Magnetic-field tuning of whispering gallery mode lasing from ferromagnetic nematic liquid crystal microdroplets.

We report magnetic field tuning of the structure and Whispering Gallery Mode lasing from ferromagnetic nematic liquid crystal micro-droplets. Microlasers were prepared by dispersing a nematic liquid crystal, containing magnetic nanoparticles and fluorescent dye, in a glycerol-lecithin matrix. The droplets exhibit radial director structure, which shows elastic distortion at a very low external magnetic field. The fluorescent dye doped ferromagnetic nematic droplets show Whispering Gallery Mode lasing, which is tunable by the external magnetic field. The tuning of the WGM lasing modes is linear in magnetic field with a wavelength-shift of the order of 1 nm/100 mT. Depending on the lasing geometry, the WGMs are red- or blue-shifted.

[1]  Paul J. Ackerman,et al.  Biaxial ferromagnetic liquid crystal colloids , 2016, Proceedings of the National Academy of Sciences.

[2]  I. Musevic,et al.  Liquid-crystal micro-photonics , 2016 .

[3]  Yuliya Semenova,et al.  Magnetic-field sensor based on whispering-gallery modes in a photonic crystal fiber infiltrated with magnetic fluid. , 2015, Optics letters.

[4]  Paul J. Ackerman,et al.  Ferromagnetic Switching of Knotted Vector Fields in Liquid Crystal Colloids. , 2015, Physical review letters.

[5]  S. Dhara,et al.  Temperature dependence of equilibrium separation and lattice parameters of nematic boojum-colloids , 2015 .

[6]  S. Dhara,et al.  Magnetodielectric and magnetoviscosity response of a ferromagnetic liquid crystal at low magnetic fields , 2015 .

[7]  Wei Hu,et al.  Wide tunable lasing in photoresponsive chiral liquid crystal emulsion , 2015 .

[8]  M. Škarabot,et al.  Topological defect transformation and structural transition of two-dimensional colloidal crystals across the nematic to smectic-A phase transition. , 2015, Physical review. E, Statistical, nonlinear, and soft matter physics.

[9]  N. Viswanathan,et al.  Detection of phase transitions from the study of whispering gallery mode resonance in liquid crystal droplets , 2015 .

[10]  N. Osterman,et al.  Magneto-optic and converse magnetoelectric effects in a ferromagnetic liquid crystal. , 2014, Soft matter.

[11]  M. Drofenik,et al.  Ferromagnetism in suspensions of magnetic platelets in liquid crystal , 2013, Nature.

[12]  T. Mo,et al.  Optically tunable/switchable omnidirectionally spherical microlaser based on a dye-doped cholesteric liquid crystal microdroplet with an azo-chiral dopant. , 2013, Optics express.

[13]  S. Žumer,et al.  Assembly and control of 3D nematic dipolar colloidal crystals , 2013, Nature Communications.

[14]  M. Drofenik,et al.  Chemical Substitution—An Alternative Strategy for Controlling the Particle Size of Barium Ferrite , 2012 .

[15]  M. Humar,et al.  Surfactant sensing based on whispering-gallery-mode lasing in liquid-crystal microdroplets. , 2011, Optics express.

[16]  P. Hands,et al.  Paintable band-edge liquid crystal lasers. , 2011, Optics express.

[17]  M. Humar,et al.  3D microlasers from self-assembled cholesteric liquid-crystal microdroplets. , 2010, Optics express.

[18]  Igor Muševič,et al.  Electrically tunable liquid crystal optical microresonators , 2009 .

[19]  Miha Ravnik,et al.  Two-Dimensional Nematic Colloidal Crystals Self-Assembled by Topological Defects , 2006, Science.

[20]  O. Lavrentovich,et al.  Elasticity-mediated self-organization and colloidal interactions of solid spheres with tangential anchoring in a nematic liquid crystal. , 2005, Physical review letters.

[21]  Holger Stark,et al.  Physics of colloidal dispersions in nematic liquid crystals , 2001 .

[22]  Shu-hsia Chen,et al.  Simulation of Normal Anchoring Nematic Droplets under Electrical Fields , 1999 .

[23]  John H. Erdmann,et al.  Configuration transition in a nematic liquid crystal confined to a small spherical cavity. , 1990, Physical review letters.