Executive Summary : | Random lasers (RLs) have gained attention due to their unique features such as high spectral power density, low coherence, and replica symmetry breaking spin-glass phase. However, their potential applications are limited due to their omnidirectional emission and lack of control over output modes. To overcome this, an in-depth understanding of the properties of random lasing modes is required. Most random lasers studied thus far are based on distributed feedback mechanisms, with scatterers randomly distributed inside the gain medium and outside the gain region. This project aims to study the modes of non-distributed feedback optofluidic random lasers (NDFBORLs). Optofluidic random lasers (ORLs) have advantages such as mass production, ease of manipulation, and low cost. However, ORLs have scatterers distributed randomly inside the gain medium, making them weakly scattering systems due to low refractive index contrast. The presence of the gain medium and scatterers at the same spatial location limits their application as label-free sensors. separating the scatterers from the gain medium is advantageous for investigating lasing modes and developing label-free sensors by perturbing the light scattering process. This project will develop two types of NDFBORLs based on on-average-periodic and completely random scatterers with rectangular and circular device geometry. The study will help fill the gap in understanding random lasing modes from a conventional laser point of view and develop label-free sensors for sensing nano-particles and proteins. |