A strain-gauge random laser

We describe a random laser that uses the ZnO nanorods randomly orientated on a flexible polyimide (PI) substrate as disorderedly optical scatterers to stimulate coherent random lasing actions. Repeatable and reversible tuning of spectral emission is demonstrated by exerting a bending strain on the PI substrate, which enables us to activate the random laser on either below or above the lasing threshold. Furthermore, our random laser functions as a stable and durable optical strain gauge with a gauge factor of ≈37.7 ± 5.4 under a bending strain of 40%, which is comparable to that of traditional electrical strain gauges. The study validates that the reported strain-gauge random laser is able to be used in certain fields where the electrical gauge is restricted and the optical gauge is considered to preferable as an alternative solution.