The investigation of dye-doped liquid crystal systems for lasing applications has become a burgeoning topic in
recent years. To date, reports have been made of the tunability of cholesteric liquid crystal lasers by means of
temperature, photochemical processes and mechanical forces. The application of an in-plane electric field on a
cholesteric liquid crystal results in an unwinding and elongation of the cholesteric pitch. This change in pitch
length shifts the reflection band of the cholesteric liquid crystal. We report on the tunability of a cholesteric
liquid crystal laser in an in-plane switching mode cell. Tunabilities of up to 15 nm have been achieved in these
cells. Electrical tuning methods have significant advantages over the other techniques by which cholesteric lasers
can be tuned, especially with regards to the potential applications of liquid crystal lasers.
We investigate the fabrication of holographic polymer dispersed liquid crystals (H-PDLCs) for use as switchable laser cavities. H-PDLCs are liquid crystal and polymer dispersions used in grating applications for displays, optical communications and optical security. By controlling the pitch of the H-PDLC and the laser dye used, we are able to fabricate a tunable laser. H-PDLCs were made in both reflection and transmission modes to vary the method by which lasing action occurs. The dye-doped H-PDLCs were pumped with nanosecond pulses from a laser with emission at 532 nm and a power of approximately 6 mJ. Lasing action was observed using a spectrometer from the H-PDLC grating; peak wavelengths occurred over a range of wavelengths, depending on the dye used, with the full width of the emission peaks approximately 6-8 nm at half maximum. The lasing action can be turned on and off by the application and removal
of an electric field due to the properties of an H-PDLC. Furthermore, we investigate multidimensional architectures and quasicrystal symmetries for lasing applications. Applications for these cells include use in small-scale portable devices requiring a tunable laser source.