A team from NTT Basic Research Laboratories and NTT Photonics Laboratories, both in Atsugi, Japan, has reported directional lasing oscillation in 2-D organic photonic crystals. The effect, which the group describes in the March 5 issue of Applied Physics Letters, demonstrates that the feedback mechanism in the crystals differs from that in distributed feedback lasers.The researchers used electron-beam lithography and dry-etching techniques to pattern 40 samples of SiO2 on silicon, onto which they evaporated DCM:Alq3. When pumped with a 337-nm N2 laser, the samples lased at 600 to 680 nm, depending on the possible feedback mechanisms for four bandgaps.