Metasurfaces offer design freedom and compact morphology for next-generation integrated photonics. Yet the optical performance of planar architectures is bounded by the structural degrees of freedom within the single lithographic layer. Three-dimensional (3D) height modulation offers a pathway for independent phase and spectral manipulation, but its realization is impeded by fabrication efficiency, precision, and process incompatibility with standard lithography. In this work, we report a wafer-scale topography-decoupled manufacturing technique. By integrating chemical mechanical polishing (CMP) into a multi-cycle overlay process, the construction of vertical profiles is resolved into a superposition of planarized two-dimensional (2D) patterning steps. The efficacy of this platform is validated on a 4-inch fused silica wafer, achieving precise height control with a standard deviation of 2.2 nm. A combinatorial library containing 46,072 silicon nanopillar metasurface units is constructed, demonstrating an expanded sRGB gamut coverage of 78.20%, representing a 20.7% enhancement over planar architecture.

Augmented reality eyewear offers a transformative interface poised to reshape human information interaction. In this context, silicon carbide (SiC) offers unique advantages for diffractive waveguides with its high refractive index and excellent thermal conductivity. However, in single-layer full-color displays, existing SiC waveguides generally remain thicker than 0.5 mm to reduce the bounce count of total internal reflection, thereby avoiding severe spatial variations in luminance and color. Here, we demonstrate a 0.35 mm SiC diffractive waveguide with an ultra-lightweight of only 1.98 g. The challenge of spatial non-uniformity is addressed by dual-parameter apodized gratings with continuously varying depth and duty cycle, enabling fine spatial control over local diffraction efficiency. To realize high-throughput production, a parallel gradient transfer method compatible with nanoimprint lithography is introduced, enabling wafer-scale patterning of four lens pairs per 8-inch SiC wafer. Furthermore, magnesium fluoride planarization suppresses grating visibility and achieves a high see-through transmittance of 92

The speed, dimensions, and immersive quality of communication have been continuously transformed by advances in information technology: from letters to telegraphs, telephones to video calls, and on-screen display to augmented reality (AR) displays. However, as demands for functional integration and high display quality intensify, significant limitations are encountered by conventional high-refractive-index glass-based diffractive waveguides, including bulkiness, weight, and rainbow artifacts in full-color displays. To overcome these challenges, we developed ultra-thin and ultra-light diffractive waveguides using 4H silicon carbide (SiC). These monolithic SiC waveguides are mass-produced via a specialized nanoimprinting (NIL) process on SiC wafers, leveraging the material’s high refractive index, thermal conductivity, and hardness. The resulting single-layer SiC waveguide achieves rainbow-artifact-free full-color displays while weighing just 3.795 g and measuring only 0.75 mm thick. Furthermore, we demonstrate compatibility with mass-produced prescription Fresnel lenses, addressing critical needs for myopia correction. This work advances diffractive waveguide display technology and offers a promising path for the future of information interaction.

We introduce a monolithic 4H-SiC metalens that achieves diffraction-limited focusing in high-power laser applications, with only a 5.9% temperature rise, a 6.6% focal drift, and an 11.4% cutting depth change after one hour of 15W, 1030 nm pulsed laser irradiation compared to a conventional lens. © 2022 The Author(s)

Effective heat dissipation is crucial for wearable devices, especially with the increasing popularity of augmented reality (AR) and virtual reality (VR) systems, which are typically in direct contact with human skin. However, cooling such devices remains a significant challenge due to their compact size and limited battery life. Here, we demonstrate a transparent radiative cooler with high thermal conductivity as an optical lens of smart glasses to achieve efficient thermal management. By integrating silicon carbide, used for enhanced thermal conduction, with an SiO2/TiO2/ITO multilayer structure, engineered for visible-light antireflection and radiative cooling, the surface temperature of the miniature projector, a major heat-generating component in smart glasses, is reduced from 54.3 degrees C above ambient to 29.1 degrees C under air convection. Notably, such a proposed cooler provides significant heat dissipation by simply depositing a micron-thick film without any external components, making it a promising solution for thermal management in modern electronic devices.

Respiratory rate monitoring has received widespread attention in medical field. Complex, expensive, and bulky commercial equipment limits the monitoring cost. To take full advantage of lab-on fiber technologies, we present a novel, compact size lab-on fiber breathing monitoring sensor based on a tapered no-core fiber (NCF) structure. The sensor is composed of humidity-sensitive polymer materials, single mode fiber (SMF)-NCF-SMF structure and monitors human respiratory rate by measuring exhaled humidity. The theoretical results prove that the self-imaging phenomenon can be induced by the changing of NCF diameter. The static relative humidity test results show a maximum relative humidity sensitivity of 0.0438 nm/%RH in the range of 35-58 %RH. Through the single-wavelength intensity fluctuation experiment, human respiratory information is collected. In the breathing process, a response time of 0.67 s can be achieved. The respiratory rate monitoring under different heart rates, breathing patterns, and human postures displays real-time tracking and high repeatability. Moreover, the compact size, low cost, and high sensitivity make our lab-on fiber sensor more competitive in the field of medical treatment and our daily life.

As information interaction technology advances, the efficiency, dimensionality, and user experience of information transmission have significantly improved. Communication has evolved from letters to telegraphs, markedly increasing transmission speed; from telephones to video calls, enhancing communication dimensions; and from smartphones to augmented reality (AR) displays, which provide increasingly immersive user experiences. Surface relief grating (SRG) diffractive waveguides have attracted considerable attention for their optimal balance between weight, size, optical performance, and mass production capabilities, positioning them as a leading solution for AR displays. However, as consumer expectations for higher display quality and better device integration rise, traditional high-refractive-index glass-based diffractive waveguides face limitations, including bulkiness, heavy weight, and conspicuous rainbow artifacts in full-color displays. To overcome these challenges, a novel solution: ultra-thin, lightweight silicon carbide (SiC) AR prescription glasses was proposed. This solution achieves full-color displays without rainbow artifacts, with total weight of just 2.685 g and thickness of only 0.55 mm. Moreover, these glasses are compatible with prescription Fresnel lenses and are well-suited for scalable mass production. This innovation provides a robust platform for the seamless integration of augmented reality into daily life, offering significant potential to enhance user interaction.

Enhancing energy density and efficiency in laser processing hinges on precise beam focusing, yet this often causes severe heat absorption and focus shifts in optical lenses. Traditional cooling methods increase cost and complexity, severely limiting versatility. Here, monolithic silicon carbide (SiC) metalens is introduced, which shows unparalleled thermal stability, integrated with a high-power laser. This metalens achieves diffraction-limited focusing with a numerical aperture (NA) of 0.5 and a focal length of 1 cm. Under a 1030 nm pulsed laser at 15 W for 1 h, it shows a minimal temperature rise of 3.2 °C and a tiny focal shift of 14 µm (0.1% relative), only 6% of the shift in conventional lenses. When used to cut a 4H-SiC substrate with the same laser, the metalens exhibit only an 11.4% change in cutting depth after 1 h of operation, correlating with the focal shift results. The results unveil a groundbreaking class of compact SiC photonics devices nearly impervious to heat absorption, representing a monumental leap for high-power laser systems and opening new horizons for their applications and efficiency.

Tailoring the absorption/emission through nanostructures from broadband to narrowband has attracted increasing attention due to the merits of high efficiency and compactness. However, most of the reported narrowband emitters require either complex fabrication process or thick coating of the suitable materials (~mm). In this paper, by exciting Berreman mode through a combination of Au mirrors and ultra‐thin layers of low‐loss uniaxial/biaxial anisotropic 2D van der Waals polar crystal hBN/α‐MoO3, a narrowband absorption/emission peak is realized in the mid‐infrared region. The measured quality‐factor of Berreman mode for hBN/Au and α‐MoO3/Au structure can reach up to 134 and 164, respectively. The deep subwavelength thickness (~nm) and bilayer architecture simplify the fabrication process. Furthermore, taking advantage of the in‐plane birefringence originating from α‐MoO3, the polarization of the absorbed/emitted radiation can be controlled through this planar configuration. Such ultrathin narrowband absorbers/emitters provide new opportunities for the advancements in thermal sources, infrared sensors, and thermophotovoltaic power generation systems.

Personal thermal management, especially heating up the space around human body, consumes substantial global resources. While traditional methods (such as room heaters) for personal heating are mostly energy-wasting and eco-unfriendly, ultra-thin textile with localized heating ability has recently gained significant attention. To date, passive radiative heating textiles are designed exclusively for indoor scenario and the coloration remains challenging. Herein, the authors report a colored nanophotonic structure textile (similar to 16 mu m thickness) with localized heating ability for both indoor and outdoor environments: (a) solar heating by selectively absorbing sunlight and converting it into heat (maximum absorbance similar to 50%) and (b) passive heating by suppressing radiative heat loss with a low-emissivity outer surface (infrared emissivity similar to 10%). This textile enables a 3.8 degrees C temperature enhancement of the artificial skin in indoor environment and a 6.3 degrees C temperature enhancement under sunlight compared with 2-mm-thick black sweatshirt, as well as excellent aesthetics, wearability and manufacturability. This colored textile with simultaneous solar and passive heating abilities is effective for energy-saving personal thermal management, and paves an innovative way to the sustainable development.

Simultaneous single-peak and narrowband thermal emitters with the merits of a simple configuration and ease-of-fabrication provide a path to enhance the energy utilization efficiency while they remain a challenge. Here, we demonstrate simultaneous single-peak and narrowband thermal emission by hybridizing metal microstructures with polar dielectric substrates. The metal provides single-peak emission in a broad spectrum range and the polar dielectric assists narrowband operation. The measured peak emissivity of the single-peak transverse-magnetic-polarized emission is 0.94 with a quality factor of 19 at the wavelength of 11.2 μm, and the emission at all other wavelengths from 2.5 μm to 25 μm is significantly suppressed. The utilization of the refractory material (molybdenum) provides further possibility for such a device to operate at temperatures up to 600 °C. These simultaneous single-peak and narrowband thermal emitters suggest avenues for numerous energy-efficient applications including gas sensing, thermal sources, and thermophotovoltaics.

A narrowband thermal emitter exhibits higher energy efficiency and sensitivity in molecule sensing and other mid-infrared (MIR) spectral range applications compared to a blackbody emitter. Most narrowband thermal emitters involving surface plasmons have a relatively low quality factor (Q-factor) and require complex fabrication processes. Here we propose a bilayer cavity-enhanced Tamm plasmon (TP) structure with a high/low refractive index bilayer sandwiched between a metal and distributed Bragg reflector (DBR) to achieve an enhanced Q-factor and maintain higher emittance over a conventional pure DBR-metal TP structure-based emitters. The large optical thickness of the high/low index bilayer cavity aids in increasing the Q-factor (∼172 for emission) of the cavity resonance. Furthermore, a tunable Q-factor is achieved (Q from 172 to 47 for emission) by incorporating phase-changing material Ge2Sb2Te5. This easy-to-fabricate and tunable high Q-factor emitter is competent as a narrowband MIR light source in molecule sensing, typically gas sensing applications.

An adaptive thermal camouflage device incorporating phase-changing material Ge2Sb2Te5 (GST) is experimentally demonstrated. Near-perfect thermal camouflage can be achieved continuously for the background temperature ranging from 30 degrees C to 50 degrees C.

Circularly polarized light (CPL) is utilized in various fields, including optical communication and biological imaging. To overcome the lack of circular-polarization-sensitive absorbers working at high temperature, a refractory and circular-polarization-sensitive absorber comprised of molybdenum zigzag arrays is proposed. At certain resonant wavelengths, one component of circular polarization is absorbed by confining electromagnetic field in the dielectric layer, while the other component is backscattered. The circular-polarization-sensitive absorber could be applied as a CPL thermal radiator as well as a reflective linear-to-circular polarizer. As a CPL thermal radiator, left-handed circular radiation and right-handed circular radiation are dominant at different temperatures, respectively. As a linear-to-circular polarizer, both perfect left-handed circularly polarized light and nearly perfect right-handed circularly polarized light are obtained.

The ability to control the polarization of thermal emissions is important for fundamental science and many applications such as multichannel infrared emitters and chemical sensing. Most previous works on controlling the polarization of thermal emission arc based on changing geometric sizes of the structures. The active control remains elusive so far. Here, we propose a design to actively switch the polarization of thermal emission. A metal-insulator-metal plasmonic thermal emitter with phase changing material Ge2Sb2Te5 (GST) as the insulator is experimentally demonstrated. The thermal emitter with top GST and gold ellipses can excite third-order magnetic resonances with perpendicular polarization along both short radius and long radius. The polarization of the thermal emission can be rotated by 90 degrees at 9.55 mu m peak wavelength when GST phase changes from the amorphous phase to the 40% crystalline phase. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Two wavelength-tunable thermal sources with sustained high emissivities are demonstrated with nano-scale films and phase changing materials.

Thermal emission control has been attracting increased attention in both fundamental science and many applications including infrared sensing, radiative cooling and thermophotovoltaics. In this paper, a tunable dual-band thermal emitter including phase-changing material Ge2Sb2Te5 (GST) is experimentally demonstrated. Two emission peak wavelengths are at 7.36 μm and 5.40 μm at amorphous phase, and can be continuously tuned to 10.01 μm and 7.56 μm while GST is tuned to crystalline phase. Compared with other dual-band metamaterial emitters, this tunable dual-band thermal emitter is only composed of an array of single-sized GST nanodisks (on a gold film), which can greatly simplify the design and manufacturing process, and pave the way towards dynamical thermal emission control.

Polar crystals can enable strong light-matter interaction at an infrared regime and provide many practical applications including thermal emission. However, the dynamic control of thermal emission based on polar crystals remains elusive as the lattice vibrations are solely determined by the crystal structure. Here, a nonvolatile tunable midinfrared thermal emitter enabled by a phase-changing film Ge2Sb2Te5 on silicon carbide polar crystal is demonstrated. By controlling the state of Ge2Sb2Te5 from an amorphous to a crystalline state, the emissivity of the thermal emitter is tuned from a low value to near unity with a maximum change in peak emissivity exceeding 10 dB over the Reststrahlen band of SiC (11.4 μm to 12.3 μm). This nonvolatile tunable thermal emitter, which presents a lot of advantages in terms of tunability, zero static power, angular insensitivity, and ease of fabrication, can be potentially applied for light sources, infrared camouflage, and radiative cooling devices.

Camouflage technology has attracted growing interest for many thermal applications. Previous experimental demonstrations of thermal camouflage technology have not adequately explored the ability to continuously camouflage objects either at varying background temperatures or for wide observation angles. In this study, a thermal camouflage device incorporating the phase-changing material Ge 2 Sb 2 Te 5 (GST) is experimentally demonstrated. It has been shown that near-perfect thermal camouflage can be continuously achieved for background temperatures ranging from 30 °C to 50 °C by tuning the emissivity of the device, which is attained by controlling the GST phase change. The thermal camouflage is robust when the observation angle is changed from 0° to 60°. This demonstration paves the way toward dynamic thermal emission control both within the scientific field and for practical applications in thermal information.

Dynamic thermal emission control has attracted growing interest in a broad range of fields, including radiative cooling, thermophotovoltaics and adaptive camouflage. Previous demonstrations of dynamic thermal emission control present disadvantages of either large thickness or requiring sustained electrical or thermal excitations. In this paper, an ultrathin (∼0.023λ, λ is the emission peak wavelength) metal‐insulator‐metal plasmonic metamaterial‐based zero‐static‐power mid‐infrared thermal emitter incorporating phase‐changing material GST is experimentally demonstrated to dynamically control the thermal emission. The electromagnetic modes can be continuously tuned through the intermediate phases determined by controlling the temperature. A typical resonance mode, which involves the coupling between the high‐order magnetic resonance and anti‐reflection resonance, shifts from 6.51 to 9.33 μm while GST is tuned from amorphous to crystalline phase. This demonstration will pave the way towards the dynamical thermal emission control in both the fundamental science field and a number of energy‐harvesting applications.