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Hyperspectral imaging technology can record the spatial and spectral information of the targets and significantly enhance the levels of military reconnaissance and target detection. It has scientific importance to mimic "homochromatic and homospectral" camouflage materials that have hyperspectral similarity with the green vegetation, one of the most common natural backgrounds. It is a big challenge to exquisitely simulate the spectral of green vegetation in visible and near‐infrared windows because of the slight differences between the artificial green dyes and vegetation, the instability of chlorophylls, and the easy loss of hydroxide bands due to the loss of water from the camouflage materials. Herein, a novel kind of biomimetic material of green vegetation was designed through the incorporation of chlorophylls into the crystal lattices of single‐crystalline anhydrous guanine microplates for the first time. The synthesized chlorophylls‐doped anhydrous guanine crystals exhibit high reflectance intensity and depolarization effect, thus can be applied as biomimetic camouflage materials that mimic green vegetation with high reflectivity and low polarization in the visible and near‐infrared regions. The factors influencing the formation of dye‐doped organic crystals under mild conditions were thoroughly investigated and the characterizations using electron microscopies and fluorescence confocal laser scanning microscopy clearly confirm the occlusion of chlorophylls into the crystal lattices of guanine crystals. The thermal stability experiments clearly indicate that the chlorophylls‐doped guanine crystals possess long‐term stability at high temperature. This study provides a new strategy for the synthesis of multifunctional materials comprised of organic crystals. [ABSTRACT FROM AUTHOR]

High emissivity coatings on hypersonic vehicle surfaces dissipate heat by emitting thermal radiation. While the difficulty of increasing emissivity limits the performance of coatings to improve heat-dissipation of the thermal insulation felt. Herein, a novel high-reflectivity and high-emissivity integrated double-layer coating was developed to enhance the thermal insulation performance of the alumina fiber fabric. The coating comprised of TiO 2 @SiO 2 (T@S) as reflective agent and ZrO 2 /SiC w (ZSC) as emittance agents, was applied on the surface of alumina fiber fabric (AFF). The reflecting effect of radiation heat from the high reflective agent enhanced the thermal insulation properties of the double-layer coating. In the wavelength range of 0.4–2.5 μm, the average emissivity of the ZSC coating was 0.83 and the average reflectivity of the T@S coating was 0.63. With continuous heating at 1400 °C for 10 min with a butane torch, the temperature on the backside of the T@S–ZSC-coated AFF remained relatively stable at 225 °C, which is notably decreased by 80 °C compared to that of the single-layer ZSC-coated AFF. The tensile strength of AFF with T@S–ZSC coating reached 35 MPa after being heat treated at 1200 °C. Moreover, the bonding strength between the coating and the AFF substrate was measured to be 0.15 MPa. The double-layer coating with high emissivity and reflectivity, along with a flexible AFF substrate, offers a promising solution for addressing the challenging of surface heat-dissipation in hypersonic vehicles. [ABSTRACT FROM AUTHOR]

This work involves the introduction of niobium oxide into lanthanum aluminate (LaAlO3) via a conventional solid-state reaction technique to yield LaAlO3:Nb (LaNbxAl1−xO3+δ) samples with Nb5+ doping levels ranging from 0.00 to 0.25 mol%. This study presents a comprehensive investigation of the effects of niobium doping on the phase evolution, defect control, and reflectance of LaNbxAl1−xO3+δ powder. Powder X-ray diffraction (XRD) analysis confirms the perovskite structure in all powders, and XRD and transmission electron microscopy (TEM) reveal successful doping of Nb5+ into LaNbxAl1−xO3+δ. The surface morphology was analyzed by scanning electron microscopy (SEM), and the results show that increasing the doping concentration of niobium leads to fewer microstructural defects. Oxygen vacancy defects in different compositions are analyzed at 300 K, and as the doping level increases, a clear trend of defect reduction is observed. Notably, LaNbxAl1−xO3+δ with 0.15 mol% Nb5+ exhibits excellent reflectance properties, with a maximum infrared reflectance of 99.7%. This study shows that LaNbxAl1−xO3+δ powder materials have wide application potential in the field of high reflectivity coating materials due to their extremely low microstructural defects and oxygen vacancy defects. [ABSTRACT FROM AUTHOR]

Substrate transfer technology is a common way to prepare high-power infrared light emitting diode (IRLED), which seriously affects the photoelectric performance and reliability of LED. In this paper, a preparation technology of LED with composite metal substrate is presented. Based on electroplating and electron beam evaporation, AuGeNi/Au(1)/Au(2)/Cu composite metal substrate with thickness of 70 nm/30 nm/100 nm/45 μm was prepared, and low resistivity of 4.65 × 10−6 Ω⋅cm2 and high reflectance of 91.3 % were obtained. Compared with the original GaAs substrate, the light output power (LOP) of electroluminescence is increased by 89.2 % at the current of 300 mA.

This work involves the introduction of niobium oxide into lanthanum aluminate (LaAlO3) via a conventional solid-state reaction technique to yield LaAlO3:Nb (LaNbxAl1−xO3+δ) samples with Nb5+ doping levels ranging from 0.00 to 0.25 mol%. This study presents a comprehensive investigation of the effects of niobium doping on the phase evolution, defect control, and reflectance of LaNbxAl1−xO3+δ powder. Powder X-ray diffraction (XRD) analysis confirms the perovskite structure in all powders, and XRD and transmission electron microscopy (TEM) reveal successful doping of Nb5+ into LaNbxAl1−xO3+δ. The surface morphology was analyzed by scanning electron microscopy (SEM), and the results show that increasing the doping concentration of niobium leads to fewer microstructural defects. Oxygen vacancy defects in different compositions are analyzed at 300 K, and as the doping level increases, a clear trend of defect reduction is observed. Notably, LaNbxAl1−xO3+δ with 0.15 mol% Nb5+ exhibits excellent reflectance properties, with a maximum infrared reflectance of 99.7%. This study shows that LaNbxAl1−xO3+δ powder materials have wide application potential in the field of high reflectivity coating materials due to their extremely low microstructural defects and oxygen vacancy defects.

The rapid development and wide application of laser technology, together with the gradually increased output energy of lasers, pose a great threat to safety. Therefore, the demand for anti-laser is urgent. Highly reflective coatings can dissipate large incident laser energy through reflection. In this paper, zirconium silicate (ZrSiO4) highly reflective ceramic glaze coatings were prepared on both ceramic and metal substrates. Their macro and micro structure evolution treated at different heating temperatures were studied. The reflectivity of the coatings was on average 85% over the range of 400 and 2400 nm and reaches a maximum of 94% at 1064 nm. The coatings on ceramic substrates showed good stability when irradiated under high-energy continuous laser with power density of 2000 W/cm2 for 60 s. On the other hand, the coatings prepared on metal substrates formed a layer of dense, glaze-like material after high-energy continuous laser irradiation with power density of 500 W/cm2 for 10 s or 1000 W/cm2 for 5 s, demonstrating good anti-laser performance.

Biomimetic synthesis of guanine crystals has been focused on in the last years. However, multi‐functional guanine crystals occluded with fluorescent molecules have not been realized in the laboratory. Here, the controllable synthesis of guanine crystal microplatelets with fluorescence and pearlescence was achieved for the first time by incorporating Nile red (NR) or fluorescein isothiocyanate (FITC) molecules into guanine crystals. The synthesized fluorescent guanine crystals are pure β‐phase anhydrous guanine single crystals. Aqueous suspensions with NR‐ and FITC‐doped guanine crystals exhibit distinct pearlescence. The fluorescence intensities of NR and FITC were greatly enhanced after being doped into guanine crystals due to the inhibition of aggregation‐caused quenching. Moreover, films composed of fluorescent guanine microplatelets exhibit high diffuse reflection intensity (70 %). This work provides a strategy to synthesize multifunctional materials composed of organic crystals occluded with dyes. [ABSTRACT FROM AUTHOR]

A new structure of film bulk acoustic resonator (FBAR) based on phononic crystal (PnC) was proposed.The phononic crystal was used as the acoustic reflection layer at the bottom of the bulk acoustic wave resonator, which has the characteristics of high reflectivity and low transmittance of elastic wave in its band gap.The band gap characteristics of four kinds of phononic crystals with different structures were calculated by the finite element software COMSOL Multiphysics.The main conclusions are as follows.If the bulk acoustic resonator is working within the band gap of the phononic crystal, PnC can be used as the bottom acoustic reflection layer of the FBAR.With using PnC as the acoustic energy reflect structure, the impedance curve of FBAR is smooth, and the quality factor is closed to traditional FBAR with a value of 859 and effective mechanical coupling coefficient of 6.32%.

Lithium niobate is an excellent optoelectronic and nonlinear material, which plays an important role in integrated optics. However, lithium niobate is difficult to etch due to its very stable chemical nature, and the microstructure of lithium niobate's metasurface is generally of subwavelength, which further increases its processing difficulty. Here, by using Ar+-based inductively coupled plasma etching and KOH wet etching, we improve the etching quality and fabricate a Fano-resonant metasurface based on lithium niobate on insulator, which has a very high reflectivity of 92% at near-infrared wavelength and the potential of becoming a high-reflectivity film. In addition, to evaluate the practical performance of the metasurface, we constructed a Fabry–Perot cavity by using it as a cavity mirror, whose reflection spectrum shows a finesse of 38. Our work paves the way for the development of functional metasurfaces and other advanced photonic devices based on lithium niobate on insulator. [ABSTRACT FROM AUTHOR]

Radiative cooling is a passive cooling technology that radiates heat to outer space without any energy input thus such technology is of great significance for alleviating environmental pollution and consumption of energy. However, achieving cooling during the daytime normally requires a series of complex structural designs that are economically inefficient and unscalable fabrication process. In this work, inspired by the nanostructure of Pieris rapae butterfly wings, we fabricate a double-layered polymeric film with a bead-like structure which can scatters incident light intensely for passive radiative cooling. Through optical characterization, it was demonstrated that the film can provide a high solar reflectivity of ∼92.4 % and a high atmospheric window emissivity of ∼93.2 %. In field tests, the film can achieve a maximum temperature drop of 6.5 °C and an average temperature drop of 3.8 °C under direct sunlight, and theoretically producing an effective cooling power of 123.8 W m−2. The as-prepared film could be fabricated through a low-cost template process, and our work presents a new approach to the application of radiative cooling technology in the field of building cooling. [ABSTRACT FROM AUTHOR]

• A two-step Au deposition improved the reflectivity while retaining the low resistivity is demonstrated. • The AuGeNi/Au(1)/Au(2) (70 nm/30 nm/100 nm) Ohmic contact to N-AlGaAs with a low resistivity of 4.65 × 10−6 Ω·cm2 and a high reflectivity of 93.11 % at 850 nm have been obtained after RTP 420 °C for 1 min. • The LOP of IRLED with AuGeNi/Au(1)/Au(2)/Cu (70 nm/30 nm/100 nm/45 μm)composite metal substrate is 89.2 % higher than that of GaAs substrate at 300mA current. Substrate transfer technology is a common way to prepare high-power infrared light emitting diode (IRLED), which seriously affects the photoelectric performance and reliability of LED. In this paper, a preparation technology of LED with composite metal substrate is presented. Based on electroplating and electron beam evaporation, AuGeNi/Au(1)/Au(2)/Cu composite metal substrate with thickness of 70 nm/30 nm/100 nm/45 μm was prepared, and low resistivity of 4.65 × 10−6 Ω⋅cm2 and high reflectance of 91.3 % were obtained. Compared with the original GaAs substrate, the light output power (LOP) of electroluminescence is increased by 89.2 % at the current of 300 mA. [ABSTRACT FROM AUTHOR]

Passive daytime radiative cooling (PDRC) has attracted intensive attention due to its great potential in reduced energy consumption. However, the practical application for PDRC is greatly affected by geographical location and the intrinsic cooling power. Herein, a composite flexible fabric with the synergistic effect of evaporative cooling and radiative cooling is reported. A porous polymer coating with both a high solar reflectivity (90%) and a high infrared thermal emissivity (83%) is fabricated on the top side of the fabric, which can achieve effective PDRC performance. Meanwhile, hygroscopic salts are loaded on the bottom side of the fabric, which can capture water vapor at night and realize evaporative cooling during the daytime. The temperature reduction of 10.8 °C can be achieved under the direct sunlight irradiation (465 W m−2) for the prepared fabric in the outdoor experiment. The combination of radiative cooling and evaporative cooling breaks through the traditional single passive cooling mode and has great potential in further improving the performance of passive cooling. [ABSTRACT FROM AUTHOR]

Lithium niobate is an excellent optoelectronic and nonlinear material, which plays an important role in integrated optics. However, lithium niobate is difficult to etch due to its very stable chemical nature, and the microstructure of lithium niobate’s metasurface is generally of subwavelength, which further increases its processing difficulty. Here, by using Ar+-based inductively coupled plasma etching and KOH wet etching, we improve the etching quality and fabricate a Fano-resonant metasurface based on lithium niobate on insulator, which has a very high reflectivity of 92% at near-infrared wavelength and the potential of becoming a high-reflectivity film. In addition, to evaluate the practical performance of the metasurface, we constructed a Fabry–Perot cavity by using it as a cavity mirror, whose reflection spectrum shows a finesse of 38. Our work paves the way for the development of functional metasurfaces and other advanced photonic devices based on lithium niobate on insulator.

[Display omitted] • A high-performance HSEC coating is fabricated for large-scale building cooling. • The HSEC coating has high average solar reflectance (95.1%) and MIR-infrared emissivity (92.5%). • The HSEC coating realizes ambient cooling up to 4.2 °C during the daytime. • The HSEC coating shows excellent anti-contamination property and radiative stability. The building cooling has aroused widespread attention due to its significant contribution to both global warming and energy usage. To combat global warming and reduce energy consumption, an environmentally friendly beneficial alternative to electric cooling for buildings is passive daytime radiative cooling (PDRC). However, many of the reported radiative coolers still suffer from the challenge of complex preparation processes and high costs, making it difficult to scale up for building applications. Herein, the utilization of abundant and low-cost natural resources (i.e., cellulosic biomass and minerals) is strategized to produce radiative cooling material and incorporate this material into building cooling systems to boost global carbon neutrality. Guided by this concept, a hydrophobic SiO 2 /EC composite (HSEC) coating is designed by embedding nano-sized wollastonite-based SiO 2 particles into porous ethyl cellulose (EC) polymer, and subsequently through polydimethylsiloxane (PDMS) dispersion spray treatment. Benefiting from the sufficient scattering by the nano-SiO 2 particles and randomly dispersed light-scattering air voids, the resulting cooling coating shows a high solar reflectivity of 95.1 %. More importantly, the molecular vibration of the chemical in HSEC coating results in a high atmospheric window emissivity of 92.5 %. In the field test, the HSEC coating remained approximately 4.2 °C below the ambient temperature under intense solar irradiation of 412.5 W⋅m−2. This work not only offers a promising strategy for realizing the high-value utilization of wollastonite resources in building materials, but also provides a controllable approach for large-scale preparation of highly efficient radiative cooling materials to alleviate building cooling demands. [ABSTRACT FROM AUTHOR]

Reductions in energy consumption for high temperature processes are an important research topic, especially due to the ongoing energy crisis scenario. Based on the several possibilities of saving it, thermal coatings are an economical and technical viable possibility of tailoring the optical properties of a material surface. Although many studies have been published on the benefits of high emissivity and high reflectivity ceramic coatings, there is still a lack of a clear understanding on the correlation between thermal radiation heat transfer, solid state physics, and material science technology. This study aims to create a connection between these areas in order to provide basic guidelines for the correct use of thermal ceramic coatings, leading to achieving the maximum decrease in energy consumption by their use. [ABSTRACT FROM AUTHOR]

Cholesteric liquid crystals (CLCs) have been widely applied in optical filters due to Bragg reflection caused by their helical structure. However, the reflectivity of CLC filters is relatively low, commonly less than 50%, as the filters can only reflect light polarized circularly either left- or right-handedly. Therefore, a high-reflective CLC filter with a single-layer template was proposed which may reflect both right- and left-handed polarized light. The CLC filters of the red, green, blue color were fabricated by the templating technology, which show good wavelength consistency. Additionally, a multi-phase liquid crystal filter with high reflectance was demonstrated by the single-layer templating technology. The templated CLC or multi-phase liquid crystal filters show great potential applications in the optical community, reflective display, and lasing.

Film bulk acoustic resonator (FBAR)-based filters have attracted great attention because they can be used to build high-performance RF filters with low cost and small device size. Generally, FBARs employ the air cavity and Bragg mirror to confine the acoustic energy within the piezoelectric layer, so as to achieve high quality factors and low insertion loss. Here, two-dimensional (2D) phononic crystals (PhCs) are proposed to be the acoustic energy reflection layer for an FBAR (PhC-FBAR). Four kinds of PhC structures are investigated, and their bandgap diagrams and acoustic wave reflection coefficients are analyzed using the finite element method (FEM). Then, the PhCs are used as the acoustic wave reflectors at the bottom of the piezoelectric stack, with high reflectivity for elastic waves in the specific frequency range. The results show that the specific PhC possesses a wide bandgap, which enables the PhC-FBAR to work at a broad frequency range. Furthermore, the impedance spectra of PhC-FBARs are very smooth with few spurious modes, and the quality factors are close to those of traditional FBARs with air cavities, showing the application potential of the PhC-FBAR filters with wide bandwidth and high power capability.

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We have developed fast switching twisted‐vertically aligned mode reflective LCD using mortar‐shaped pixel structure. We realized axially symmetric pretilt angle in each pixel by the mortar‐shaped pixel structure fabricated by the UV pattern exposure and achieved high quality reflective LCD with high reflectivity and wide viewing angle range. [ABSTRACT FROM AUTHOR]

Cr/C multilayer optics are a suitable choice for the tender X‐ray range (1–4 keV) that covers the K absorption edges of P, S, Cl and 3d transition metals as well as the L absorption edges of 4d transition metals. In particular, these optics are studied in order to optimize the optical properties of collimated plane‐grating monochromators. In this paper, the structure, stress and optical properties of Cr/C multilayers (fabricated using direct‐current magnetron sputtering) with bi‐layer number of 20 and the same period (about 11.64 nm) but different Cr thickness ratio (0.20–0.80) are investigated. Firstly, the grazing‐incidence X‐ray reflectivity at 8.04 keV was measured. These measurements were fitted assuming a multilayer structure with a four‐layer and non‐periodic model. Results and fitting show that interface widths increase with the Cr thickness ratio. The results obtained from X‐ray diffraction at 8.04 keV were consistent with high‐resolution transmission electron microscopy which showed an increase in grain size of the Cr layers. In addition, the stresses of the Cr/C multilayers have been measured and the results show that the stress value approaches zero when the Cr thickness ratio is about 0.45. The reflectivity of a Cr/C multilayer with Cr thickness ratio of 0.37 was measured and reaches 26.6% at 1.04 keV. The measured reflectivity matches very well with the predicted value using the four‐layer and non‐periodic model, which confirmed the viability of the prediction. Thus, the reflectivity at 1.04 keV of a Cr/C multilayer with different Cr thickness ratio was predicted and was found to drastically decrease when the Cr thickness ratio is larger than 0.37. It has been determined that a Cr thickness ratio value of 0.37 is the best choice for a Cr/C multilayer in view of high reflectivity and low stress. [ABSTRACT FROM AUTHOR]

The high reflectivity design of the one-dimensional (1-D) heterostructure photonic crystal is investigated in infrared regions 3 to 5 and 8 to 12 µm. First, the reflection characteristics of the light waves in the 1-D periodic photonic crystal are systematically analyzed. Calculations using the transfer matrix method and simulations verify that the λ/4 dielectric film is the optimum option for achieving the ideal optical reflectivity in a certain wavelength range. The merging of the even-layered high-reflective photonic crystals can be used to expand the gap of the infrared band. In contrast, a combination of the odd-numbered composite photonic crystals can be used to achieve a high transmittance at a wavelength of 10.6 µm with a larger gap in the infrared region. Accordingly, an enhanced photonic crystal is designed using silver metal at the interface and even-numbered dielectric films of Ge and ZnS with 23 layers of the 1-D metal. The simulated reflectivity of this photonic crystal ranges from 95% to 99.9% in wavelength ranges 3 to 5 and 8 to 14 µm. This design significantly reduces the number of layers required for forming a 1-D high-reflective photonic crystal in the infrared bands 3 to 5 and 8 to 12 µm. [ABSTRACT FROM AUTHOR]

A kind of reflective mode LCD was reported years ago by professor Shin‐Tson Wu, called Mixed‐mode Twisted Nematic (MTX) LCD[1]. Based on MTN mode RLCD, we promoted the contrast ratio and reflectivity of RLCD by optimizing the cell structure and pixel design. Meanwhile, according to controlling the different optical layer axis directions and using new type materials, the contrast ratio and reflectivity are increased further. To improve the visibility of RLCD in a dark environment, we also developed the front light unit solution. [ABSTRACT FROM AUTHOR]

Line laser is widely used in structural light three-dimensional (3D) measurement of metal parts; however, the laser stripes are severely disturbed when measuring complex surfaces. In the process of laser plaSignal sent for page signal is not returning for this article, hence not possible to proceed. Please do the needful, also return the task only after solving the issue. ne calibration, the laser stripe will be damaged by the pattern on the calibration board; when measuring metal surfaces, the laser stripe will be exposed unevenly. Overexposed parts show highlights and artifacts, while underexposed stripes appear burrs, high noise, or even undetectable due to material absorption, which will greatly affect the accuracy of stripe center extraction. In this paper, a modified multi-exposure fusion (MMEF) method is proposed to improve the dynamic range of laser stripe images by enhancing underexposed regions and reducing saturation. The MMEF method uses a "smoothness" index and a "validity" index to give more weight to smooth, Gaussian-like laser stripe patterns and extract reliable modulation information. To evaluate the effectiveness of our method, the performance of the MMEF method is tested for laser plane calibration and metal surface reconstruction, and the high dynamic range (HDR) method, retrieval fusion (RF) method, and exposure fusion (EF) method are introduced for comparison. Measurement experimental results show that the MMEF method proposed in this paper improves the laser plane calibration accuracy by 86.0% and the 3D measurement accuracy of metal surface by 12.5%. • A modified fusion method is proposed for laser measuring complex specular surfaces or surfaces. • Issues of high light, artifacts and noise in laser measurement of complex surfaces are addressed. • Restoration of Gaussian laser stripes provides basis for subpixel centroid extraction. • Accuracy of laser calibration and 3D measurement of specular samples is enhanced and verified. [ABSTRACT FROM AUTHOR]

[Display omitted] • We explored the application of highly reflective glaze as anti-laser material firstly. • Clinker could generate dense glaze like structures during laser irradiation. • The precipitated crystals in the glaze have excellent reflectivity performance. The rapid development and wide application of laser technology, together with the gradually increased output energy of lasers, pose a great threat to safety. Therefore, the demand for anti-laser is urgent. Highly reflective coatings can dissipate large incident laser energy through reflection. In this paper, zirconium silicate (ZrSiO 4) highly reflective ceramic glaze coatings were prepared on both ceramic and metal substrates. Their macro and micro structure evolution treated at different heating temperatures were studied. The reflectivity of the coatings was on average 85% over the range of 400 and 2400 nm and reaches a maximum of 94% at 1064 nm. The coatings on ceramic substrates showed good stability when irradiated under high-energy continuous laser with power density of 2000 W/cm2 for 60 s. On the other hand, the coatings prepared on metal substrates formed a layer of dense, glaze-like material after high-energy continuous laser irradiation with power density of 500 W/cm2 for 10 s or 1000 W/cm2 for 5 s, demonstrating good anti-laser performance. [ABSTRACT FROM AUTHOR]

Metallic thin films have been evaluated as adhesive layers for first surface mirrors. Thin films (0.5–4 nm thick) of Cr, Cu, Ge, Sn, and Ni, capped with an over layer of 100 nm of Ag have been deposited by means of ion assisted electron beam evaporation onto glass substrates. The specular reflectance, conductivity, morphology, adhesion, and abrasion resistance of the mirrors have been assessed and compared. This work demonstrates the superior Ni and Ge adhesion and abrasion resistance to Ag thin films, while Cr and again Ni are the best candidates in terms of reflectance enhancement. In particular, 4 nm of Ni increases the Ag reflectance from 95.7% to 96.7%, exhibits the strongest adhesion as determined by the cross hatch tape test and the lowest loss of material after the different abrasion tests is just 50% in comparison to 100% for Ag‐coated glass substrates. [ABSTRACT FROM AUTHOR]

A high-reflectivity electromagnetic two-axis microscanner is presented, which uses dielectric multi-layer coating on the aluminum film at the reflective surface. The microscanner is driven biaxially with the torque generated between the radially directed magnetic field and the current path through a single-turn copper coil patterned on the scanner. To enhance reflectivity, dielectric multi-layers of Al 2 O 3 and TiO 2 films are coated on the aluminum reflective surface of the mirror. A reflectance of 96.31% was obtained by using two pairs of dielectric films at a wavelength of 850 nm. Laser irradiation tests were performed to measure the operational reliability of the microscanner. The temporal drift of the optical scan angle for the mirror with two pairs of dielectric layers was measured to be 0.16° during a 6-h operation using a femtosecond pulsed laser irradiation with an average power of 2.3 W and a high repetition rate of 80 MHz. However, for the mirror where the reflection surface was coated with an aluminum layer only, a 1.74° degradation of the tilting angle was observed. [ABSTRACT FROM AUTHOR]

We demonstrate mirror-finished superhydrophobic aluminum surfaces fabricated via the formation of anodic alumina nanofibers and subsequent modification with self-assembled monolayers (SAMs). High-density anodic alumina nanofibers were formed on the aluminum surface via anodizing in a pyrophosphoric acid solution. The alumina nanofibers became tangled and bundled by further anodizing at low temperature because of their own weight, and the aluminum surface was completely covered by the long falling nanofibers. The nanofiber-covered aluminum surface exhibited superhydrophilic behavior, with a contact angle measuring less than 10°. As the nanofiber-covered aluminum surface was modified with n-alkylphosphonic acid SAMs, the water contact angle drastically shifted to superhydrophobicity, measuring more than 150°. The contact angle increased with the applied voltage during pyrophosphoric acid anodizing, the anodizing time, and the number of carbon atoms contained in the SAM molecules modified on the alumina nanofibers. By optimizing the anodizing and SAM-modification conditions, superhydrophobic behavior could be achieved with only a brief pyrophosphoric acid anodizing period of 3 min and subsequent simple immersion in SAM solutions. The superhydrophobic aluminum surface exhibited a high reflectance, measuring approximately 99% across most of the visible spectrum, similar to that of an electropolished aluminum surface. Therefore, our mirror-finished superhydrophobic aluminum surface based on anodic alumina nanofibers and SAMs can be used as a reflective mirror in various optical applications such as concentrated solar power systems. [ABSTRACT FROM AUTHOR]

This paper reports the development of high volume fraction SiCP/Al composite-bismuthate glass multilayer films optics Au-mirror with high reflectivity in a wavelength range of 760 to 1000 nm. Multilayer films were fabricated using an radio frequency-magnetron sputtering deposition system. The measured reflectivity of Ta2O5/SiO2/Au/Cr metal plus dielectric films optics Au-mirror could reach up to ≥97%. Then, on the basis of experiments, a Φ75-mm high volume fraction SiCP/Al composite-bismuthate glass multilayer optical Aumirror for a wavelength range of 760 to 1000 nm was manufactured. The tested results indicate that a peak-tovalley value of 0.854λ (λ = 632.8 nm) was achieved on the Au-mirror surface, and the slope deviation error for the flat surface was lower than 0.153λ root mean square. The surface roughness of Ta2O5/SiO2/Au/Cr multilayer thin films was 1.30 nm (Ra). [ABSTRACT FROM AUTHOR]

A novel antimony doped tin oxide (ATO) and TiO 2 double-layers coated HGM was developed in this project. The ATO, which has excellent IR-insulation property, was coated on the HGM as the first layer and the TiO 2 , which has high reflectivity, was the outmost layer. Therefore, when the modified HGM is coated on the outside of the building walls, the incident light is firstly reflected by the TiO 2 layer then insulated by the ATO layer. Most of the radiative thermal transfer was blocked by this double-layers coating. The building envelope can be thus protected by the HGM for less heat gains. Compared with original HGMs, the reflectivity increased by 19.6% and the transmittance decreased by 85.7%. In addition, this coating barely changed the thermal conductivity, which only increased by about 8%. By this method, most of the thermal conduction and radiative thermal transfer are blocked. The energy consumption and carbon emission of a building can be reduced. [ABSTRACT FROM AUTHOR]