Mouse Tissue Imaging by Random Laser of Plasmonic Two-Dimensional Array

Abstract

Given the major applications of high-resolution and non-destructive bio-imaging, a plasmonic waveguide-assisted imaging system based on random lasing is proposed here by helping micro-ring arrays covered with the gold/graphene layer and Rh6G dye. In order to achieve this objective, we employ a laser writing system to create micro-ring arrays and subsequently cover them with a plasmonic gold thin film using a sputtering machine. Additionally, the chemical vapor deposition method is employed to generate the graphene layer. To use this medium as random laser active media, we cover it with Rh6G dye and PVP polymer as the top high index layer to get more localization of light. After theoretically and experimentally evaluating the plasmonic substrate, we use the second harmonic generation of Nd:YAG laser as the source and record the random lasing of the sample under 45° via spectrometer. Our results show that the samples without the PVP layer yield a coherent random laser with about 6 nm and 1.4 nm in the full width at half maximum (FWHM) and threshold energy of 3.17 mJ and 1.42 mJ for concentrations 10⁻⁵ and 10⁻⁴, respectively, while finding that the laser threshold and FWHM are decreased by the sample with PVP layer reaching from 2.62 mJ and 5 nm to 1.95 mJ and 1.2 nm, respectively. This corresponded to the simulation part, in which the PVP layer enhanced the field amplitude significantly. Finally, we record the images of mouse tissue by the CCD camera. These findings provided a simple and efficient way for the realization of low-threshold random lasers at low cost.