Large area resonant feedback random lasers based on dye-doped biopolymer films

We report resonant feedback random lasing from dye-doped biopolymer films, consisting of a deoxyribonucleic acid-cetyltrimethylammonium (DNA-CTMA) complex doped with DCM dye. In the proposed devices, the optical feedback for random lasing is given by scattering centers randomly positioned along the edges of the active area. Scattering elements are either titanium dioxide nanoparticles or random defects at the interface between active polymer and air. Different emission spectra are observed, depending on the geometry of the excited area. A single random resonator with dimensions of 2.6 mm x 0.65 mm is fabricated and random emission with resonant feedback is obtained by uniformly pumping the full device.