Gain-narrowing characteristics of fluorescent organic molecules with symmetrical or asymmetrical structures in a neat thin-film optical waveguide

We investigated gain-narrowing performance of fluorescent styrylbenzene and azomethyne derivatives in a neat thin-film optical waveguide by optical pumping. In particular, an extremely low-threshold for gain-narrowing was obtained with 4,4′-bis[4-(di-p-tolyl-amino)styryl]biphenyl (LD1), and the obtained threshold was comparable to the threshold of LD1 in the high efficient guest–host system previously reported. High symmetry of the molecular structure was important for the gain-narrowing performance.