Distributed feedback lasing from electrically tunable dye-doped polymer–liquid crystal transmission gratings

In the present work we report low-threshold distributed feedback (DFB) lasing from electrically tunable holographic polymer–liquid crystal transmission gratings of POLIPHEM type doped with pyrromethene 567. Due to their uniform droplet-free micro-morphology, the POLIPHEM gratings possess high diffraction efficiency and excellent optical quality. Second-order lasing with a threshold of ~0.8 µ J/pulse and a bandwidth of ~1 nm was achieved under the excitation of a frequency-doubled Nd:YAG laser operating at 532 nm. The laser emission wavelength was tuned from 572–625 nm by varying the grating period. Application of an electric field switches off or tunes the lasing intensity. An electrically-induced blue-shift of the output laser emission was observed.