The dataset contains experimental methodology for the fabrication of Blue Phase monocrystals doped with laser dyes and characterization measurements.
Objectives: To evaluate the lasing capabilitirs of Blue Phase liquid crystals when doped with laser dyes.
Methods: 3D monocrystalline Blue Phase photonic crystals were doped with P580 laser dye. Blue phase (BP) precursor mixtures were formulated using an in-house nematic host composed of fluorinated terphenyls, biphenyls, and cyclohexylbiphenyls, combined with mesogenic monomers and the chiral dopant ISO(6OBA)₂. The dopant concentration was tuned to control BP lattice orientation and lattice constant following a previously reported approach enabling the growth of large BP monocrystals with predictable crystallographic orientation. Weak anchoring conditions were achieved using Nylon alignment layers, which promoted uniform monodomain crystals. Two mixtures were prepared with ISO(6OBA)₂ concentrations of 5.3 wt.% and 5.0 wt.%. Pyrromethene 580 laser dye was incorporated at 1 wt.% from chloroform solution. Mixture compositions were optimized to suppress the formation of BPI(200) domains and favor single BPI(110) monocrystals.
Liquid crystal cells were fabricated using ultraflat indium-tin-oxide coated glass substrates separated by 10 μm spacers. Alignment layers were deposited, thermally conditioned, and rubbed in an antiparallel configuration. The mixtures were filled in the isotropic phase by capillary action. After thermal characterization, the BP structures were polymer stabilized by UV irradiation at 365 nm (4 mW cm⁻²).
Phase transitions were investigated during cooling using polarized optical microscopy with temperature control. Crystal orientation and lattice parameters were determined from Kossel patterns obtained in the conoscopic configuration and compared with simulations modeling BPI (BCC) and BPII (simple cubic) structures.
Lasing experiments were performed using pulsed 532 nm Nd:YAG excitation. Emission spectra and angular emission patterns were recorded using a fiber-coupled spectrometer and CCD camera. Angle- and polarization-resolved measurements were performed using a Fourier-space microscopy setup.
Results: Directional lasing from millimeter-scale stabilized monocrystalline BP photonic crystals is shown a significant advance, as only random lasing from polycrystalline samples has been previously observed. These structures exhibit directional distributed lasing, with emission guided through the crystalline lattice, producing highly directional and circularly polarized laser output. The laser action is attributed to resonant polarization modes of the BP lattice, characterized by angular dispersion and strong chiral selectivity. These findings establish BP monocrystals as viable platforms for integrated photonic systems and mirrorless lasing.
(2025-09-18)
