- 标题
- 摘要
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- 实验方案
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Nanoscopic Spotlight in a Spindle Semiconductor Nanowire
摘要： Theoretically, no matter how thin a nanowire is, it can transport light in the form of an evanescent field. However, in practice, the low propagation efficiency induced by complex dissipation makes light transport difficult to realize when the nanowire is distinctly thinner than ~λ/2. Accordingly, nanowire photonics research at such a scale is limited. Herein, light propagation was achieved in a very thin spindle nanowire (diameter below 70 nm), in which a nanoscopic spotlight formed. The nanowire output a maximum emission in the transverse dimension as small as ~53 nm. The finite-difference time-domain (FDTD) simulation implied that the increased dimension gradient near the tip induced a maximum leakage of the propagating light at a transverse feature, precisely determined by the intrinsic feature of the nanowire. Moreover, a spectrum splitter phenomenon was observed and demonstrated based on the wavelength-dependent light propagation behavior in such a nanowire. These results contribute to the rational design of nanoscopic near-field illuminant, optoelectric and photobiological probes with improved resolution largely superior to the so-called subwavelength level.
关键词： semiconductors,nanoscopic light,light waveguide,nanowires,photonic property
更新于2025-09-23 15:22:29
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Design and testing of an externally-coupled planar waveguide photobioreactor
摘要： Waveguides can be used to deliver light deep into algal photobioreactors, allowing the growth of algal biofilms with high areal yield. A current drawback of these reactors is their dependency upon artificial illumination. A more practical approach would be to use direct sunlight to illuminate the waveguide photobioreactor. In this paper a novel optical system is designed to grow algal biofilm using waveguides illuminated with external light using 3D-printed paraboloidal mirrors. It was found that the polygonal approximation of a compound parabolic trough was an effective mechanism for focusing external natural light, which could be constructed easily. It is also demonstrated that algae biofilm biomass productivity on the waveguide increases by a factor of 2.5 when operated in conjunction with mirrored troughs.
关键词： Photobioreactor,Solar concentrators,Algal biofilm,Non-imaging optics,Light waveguide
更新于2025-09-12 10:27:22