scholarly journals Electrically tuned whispering gallery modes microresonator based on microstructured optical fibers infiltrated with dual-frequency liquid crystals

Nanophotonics ◽  
2018 ◽  
Vol 7 (7) ◽  
pp. 1333-1340 ◽  
Author(s):  
Chengkun Yang ◽  
Hao Zhang ◽  
Bo Liu ◽  
Haifeng Liu ◽  
Chao Wang ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Electric Field ◽  
Optical Fibers ◽  
Applied Electric Field ◽  
Optical Switching ◽  
Resonance Wavelength ◽  
Crossover Frequency ◽  
Dual Frequency ◽  
Whispering Gallery ◽  
Operation Frequency

AbstractAn electrically tunable whispering gallery mode (WGM) microresonator based on an HF-etched microstructured optical fiber (MOF) infiltrated with dual-frequency liquid crystals (DFLCs) is proposed and experimentally demonstrated for the investigation of the crossover frequency and Freedericksz transition of DFLCs. Experimental results indicate that for applied electric field with operation frequency below the crossover frequency, WGM resonance wavelength decreases with the increment of applied electric field strength. On the contrary, for applied electric field with operation frequency beyond the crossover frequency, WGM resonance dips show red shift as the applied electric field intensity increases. The proposed electrically tunable microcavity integrated with DFLCs is anticipated to find potential applications in optical filtering, all-optical switching, and electrically manipulated bi-directional micro-optics devices.

scholarly journals Evaluation of 4-alkoxy-4′-nitrobiphenyl liquid crystals for use in next generation scattering LCDs

RSC Advances ◽  
2017 ◽  
Vol 7 (64) ◽  
pp. 40480-40485 ◽  
Author(s):  
Richard J. Mandle ◽  
Stephen J. Cowling ◽  
John W. Goodby
Keyword(s):  
Liquid Crystals ◽  
Electric Field ◽  
Applied Electric Field ◽  
Field Studies ◽  
Next Generation ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

A combination of microscopy, X-ray scattering, calorimetry and applied electric field studies demonstrates the 4-alkoxy-4′-nitrobiphenyls are potentially of use for next generation, backlight free scattering mode LCD devices.

Nano-Sized Fine Droplets of Liquid Crystals for Optical Application

1996 ◽  
Vol 457 ◽  
Author(s):  
Shiro Matsumoto ◽  
Marthe Houlbert ◽  
Takayoshi Hayashi ◽  
Ken-ichi Kubodera
Keyword(s):  
Liquid Crystal ◽  
Phase Separation ◽  
Liquid Crystals ◽  
Electric Field ◽  
Applied Voltage ◽  
Applied Electric Field ◽  
Uv Curing ◽  
Infrared Region ◽  
High Transparency ◽  
Power Change

ABSTRACTNano-sized fine droplets of liquid crystal (LC) were obtained by phase separation of nematic LC in UV curing polymer. The polymer composite had a high transparency in the infrared region. The fine droplets responded to an electric field causing a change in birefringence. Output power change was brought about by the generated retardation between two polarizations, parallel and perpendicular to the applied electric field. This differs from the composite containing much larger droplets, where output depends on the degree of scattering. The birefringence changed by 0.001 at the applied voltage of 7.5 V/μm.

The breathers in nematic liquid crystals under applied electric field

2019 ◽  
Vol 33 (26) ◽  
pp. 1950319
Author(s):  
Yan Li ◽  
Xiaobo Lu ◽  
Chunfeng Hou
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Electric Field ◽  
Nematic Liquid Crystal ◽  
Dynamic Equation ◽  
Applied Electric Field ◽  
Deflection Angle ◽  
Breather Solution ◽  
The Relationship ◽  
Sg Equation

In this paper, we study the twist of the nematic liquid crystal molecules under the applied electric field. The dynamic equation of the twisted molecules is derived. It is proved to be a kind of sine-Gordon (SG) equation. We obtain the breather solution of the equation and confirm that the deflection angles of the twisted molecules can distribute in the form of breathers. We give the relationship between the molecular deflection angle and the breather frequency, and discuss the effect of electric field on breather shape and breather frequency.

scholarly journals Mathematical Model for Electric Field Sensor Based on Whispering Gallery Modes Using Navier’s Equation for Linear Elasticity

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Amir R. Ali ◽  
Mohamed A. Kamel
Keyword(s):  
Mathematical Model ◽  
Electric Field ◽  
Linear Elasticity ◽  
Transmission Spectrum ◽  
Applied Electric Field ◽  
Sensing Element ◽  
Optical Resonance ◽  
Whispering Gallery ◽  
Electric Field Sensor ◽  
Optical Modes

This paper presents and verifies the mathematical model of an electric field senor based on the whispering gallery mode (WGM). The sensing element is a dielectric microsphere, where the light is used to tune the optical modes of the microsphere. The light undergoes total internal reflection along the circumference of the sphere; then it experiences optical resonance. The WGM are monitored as sharp dips on the transmission spectrum. These modes are very sensitive to morphology changes of the sphere, such that, for every minute change in the sphere’s morphology, a shift in the transmission spectrum will happen and that is known as WGM shifts. Due to the electrostriction effect, the applied electric field will induce forces acting on the surface of the dielectric sphere. In turn, these forces will deform the sphere causing shifts in its WGM spectrum. The applied electric field can be obtained by calculating these shifts. Navier’s equation for linear elasticity is used to model the deformation of the sphere to find the WGM shift. The finite element numerical studies are performed to verify the introduced model and to study the behavior of the sensor at different values of microspheres’ Young’s modulus and dielectric constant. Furthermore, the sensitivity and resolution of the developed WGM electric filed sensor model will be presented in this paper.

Effects of applied electric field on orientational photorefraction in porphyrin:Zn-doped nematic liquid crystals

2004 ◽  
Vol 85 (3) ◽  
pp. 366-368 ◽  
Author(s):  
Ki Hyun Kim ◽  
Eun Ju Kim ◽  
Sang Jo Lee ◽  
Jung Hoon Lee ◽  
Chong Hoon Kwak ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Electric Field ◽  
Applied Electric Field ◽  
Nematic Liquid Crystals

Microsecond Time-Resolved Infrared Study of the Electric-Field-Induced Reorientation of Nematic Liquid Crystals. Part II: Dependence of the Motion of Liquid Crystals on the Applied Electric Field

1993 ◽  
Vol 47 (12) ◽  
pp. 2108-2113 ◽  
Author(s):  
Taeko I. Urano ◽  
Hiro-O Hamaguchi
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Electric Field ◽  
Applied Electric Field ◽  
Slow Component ◽  
Fast Component ◽  
Rigid Core ◽  
Time Resolved ◽  
Flexible Part ◽  
Reorientation Motion

The electric-field dependence of the reorientation motion of a nematic liquid crystal, 5CB (4- n-pentyl-4'-cyanobiphenyl), has been studied by microsecond time-resolved infrared spectroscopy. A rectangular pulsed electric field with a short pulse duration (2 ms) and a low repetition rate (5 Hz) was used to examine the liquid crystal (LC) response in a silicon cell. The motion of the rigid core part (the cyanobiphenyl group) of 5CB was monitored by the CN stretch band and that of the flexible part (the pentyl group) by the pentyl CH stretch band. The response of the LC to the pulsed electric field consists of two components, the slow component and the fast component. The slow component is common to the rigid core and the flexible parts of SCB. The voltage dependence of the slow component exhibits a clear threshold, indicating that this component corresponds to a cooperative motion of the 5CB molecules. The fast component is specific to the flexible part and shows exponential rise and decay behavior patterns. This observation suggests that the fast component corresponds to some noncooperative motions which are characteristic of the pentyl group. It is most likely that the internal rotation around the C(biphenyl)-C(pentyl) bond is responsible for the fast component. It is suggested that the LC molecules near the cell interface play a key role in the primary stage of the reorientation motion under an applied electric field.

Dielectrophoretic Manipulation of Polystyrene Micro Particles in Microfluidic Systems

2009 ◽  
Author(s):  
C. Zhang ◽  
K. Khoshmanesh ◽  
A. A. Kayani ◽  
F. J. Tovar-Lopez ◽  
W. Wlodarski ◽  
...  
Keyword(s):  
Electric Field ◽  
Liquid Flow ◽  
Applied Electric Field ◽  
Theoretical Calculations ◽  
Optimum Operating ◽  
Crossover Frequency ◽  
Flow Rates ◽  
Micro Particles ◽  
Wide Range ◽  
Pdms Microchannel

In this work, DEP platforms with funnelled and micro-tip electrode patterns were fabricated, and integrated with polydimethylsiloxane (PDMS) microchannel blocks. The DEP platforms were employed to manipulate polystyrene particles of 1 and 3 μm. The response of the system was characterised in a wide range of signal magnitudes (1–30 V peak-to-peak) and frequencies (100 kHz to 200 MHz), as well as the liquid flow rates (1 to 10 μL/min). Calculations were also carried out to analyse the DEP spectra of polystyrene particles when suspended in the medium (deionised water) to determine the optimum operating frequency of the DEP systems. Both experimental results and theoretical calculations indicated that polystyrene particles can experience positive and negative DEP forces within certain frequency ranges of the applied electric field, and the crossover frequency (where the DEP force is zero) of the system strongly depends on the conductivities of the particles. Additionally, larger particles experience stronger DEP forces and can be more efficiently concentrated at or repelled along the electrodes. The concentration performance of the DEP systems were evaluated by measuring the thickness of particle streams at different flow rates. Finally, the ability of funnelled and micro-tip electrodes to trap the particles was compared.

scholarly journals Electro-Optical Switching of Dual-Frequency Nematic Liquid Crystals: Regimes of Thin and Thick Cells

Crystals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 314 ◽  
Author(s):  
Olha Melnyk ◽  
Yuriy Garbovskiy ◽  
Dario Bueno-Baques ◽  
Anatoliy Glushchenko
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Optical Switching ◽  
Nematic Liquid Crystals ◽  
Optical Response ◽  
Thin Layers ◽  
Optical Performance ◽  
Dual Frequency ◽  
Crystal Cells ◽  
Cell Thickness

Conventional display applications of liquid crystals utilize thin layers of mesogenic materials, typically less than 10 µm. However, emerging non-display applications will require thicker, i.e., greater than 100 µm, layers of liquid crystals. Although electro-optical performance of relatively thin liquid crystal cells is well-documented, little is known about the properties of thicker liquid crystal layers. In this paper, the electro-optical response of dual-frequency nematic liquid crystals is studied using a broad range (2–200 µm) of the cell thickness. Two regimes of electro-optical switching of dual-frequency nematics are observed and analyzed.

scholarly journals Annihilation dynamics of topological defects induced by microparticles in nematic liquid crystals

Soft Matter ◽  
2019 ◽  
Vol 15 (43) ◽  
pp. 8749-8757 ◽  
Author(s):  
Yuan Shen ◽  
Ingo Dierking
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Electric Field ◽  
Applied Electric Field ◽  
Topological Defects ◽  
Field Conditions ◽  
Viscous Drag ◽  
Complex Interplay ◽  
Drag Forces ◽  
Micro Particles

The annihilation dynamics of liquid crystal topological defects with micro-particles is governed by a complex interplay between elastic attraction, backflow, viscous drag forces, confinement and applied electric field conditions.

Sign in / Sign up

Export Citation Format

Share Document