sunlight. The features of an accurate radiative model, strong selective emission in the atmospheric transparency window, and broadband high reflectance to solar irradiation are each formulated individually and then configured collectively to accomplish this outcome. Because all of the successful examples of daytime radiative coolers possess high solar reflectivity, they are white or silver in color and are thus not visually appealing, [5][6][7]9] thereby restricting the possible installation locations and limiting their net cooling capacity. Although previous efforts have been paid to incorporate colors into the radiative cooler, [26] the research only dealt with theoretical calculations without experimental demonstrations, and structural optimization of colored radiative coolers has not been performed. Here, we present concepts and strategies for daytime radiative cooling systems that involve comparable attention to engineering design but with the goal of achieving systems that offer aesthetically desired colors and patterns and functional purposes, thus enabling more widespread installation. The experimental demonstration exhibits subambient cooling behaviors under a clear sky while preserving its color. The approaches reported here can address application concepts for wearable electronic devices whose operational temperature is lowered by radiative cooling. Figure 1a exhibits a schematic of a decorative colored passive radiative cooler (CPRC) for aesthetic purposes featuring areas with subtractive primary colors (i.e., cyan, magenta, and yellow) on a silvery background, where the latter area represents a conventional daytime radiative cooler. The CPRC consists of a SE comprising a bilayer of SiO 2 (650 nm) and Si 3 N 4 (910 nm), whose thicknesses are defined by extensive numerical optimization; and a metal reflector comprising an Ag film (100 nm) deposited on a silicon substrate (Figure 1b, left). Additional photonic nanostructures were inserted below the SE to generate vivid colors at specific desired areas (Figure 1b, right), which comprised a thin-film resonator composed of a metal-insulator-metal (MIM) structure. The MIM structure determined each color via interference in the 1D stacked layers, where the color generation was precisely controlled by tuning the thickness of the insulator layer (i.e., SiO 2 cavity) in the MIM.In this study, the MIM structure was chosen as the colorant structure because it provided minimal loss of solar reflectance and a narrow spectral width compared with other additive color filters such as metal gratings and 1D photonic crystals (1D PhC),Recently developed approaches in passive radiative cooling enable daytime cooling via engineered photonic structure layouts. However, the use of these daytime radiative coolers is restricted owing to their nonaesthetic appearance resulted from strong solar reflection. Therefore, this article introduces a colored passive radiative cooler (CPRC) capable of generating potential cooling power, based on a thin-film optical resonator embedded in ...
The low delivery efficiency of light‐responsive theranostic nanoparticles (NPs) to target tumor sites, particularly to brain tumors due to the blood–brain barrier, has been a critical issue in NP‐based cancer treatments. Furthermore, high‐energy photons that can effectively activate theranostic NPs are hardly delivered to the target region due to the strong scattering of such photons while penetrating surrounding tissues. Here, a localized delivery method of theranostic NPs and high‐energy photons to the target tumor using microneedles‐on‐bioelectronics is presented. Two types of microneedles and flexible bioelectronics are integrated and mounted on the edge of surgical forceps. Bioresorbable microneedles containing theranostic NPs deliver the NPs into target tumors (e.g., glioblastoma, pituitary adenoma). Magnetic resonance imaging can locate the NPs. Then, light‐guiding/spreading microneedles deliver high‐energy photons from bioelectronics to the NPs. The high‐energy photons activate the NPs to treat tumor tissues by photodynamic therapy and chemotherapy. The controlled thermal actuation by the bioelectronics accelerates the diffusion of chemo‐drugs. The proposed method is demonstrated with mouse tumor models in vivo.
The miniaturization of 3D depth camera systems to reduce cost and power consumption is essential for their application in electrical devices that are trending toward smaller sizes (such as smartphones and unmanned aerial systems) and in other applications that cannot be realized via conventional approaches. Currently, equipment exists for a wide range of depth-sensing devices, including stereo vision, structured light, and time-of-flight. This paper reports on a miniaturized 3D depth camera based on a light field camera (LFC) configured with a single aperture and a micro-lens array (MLA). The single aperture and each micro-lens of the MLA serve as multi-camera systems for 3D surface imaging. To overcome the optical alignment challenge in the miniaturized LFC system, the MLA was designed to focus by attaching it to an image sensor. Theoretical analysis of the optical parameters was performed using optical simulation based on Monte Carlo ray tracing to find the valid optical parameters for miniaturized 3D camera systems. Moreover, we demonstrated multi-viewpoint image acquisition via a miniaturized 3D camera module integrated into a smartphone.
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