Ultrafast tunable filter in two-dimensional organic photonic crystal

A tunable filter made from a two-dimensional polystyrene photonic crystal is fabricated by focused ion-beam etching. The pump and probe scheme is adopted to measure tunability based on the picosecond optical Kerr effect. The response time of the tunable filter, approximately 10 ps, is within the measurement resolution. The maximum shift of optical channels is estimated to be 6 nm under excitation of 15.9 GW/cm2 pump intensity, which is in agreement with the theoretical prediction.