The influence of photoluminescence (PL) spectra from two same-sized zinc oxide (ZnO) microspheres (MS), made by hydrothermal growth, coupling with each other is studied. It is shown that the difference of the PL spectra between single ZnO MS and coupling ZnO MSs can be observed. Coupled ZnO MSs leads to peak splitting of whispering gallery modes (WGMs) for both TE and TM polarization. The PL spectra were obtained by illuminating coupled ZnO MSs directly by 325 nm laser source via a micro-PL setup. First, we inject the laser into the one of the coupling ZnO MSs with 1.72 μm diameter, the PL spectra has few difference between single ZnO MS because the other MS makes less influence on the spherical resonator. Second, by injecting the laser which covers the coupling ZnO MSs, it’s surprising that the PL spectra shows various splitting peaks in the visible region. The phenomenon tells these two coupling MSs lose their symmetry which exist if they are separated, thus, the angular momentum of one ZnO MS is destroyed by another attached ZnO MS. To sum up, the PL spectra of ZnO MS is sensitive to the surface-decorated particles, which can be applied in biosensing to detect various molecules.

Date Published: 25 February 2020
PDF: 6 pages
Proc. SPIE 11302, Light-Emitting Devices, Materials, and Applications XXIV, 113021R (25 February 2020); doi: 10.1117/12.2546097

Published in SPIE Proceedings Vol. 11302:
Light-Emitting Devices, Materials, and Applications XXIV
Jong Kyu Kim; Michael R. Krames; Martin Strassburg, Editor(s)