Dye-doped CLC-lasers: Interdependence of spectral and angular characteristics and boundary conditions of the active layer

We have studied the spectral and angular emission characteristics of a cholesteric liquid crystal (CLC) laser under specific conditions of its planar orientation. It is discovered that the orthogonal orientation of directors on substrates greatly improves the lasing spectrum and the angular divergence. A shift of the lasing spectrum and an increase in the lasing threshold under such conditions can testify to the presence of a defect in such structure, though no dip in the spectrum is registered. The origin of the ring structure of a laser beam is studied, and it is established that this structure is caused by the excitation of the lasing on higher axial modes.