20.500.12556/RUL-178234 Whispering gallery mode study of phase transition and shape change in liquid crystal droplets We demonstrate that the Whispering Gallery Mode (WGM) lasing spectroscopy is a versatile high resolution tool to study the structure of interfaces of liquid crystalline (LC) droplets immersed in an immiscible fluid, such as water. The eigenfrequencies of WGMs in spherical microcavities are very sensitive to the refractive index profile in the nanometer thin interfacial region. This makes it possible to detect interfacial phenomena and temperature change in LC droplets with interferometric accuracy. We use 10–30 µm diameter droplets of a nematic liquid crystal labeled with a fluorescent dye and floating in water as an optical microcavity that sustains the WGMs. At the isotropic–nematic transition we observe wetting of the droplet's interface by a nanometer-thin layer of paranematic LC. Just below this transition, we observe red-shift and strong fluctuations of WGM spectra just before spherical droplet elongates into a fiber. The experiments are modeled with Finite-Difference Time-domain (FDTD) analysis of WGMs in nematic droplet and we find very good qualitative agreement. Whispering Gallery Mode spectroscopy liquid crystals liquid crystal droplets WGM spektroskopija tekoči kristali tekočekristalne kapljice true false true Angleški jezik Slovenski jezik Članek v reviji 2026-01-21 15:18:17 2026-01-21 15:18:17 2026-01-22 04:36:27 0000-00-00 00:00:00 2026 0 0 Str. 604-615 iss. 3 Vol. 22 2026 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 538.9 1744-6848 10.1039/D5SM01126D 264538627 d5sm01126d.pdf d5sm01126d.pdf 1 5690F9115246C649DB91D2CF05F490A4 b8ef06aa0f01d9e005d65dc959df58e3522bf9389eead3cc3da4973977ee2d81 12f64eb7-f6d4-11f0-bf92-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=225872 https://pubs.rsc.org/en/content/articlelanding/2026/sm/d5sm01126d 0 19fbe436-f6d4-11f0-bf92-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=225873 Fakulteta za matematiko in fiziko 0 0 0