White light induced photo-thermal switching in a graphene-flake-mixed ZnO nanoparticle random laser

Abstract

We experimentally demonstrate lasing mode switching within a graphene-flake-mixed ZnO nanoparticle film, in which the lasing suppression is observed when white light is illuminated on the film. The similar changes are also observed by changing the temperature of the same sample (about 30°C increase form room temperature), while no lasing suppression is observed in a ZnO nanoparticle film without graphene flakes. In addition, we also observe that a thin glass substrate coated by a graphene-flake-mixed ZnO nanoparticle film shows a bend toward the film-coated side with increasing the white light intensity, due to the negative thermal expansion of graphene flakes. From these results, we consider that, beside the temperature dependent ZnO emission property, the photothermal response of graphene flakes is the dominant key for our observed lasing mode changes, in which the local structural change in a graphene-flake-mixed ZnO nanoparticle film would be induced by the white light absorption of graphene flakes. This study suggests the possibility to provide a method to remotely and non-invasively control and tune the lasing modes by external white light illumination.

Unidirectional single-mode lasing realization and temperature-induced mode switching in asymmetric GaN coupled cavities

“…To conveniently and efficiently control the coupling process, thermal effects induced gain switching is a commonly used method. 38,39 It can be used for real time, in situ , and the fast tuning of the excitation modes of the coupled cavities. As describe previously, quasi-single-mode lasing can be obtained based on the Vernier effect in coupled cavities at room temperature.…”

Influence of Al doping on random lasing in ZnO nanorods

“…Lasing from nanoscale devices, specifically random lasers have the added advantage of lasing without the need of a conventional cavity made of mirrors whereby the "cavity" is made of the scattering random media [1]. In coherent random lasers, multiple modes of lasing appears above the broad spontaneous emission peak [2][3][4][5][6]. Various method have been proposed to reduce the threshold in these random lasers such as by laser-induced hydrothermal synthesis [7], introducing point defects using polymer particles [8], utilizing defect pits [9], tapering nanowires [10], reducing crystallite size [11], using colloidal nanoparticles [12], gold nanoparticles [13] etc.…”

Resonant random laser emission from graphene quantum dots doped dye solution

“…al. employed graphene flakes to switch and tune a ZnO NP-based-RL with white light illumination [15]. In another similar attempt in 2012, hybrid structure of graphene oxide nanoflakes/ZnO nanorods was suggested to enhance the RL action from ZnO nanorods by the assistance of graphene surface plasmons [16].…”