Control of emission diffraction angles and laser threshold in mixed-order sampled distributed feedback laser with organic gain media

摘要

The control of laser emission angles in laser devices is essential for many optoelectronic and photonic applications such as optical sensing and displays. In this context, we studied the light diffraction pattern of laser beams in a one-dimensional sampled distributed feedback resonator having organic gain media. The gratings consist of the repetition of supercells having a mixed-order sampled grating in which 1st-order gratings surround a 2nd-order grating. The experimental results showed that the diffraction angles of the laser beams are quite diverse depending on the supercell structures. We demonstrate that the interval of the diffraction angle (theta) of the laser beams is inversely proportional to the length of the supercell experimentally and theoretically. By tuning the length of supercells as well as the length of 1st-order and 2nd-order regions, the interval theta was tuned from 0.1 to 43 with the different arc emission patterns. With the reduction of theta, i.e., the longer 1st-order region, a significant decrease in the laser threshold was obtained, resulting in the lowest lasing threshold of 2.5 +/- 0.1 mu J/cm(2) with similar to 3.5 ns of a long pulse width excitation source. Published under an exclusive license by AIP Publishing.