Tunable light lasing in dye doped ferroelectric liquid crystals

本课题主要研究掺杂铁电液晶的激光调谐特性。由于螺旋形铁电液晶效应（DHF）的影响，铁电液晶表现为一维周期结构。在这种材料中掺杂的染料显示出这种结构内部自发发射的抑制作用。DHF电光效应有三个吸引光子晶体应用的特性：1)响应时间在微秒范围内（~100µs）， 2)较强的光学各向异性（δ n ~ 0.2）， 3)电场作用下螺旋周期的变化。因此，利用染料掺杂的DHF混合物作为电可调谐无反光镜激光材料是有前景的。在本项目范围内，将制备具有强光学各向异性（δ n ~ 0.2）的可见和近红外范围内螺旋螺距的DHF材料，并使用激光染料（如香豆素500、DCM、罗丹明590、Kiton Red 620）进行掺杂。将制备具有这些混合物的各向同性排列的细胞。该项目的任务是揭示DHF材料的发射光谱参数与施加在电池上的电压、DHF混合物的性质和激发能的依赖关系。

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.