR]