Low threshold of distributed feedback lasers based on scaffolding morphologic holographic polymer dispersed liquid crystal gratings: reduced losses through Forster transfer 

Abstract

The threshold of distributed feedback (DFB) lasing from dye-doped holographic polymer dispersed liquid crystal (HPDLC) gratings was reduced using a guest–host (G–H) system. Different doping concentrations of the guest emitter 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM) in the host dye 1,3,5,7,8-pentamethyl-2,6-diethylpyrromethene-difluoroborate (PM567) were dispersed in the HPDLC transmission gratings. DFB lasing was observed in the pure host, the pure guest and in the G–H system. With the increase in doping concentration of the guest, the gain spectrum was redshifted. Through effective Forster energy transfer, we found that the lasing threshold was lowered to 1.35 μJ/pulse, which reduced by factor 2 compared to that without energy transfer process. This effect is attributed to the suppression of self-absorption at the lasing wavelength.

Keywords:

• holographic polymer dispersed liquid crystal
• distributed feedback organic laser
• Forster energy transfer
• low threshold

Acknowledgements

The authors thank the Natural Science Foundation of China (grant Nos [11174274], [11174279], [61205021], [11204299], [61378075], [61377032]) for their support.