Thermal emission engineering with ability to realize spectral and spatial selection has attracted great attention in recent years. Nanophotonic control of thermal radiation has demonstrated ...narrowband thermal emitter but with high angle-sensitivity and diffuse thermal emitter but with low quality factor (
). Here, we demonstrate a simultaneous narrowband, diffuse thermal emitter consisting of 80 nm (<
/100) thick Ge nanostructures on a silicon carbide (SiC) phononic material. Based on surface phonon polaritons, a spectral coherent emission with a high
factor of 101 is achieved at ∼10.9 μm wavelength in experiment. Furthermore, this phonon-mediated nanostructure provides spatial control with strong diffuse thermal emission with a full angle at half maximum of 70°. Additionally, the emission wavelength and intensity are tuned by replacing Ge with phase change materials (Ge
Sb
Te
and In
SbTe
). The designed narrowband diffuse thermal emitter offers new perspectives for the engineering of emission and paves the way for infrared applications, including thermal sources, radiative cooling, infrared sensing, and thermal photovoltaics.
In order to study the laser plasma instabilities (LPIs) in the context of some novel six-side laser-driven indirect designs like the six-cylinder-port hohlraum and the three-axis cylindrical ...hohlraum, where the laser beams inject in hohlraum with a large angle. LPI experiments in cylindrical hohlraum with only outer beams were designed and performed based on the current laser arrangement condition of SGIII laser facility for the first time. Stimulated Brillouin backscatter (SBS) was found to be the dominant instability with high instantaneous reflectivity in experiments. A typical feature was obtained in the time-resolved spectra of SBS, which maintained similar for different laser intensities of the interaction beam. The experimental data are analyzed by the hydrodynamic simulations combined with HLIP code, which is based on the ray-tracing model. By analysis of experimental data, it is argued that the mixture of gas and Au in the region of their interface is important to SBS, which indicates the need for the mixture model between the filled gas and the high Z plasma from hohlraum wall in the hydrodynamic simulations. Nonlinear saturation of SBS as well as the smoothed beam are also discussed here. Our effective considerations of the ions pervasion effect and the smoothed beam provide utilitarian ways for improvement of the current ray-tracing method.
CsPbBr3 nanoparticles uniformly distributed on reduced graphene oxide (rGO) to form CsPbBr3/rGO nanocomposites are synthesized by a facile method. Their corresponding optical and X-ray photon ...response are investigated. UV–visible absorption spectra and photoluminescence measurements confirm that loading CsPbBr3 nanoparticles with an even distribution onto rGO surface can enhance the absorption and photon-generated carrier transportation. Thus, a significant enhancement in optical and X-ray photon response is demonstrated in CsPbBr3/rGO nanocomposites as compared with pure CsPbBr3 nanoparticles. Clear conductive switching phenomenon with a state conversion between “on” and “off” is also observed under the intermittent x-ray exposure. These results may provide a new potential application of CsPbBr3/rGO nanocomposites for X-ray photon detection.
•CsPbBr3 nanoparticles are uniformly distributed on reduced graphene oxide (rGO).•CsPbBr3/rGO nanocomposites could enhance photon-generated carrier transportation.•A significant enhancement of X-ray photon response was demonstrated.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Switchable thermal emission in the long-wave infrared (LWIR, 8–14 μm) range is of great significance in applications like thermal detection, radiative cooling, and infrared camouflage. Existing ...methods for switchable LWIR emission apply photonic structures incorporating smart materials, which either require a continuous input power or produce limited emissivity contrasts. In this study, two nonvolatile high-contrast switchable emitters over the whole LWIR range have been proposed utilizing the drastic permittivity change of In3SbTe2 (IST) upon crystallization. One switchable emitter exhibits negative differential emissivity (Δε N,8–14 μm ≈ −0.75, emissivity decreases with temperature) and is experimentally applied to infrared camouflage; the other shows positive differential emissivity (Δε P,8–14 μm ≈ 0.83, emissivity increases with temperature) and demonstrates its capability in thermal management. The demonstrated characteristics of IST provide a new route for realizing differential emissivity and make the IST-based emitters highly promising for applications such as infrared camouflage and thermal management.
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The Q factor in a quasi-BIC-based optical device can approach infinity and has therefore been attracting the attention of many researchers in recent years. However, this mode is barely applied to ...absorbers since it mainly tunes the radiative loss. The resonant wavelength of quasi-BICs normally couples with the Q factor, and it is difficult to independently tune one of them while maintaining the other, which weakens the flexibility of tuning. In this work, a quasi-BIC-based high-Q perfect absorber with some unique features is proposed. It shows a decoupled relationship between the resonant wavelength and the Q factor such that these two properties can be independently tuned by changing different structure parameters. In addition, both radiative and resistive losses are tunable. An easy method is proposed to design a perfect absorber with different resonant wavelengths and different Q factors, and a near-infrared perfect absorber with a Q factor as high as 5.13 × 105 is designed. This work proposes a method to tune the quasi-BIC mode, thereby introducing a new paradigm for the design of a high-Q perfect absorber.
CsPbBr3 nanoparticles uniformly distributed on reduced graphene oxide (rGO) to form CsPbBr3/rGO nanocomposites are synthesized by a facile method. Their corresponding optical and X-ray photon ...response are investigated. UV–visible absorption spectra and photoluminescence measurements confirm that loading CsPbBr3 nanoparticles with an even distribution onto rGO surface can enhance the absorption and photon-generated carrier transportation. Thus, a significant enhancement in optical and X-ray photon response is demonstrated in CsPbBr3/rGO nanocomposites as compared with pure CsPbBr3 nanoparticles. Clear conductive switching phenomenon with a state conversion between “on” and “off” is also observed under the intermittent x-ray exposure. These results may provide a new potential application of CsPbBr3/rGO nanocomposites for X-ray photon detection.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
A recent experiment on the Shenguang III laser facility has applied open-end gold hohlraums with two gas pressures to study the movement of a plasma bubble. Under a laser intensity and width close to ...those of an ignition main pulse, the bubbles possess radial scales from several hundred to one thousand micrometers. An x-ray framing camera is used to measure the N-band x-ray images generated from the gold bubble plasma at different moments, from which the edge positions of the expanding bubbles are accurately acquired. The experimental results are simulated by an optimized two-dimensional radiation hydrodynamic code. Based on the classical average atom (AA) model, two phenomenological coefficients Cer and Cop are introduced into the code to correct the bubble evolution. Cer artificially redistributes the energies between radiation and matter, and Cop correlatively adjusts the plasma opacity. The bubble movement simulated by the novel phenomenological model agrees better with the measured result than that by the AA model. This work plays a critical role in our code improvements and advances the reliability of the hohlraum design.
The combination system of a pupil filter and an imaging system can achieve super-resolution. Aiming at exploring a method for designing and simulating such a super-resolving system, this paper ...introduced and discussed the pupil filter design theory at first. Then, based on the knowledge, a new continuous pupil filter and a corresponding imaging system were designed. The designed super-resolving factor G and Strehl ratio S were 0.7895 and 0.40, respectively. Finally, ZEMAX software was used to simulate the whole super-resolving system. The simulation results that G equaled to 0.7826 and S equaled to 0.3768, were reasonably smaller than the designed values. The results proved the validity and accuracy of this design and simulation procedure. With this method, it is possible to do risk assessment before production and reduce cost.
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Based on active optics, the zoom system design can no longer be confined to traditional methods of changing the distances between optical components for variable focal lengths. An all-reflective ...active zoom system with three mirrors is designed. The primary and third aspheric mirrors act as deformable mirrors to realize the transition among the different focal lengths by the curvature radius variation, while the second aspheric mirror is static. According to the third-order aberration theory and dimension calculations of the optical system requirements with the constraint limitations, the system's initial construction parameters can be achieved. This all-reflective active zoom system can realize zoom ratio is 3, focal length between 5 and 15mm, field-of-view of 10–27.8°, and wide working wavelength from the visible to infrared.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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