Breaking the total internal reflection far above a critical angle (i.e., outcoupling deep-trap guided modes) can dramatically improve existing light-emitting devices. Here, we report a deep-trap guided modes outcoupler using densely arranged microstructured hollow cavities. Measurements of the leaky mode dispersions of hollow-cavity gratings accurately quantify the wavelength-dependent outcoupling strength above a critical angle, which is progressively improved over the full visible spectrum by increasing the packing density. Comparing hollow- and filled-cavity gratings, which have identical morphologies except for their inner materials (void vs. solid sapphire), reveals the effectiveness of using the hollow-cavity grating to outcouple deep-trap guided modes, which results from its enhanced transmittance at near-horizontal incidence. Scattering analysis shows that the outcoupling characteristics of a cavity array are dictated by the forward scattering characteristics of their individual cavities, suggesting the importance of a rationally designed single cavity. We believe that a hollow-cavity array tailored for different structures and spectra will lead to a technological breakthrough in any type of light-emitting device.
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http://dx.doi.org/10.1364/OE.26.00A450 | DOI Listing |
ACS Appl Mater Interfaces
February 2023
Department of Applied Physical Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States.
ACS Photonics
January 2019
Biosystems and Biomaterials Division, National Institute of Standards and Technology, Gaithersburg, MD 20899.
We examine multiphoton-produced optical signals waveguided through single ZnO nanorods (NRs) using a newly developed, scanning offset-emission hyperspectral microscopy (SOHM) technique. Specifically, we concurrently analyze waveguiding behaviors of sum-frequency generation (SFG), deep-trap emissions (DTE), and coherent anti-Stokes Raman scattering (CARS) occurring in individual ZnO NRs. SOHM acquires spectrally-indexed and spatially-resolved intensity maps/spectra of waveguided light intensity while excitation/emission collection positions and light polarization are scanned.
View Article and Find Full Text PDFBreaking the total internal reflection far above a critical angle (i.e., outcoupling deep-trap guided modes) can dramatically improve existing light-emitting devices.
View Article and Find Full Text PDFInorg Chem
May 2018
Graduate School of Human and Environmental Studies , Kyoto University, Kyoto 606-8501 , Japan.
Persistent luminescence (PersL) imaging without real-time external excitation has been regarded as the next generation of autofluorescence-free optical imaging technology. However, to achieve improved imaging resolution and deep tissue penetration, developing new near-infrared (NIR) persistent phosphors with intense and long duration PersL over 1000 nm is still a challenging but urgent task in this field. Herein, making use of the persistent energy transfer process from Cr to Er, we report a novel garnet persistent phosphor of YAlGaO codoped with Er and Cr (YAG G:Er-Cr), which shows intense Cr PersL (∼690 nm) in the deep red region matching well with the first biological window (NIR-I, 650-950 nm) and Er PersL (∼1532 nm) in the NIR region matching well with the third biological window (NIR-III, 1500-1800 nm).
View Article and Find Full Text PDFSci Rep
September 2014
1] School of Computer Science, Fudan University, Shanghai 200433, China [2] Shanghai Key Lab of Intelligent Information Processing, Fudan University, Shanghai 200433, China.
Designing appropriate techniques to effectively control the trapping process in complex systems towards desirable efficiency is of paramount importance in the study of trapping problem. In this paper, we present three different methods guiding trapping process in a scale-free small-world network with a deep trap positioned at an initial node. All the proposed approaches dominate the trapping process by varying the transition probability of random walks.
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