Multiple-mode lasing at the band edge of dye-doped planar structures in dichromated gelatin film with gradient spacing, obtained by differential swelling of the gelatin during developing process, was demonstrated. The lasing intensity at λ = 560 nm, increases nonlinearly respect to the pumping energy at 532 nm laser light. Asymmetric fluorescence emissions, from gelatin side and substrate side, and one-sided mirrorless lasing were achieved. The polarization of lasing beam is linear which follows the polarization of the pumping beam. The spatial lasing profile was also recorded. The band edge is not well defined for a differential spacing layer structure compared with the periodic case. The density of states (DOS) near the band edge of the structure and its relation with the multiple las...[ Read more ]

Multiple-mode lasing at the band edge of dye-doped planar structures in dichromated gelatin film with gradient spacing, obtained by differential swelling of the gelatin during developing process, was demonstrated. The lasing intensity at λ = 560 nm, increases nonlinearly respect to the pumping energy at 532 nm laser light. Asymmetric fluorescence emissions, from gelatin side and substrate side, and one-sided mirrorless lasing were achieved. The polarization of lasing beam is linear which follows the polarization of the pumping beam. The spatial lasing profile was also recorded. The band edge is not well defined for a differential spacing layer structure compared with the periodic case. The density of states (DOS) near the band edge of the structure and its relation with the multiple lasing modes will be discussed.