Tunable light lasing in dye doped ferroelectric liquid crystals

• Applicant: Professor Dr. Wolfgang Haase
• Subject Area: Condensed Matter Physics
• Term: from 2003 to 2008
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5404206

This project is devoted to the investigation of the tuning of the lasing properties of dye doped ferroelectric liquid crystals. Ferroelectric liquid crystals represent themselves a 1D periodic structure due to the deformed helix ferroelectric liquid crystal effect (DHF). The dye doped in such materials show the inhibitation of spontaneous emission inside such structures. The DHF electrooptical effect has three attractive properties for photonic crystals applications: 1) fast response time laying in microseconds range (~100µs), 2) rather strong optical anisotrophy (delta n ~ 0.2), 3) variation of the helix periodicity under application of an electric field. Therefore, it looks perspective to utilize dye doped DHF mixtures as electrically tunable mirrorless lasing materials. In scope of this project, DHF materials with a helix pitch laying in the visible and near infrared range with strong optical anisotropy (delta n ~ 0.2) will be prepared and doped with laser dyes (e.g. Coumarin 500, DCM, Rhodamine 590, Kiton Red 620). Cells with homeotropic alignment of these mixtures will be fabricated. The task of the project is to reveal the dependence of the parameters of the emission spectra of the DHF materials on the voltage applied to the cells, the properties of the DHF mixtures and the excitation energy.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1113: Photonic Crystals