Visible whispering gallery mode lasing via Li⁺ ion doped ZnO microspheres

Here we have fabricated ZnO based microcavity as optical resonator to achieve whispering gallery mode (WGM) luminescence through visible excitations. We have observed defect related WGM emissions by individual ZnO microsphere through visible laser excitations of 532 nm wavelength. Further, in order to get visible stimulated emissions, we have considered the doping of 2 mol.% of monovalent (Li+) ion to increase the number of defects in ZnO. Nevertheless, here the ZnO and 2 mol.% Li doped ZnO (LiZnO) microcavities (microspheres) are synthesized by using hydrothermal synthesis technique. Here we have considered four distinguished 2 mol.% Li-ZnO microspheres to check the consistency of the stimulated emission behavior. We have observed that the stimulated emissions are achieved through all the four Li-ZnO microspheres at threshold pumping power density of 48 mW/cm2 of the laser source. Therefore, we have proposed these doped microresonators for their promising applications to design the WGM based visible laser cavities. (c) 2020 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the Second International Symposium "Functional Nanomaterials in Industrial Applications: Academy-Industry Meet".