To clarify how micro-LED far-field light distributions differ from Lambertian distributions owing to small-sized-structure effects, the light distribution of a micro-LED was simulated via the ray-tracing method in this study. Specifically, considering material absorption, far-field light distribution, and light-output efficiency, we studied micro-LEDs as a function of size. We found that the light distribution is the most uniform and the efficiency is the highest when the size is the smallest under certain conditions. Under other conditions, with increasing sapphire size, the luminous efficiency first increases and then decreases. The luminous efficiency is the highest when the thickness is 30 µm. Under certain other conditions, as the diameter of the micro-sphere structure on the sapphire increases, the luminous efficiency first increases and then decreases.
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http://dx.doi.org/10.3390/ma15248854 | DOI Listing |
All-inorganic perovskite materials have been widely used in various devices, including lasers, light-emitting diodes (LEDs), and solar cells, due to their exceptional optoelectronic properties. Devices utilizing high-quality single crystals are anticipated to achieve significantly enhanced performance. In this work, we present a high-performance vertical cavity surface emitting laser (VCSEL) based on a single-crystal CsPbBr microplatelet, fabricated through a simple solution process and sandwiched between two distributed Bragg reflector (DBRs).
View Article and Find Full Text PDFComplete 2π cycling of a phase around a phase singularity leads to a rapid phase variation in the nearby zones and forms a sharp local -vector peak. In this paper, the intensity distribution in the spatial domain is transformed into a -vector distribution in the wave vector domain, and we prove that the local -vector peak is generated at the point of minimum light field intensity. The local -vector peak is sharper when the minimum point is closer to the phase singularity.
View Article and Find Full Text PDFDynamic transverse mode instability (TMI) has become one of the primary limitations for power scaling of high-power fiber lasers. Experimental evidence has shown that static mode degradation can suppress the dynamic TMI effect. This study reveals the physical mechanisms behind the mitigation of dynamic TMI in two-mode fiber lasers through static mode degradation.
View Article and Find Full Text PDFWe present the first, to our knowledge, metasurface holographic display method with exceptional fidelity and minimal edge noise, based on highly uniform flat-top light generated by a digital micromirror device (DMD). Based on the error-diffusion algorithm and iterative refinement process, the amplitude distribution of the initial Gaussian light was dynamically closed-loop modulated, and the standard difference of the intensity of the 3 mm diameter center flat-top beam was reduced to less than 3.4%.
View Article and Find Full Text PDFIn this work, a five-mode erbium-doped waveguide amplifier with low differential modal gain (DMG) is first proposed. A novel, to the best of our knowledge, gain equalization scheme for synergistic reconfiguration of refractive index and concentration doping is adopted to equalize the modal gains based on the dual-layer ring core structure. NaYF:5%Gd,20%Yb,2%Er@NaYF nanoparticles are synthesized by annealing treatment to improve the emission spectral properties and the concentration doped in a host core material.
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