Direct current (DC) electro-optical (EO) control of transmitted laser beam intensity based on EOcontrolled coherent light scattering and diffraction by stationary longitudinal texture pattern(LTP) is achieved in planar-oriented cells with a composite mixture of polymer-coated goldspherical nanoparticles (Au-NPs) with a mean diameter of about 12 nm and the room-temperaturenematic pentylcyanobiphenyl (5CB). At relatively low DC voltage of about 5 V, the effectivescattering/diffraction by Au-NPs/5CB composites leads to a spatial spreading of transmittedcoherent light from a low-power continuous wave laser beam, resulting in a drastic reduction ofits local intensity. The effect is polarization dependent and is strongest when the polarization ofthe input laser beam is along the LTP. The EO response of Au-NPs/5CB mixtures is studiedunder DC and alternating current (AC) joint action with the aim of the potential use of thesecomposite materials as EO controlled diffusers. The specific V-shaped sharp dip in the DCvoltage-dependent coherent light transmittance of Au-NPs/5CB planar films, as well as thepossibility for erasing the scattering/diffractive LTP in the films by joint low AC voltage, can beuseful for EO applications in the field of process control and for detection of weak dynamicelectric fields.
Electro-optically responsive composites of gold nanospheres in 5CB liquid crystal under direct current and alternating current joint action
SCARAMUZZA, Nicola
2014-01-01
Abstract
Direct current (DC) electro-optical (EO) control of transmitted laser beam intensity based on EOcontrolled coherent light scattering and diffraction by stationary longitudinal texture pattern(LTP) is achieved in planar-oriented cells with a composite mixture of polymer-coated goldspherical nanoparticles (Au-NPs) with a mean diameter of about 12 nm and the room-temperaturenematic pentylcyanobiphenyl (5CB). At relatively low DC voltage of about 5 V, the effectivescattering/diffraction by Au-NPs/5CB composites leads to a spatial spreading of transmittedcoherent light from a low-power continuous wave laser beam, resulting in a drastic reduction ofits local intensity. The effect is polarization dependent and is strongest when the polarization ofthe input laser beam is along the LTP. The EO response of Au-NPs/5CB mixtures is studiedunder DC and alternating current (AC) joint action with the aim of the potential use of thesecomposite materials as EO controlled diffusers. The specific V-shaped sharp dip in the DCvoltage-dependent coherent light transmittance of Au-NPs/5CB planar films, as well as thepossibility for erasing the scattering/diffractive LTP in the films by joint low AC voltage, can beuseful for EO applications in the field of process control and for detection of weak dynamicelectric fields.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.