Modeling optical modes of in-plane liquid crystal lasers

Lasing in liquid crystals has been demonstrated in numerous con gurations and material systems. In most reports the laser light is emitted perpendicular to the liquid crystal layer, using a chiral liquid crystal layer which exhibits a helical structure with a periodicity that gives rise to a stop band in the visible spectrum. The emission of light can then be modeled with one-dimensional models with reasonable accuracy. In the last few years also in-plane lasers have been demonstrated, for example by using a lying helix arrangement. The accurate optical modeling of the light generation in such systems is complex because the materials are optically anisotropic and the con guration should be modeled as two-dimensional. Advanced optical methods are necessary. For these simulations we rely on nite-element calculations of the optical modes in periodic two-dimensional structures including full position dependent anisotropy. The optical modes in a lying helix con guration are calculated as a proof-of-principle for this simulation method. Several interesting features of the optical modes in these structures are found.