The effect of dopant and optical micro-cavity on the photoluminescence of Mn-doped ZnSe nanobelts

Pure and Mn-doped ZnSe nanobelts were synthesized by a convenient thermal evaporation method. Scanning electron microscopy, X-ray powder diffraction, energy dispersive X-ray spectroscopy and corresponding element mapping, and transmission electron microscope were used to examine the morphology, phase structure, crystallinity, composition, and growth direction of as-prepared nanobelts. Raman spectra were used to confirm the effective doping of Mn(2+) into ZnSe nanobelts. Micro-photoluminescence (PL) spectra were used to investigate the emission property of as-prepared samples. A dominant trapped-state emission band is observed in single ZnSe(Mn) nanobelt. However, we cannot observe the transition emission of Mn ion in this ZnSe(Mn) nanobelt, which confirm that Mn powder act as poor dopant. There are weak near-bandgap emission and strong (4)T(1) → (6)A(1) transition emission of Mn(2+) in single [Formula: see text] and [Formula: see text] nanobelt. More interesting, the (4)T(1) → (6)A(1) transition emission in [Formula: see text] nanobelt split into multi-bands. PL mapping of individual splitted sub-bands were carried out to explore the origin of multi-bands. These doped nanobelts with novel multi-bands emission can find application in frequency convertor and wavelength-tunable light emission devices

Controllable nonlinear propagation of partially incoherent Airy beams

The self-accelerating beams such as the Airy beam show great potentials in many applications including optical manipulation, imaging and communication. However, their superior features during linear propagation could be easily corrupted by optical nonlinearity or spatial incoherence individually. Here we investigate how the interaction of spatial incoherence and nonlinear propagation affect the beam quality of Airy beam, and find that the two destroying factors can in fact balance each other. Our results show that the influence of coherence and nonlinearity on the propagation of PIABs can be formulated as two exponential functions that have factors of opposite signs. With appropriate spatial coherence length, the PIABs not only resist the corruption of beam profile caused by self-focusing nonlinearity, but also exhibits less anomalous diffraction caused by the self-defocusing nonlinearity. Our work provides deep insight into how to maintain the beam quality of self-accelerating Airy beams by exploiting the interaction between partially incoherence and optical nonlinearity. Our results may bring about new possibilities for optimizing partially incoherent structured field and developing related applications such as optical communication, incoherent imaging and optical manipulations.Comment: 11pages,6 figure

Caustic analysis of partially coherent self-accelerating beams: Investigating self-healing property

We employed caustic theory to analyze the propagation dynamics of partially coherent self-accelerating beams such as self-healing of partially coherent Airy beams. Our findings revealed that as the spatial coherence decreases, the self-healing ability of beams increases. This result have been demonstrated both in simulation and experiment. This is an innovative application of the caustic theory to the field of partially coherent structured beams, and provides a comprehensive understanding of self-healing property. Our results have significant implications for practical applications of partially coherent beams in fields such as optical communication, encryption, and imaging.Comment: 9 pages, 4 figure

All-Dielectric Structural Coloration Empowered by Bound States in the Continuum

The technological requirements of low-power and high-fidelity color displays have been instrumental in driving research into advanced coloration technologies. At the forefront of these developments is the implementation of dye-free coloration techniques, which overcome previous constraints related to insufficient resolution and color fading. In this context, resonant dielectric nanostructures have emerged as a promising paradigm, showing great potential for high efficiency, remarkably high color saturation, wide gamut palette, and realistic image reproduction. However, they still face limitations related to color accuracy, purity, and simultaneous brightness tunability. Here, we demonstrate an all-dielectric metasurface empowered by photonic bound states in the continuum (BICs), which supports sharp resonances throughout the visible spectral range, ideally suited for producing a wide range of structural colors. The metasurface design consists of titanium dioxide (TiO2) ellipses with carefully controlled sizes and geometrical asymmetry, allowing versatile and on-demand variation of the brightness and hue of the output colors, respectively.Comment: Main text and supporting information, 40 pages, 4 Figures in the manuscript + 12 Figures in the supporting informatio