Microtubular structured random lasers as microfluidic channels for multifunctional sensing

Random lasers (RLs) with a simple structure and low-cost properties have been recognized as an ideal analytical platform and are still challenging for liquid detecting, remaining beset for low sensitivity, complicated operation, and large analyte consumption. Here, inspired by a microfluidic sensor, a microtubule structured random laser for multifunctional sensing is demonstrated. The random laser is achieved resorting to a curly PMMA film with gain and scatterers embedded in it. By coupling the high-order WGM with a weak random scattering mode, a coherent random laser with a low threshold of 0.62 MW cm^-2 and a high Q factor of 4700 is obtained. The sensing process has been demonstrated based on two kinds of representative analytes of sucrose solution and TiO₂ NP suspension, which respond to the variation of gain and scattering. The RL sensor features fast detection, easy operation, and low cost, which may provide a new approach for their further applications in analytical microfluidic chip and disposable/pocket analytical instruments.