Liquid crystalline chromophores for photonic band-edge laser devices

Stephen M. Morris, Malik M. Qasim, Damian J. Gardiner, Philip J.W. Hands, Flynn Castles, Guoli Tu, Wilhelm T. S. Huck, Richard, H. Friend, Harry J. Coles

Research output: Contribution to journalArticlepeer-review


We present results on laser action from liquid crystal compounds whereby one sub-unit of the molecular structure consists of the cyano-substituted chromophore, {phenylene-bis (2-cyanopropene)}, similar to the basic unit of the semiconducting polymer structure poly(cyanoterephthalylidene). These compounds were found to exhibit nematic liquid crystal phases. In addition, by virtue of the liquid crystalline properties, the compounds were found to be highly miscible in wide temperature range commercial nematogen mixtures. When optically excited at 355 nm, laser emission was observed in the blue/green region of the visible spectrum (480–530 nm) and at larger concentrations by weight than is achievable using conventional laser dyes. Upon increasing the concentration of dye from 2 to 5 wt.% the threshold was found to increase from Eth = 0.42 ± 0.02 uJ/pulse (~20 mJ/cm2) to Eth = 0.66 ± 0.03 uJ/pulse (~34 mJ/cm2). Laser emission was also observed at concentrations of 10 wt.% but was less stable than that observed for lower concentrations of the chromophore.
Original languageEnglish
Pages (from-to)837-842
JournalOptical Materials
Issue number5
Early online date25 Dec 2012
Publication statusPublished - Mar 2013


  • Liquid crystals
  • Lasers
  • Dyes

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