Distributed-feedback laser based on low-scattering and high-gain holographic polymer dispersed liquid crystal grating

In this paper, we utilize the acrylate monomer of low functionality to fabricate a holographic polymer dispersed liquid crystal grating with polymer-scaffolding morphology. It is effective to reduce the scattering loss in the grating which acts as a resonator in distributed-feedback laser since there is no droplet of liquid crystal. Moreover, the use of the monomer with high refractive index (RI) ensures the formation of grating with high RI modulation and, correspondingly, high feedback gain. For these two factors mentioned above, an excellent laser property is obtained from the dye-doped laser pumped by Nd:YAG pulse laser at 532 nm. A spectral linewidth of 0.3 nm is observed at pump energy threshold 0.8 mu J/pulse and a conversion efficiency of 1.2% is achieved at operating wavelength 635 nm. The laser performance is improved in some aspects such as threshold energy, linewidth and conversion efficiency to some extent compared with those reports proeviously.