Surface roughness induced random lasing in bio-polymeric dye doped film

Here we report on the surface roughness induced random lasing phenomenon observed in thin film of biophotonic matrix – an modified deoxyribonucleic acid with cationic surfactant cetyltrimethylammonium chloride, doped with Rhodamine 6G laser dye. The random lasing was achieved using doubled in frequency Nd:YAG nanosecond pulse laser as a source of excitation. The experiments were carried out for different lengths of excitation areas resulting in lasing fluence threshold reduction from 16.6 mJ/cm2 down to 33 μJ/cm2. Using Fast Fourier Transformation analysis of random lasing spectra an average resonator length was estimated to amount 37 μm.