Effect of Surface Anchoring on Optical Bistability in Deformed Helix Ferroelectric Liquid Crystal

Prakash, Jai; Choudhary, Amit; Mehta, Dalip Singh; Biradar, A. M.

doi:10.1080/15421400903053768

Cited by 5 publications

(5 citation statements)

References 31 publications

(30 reference statements)

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“…The memory effect observed in these DHFLC cells is static, and stays in a stable state for a longer duration (hours) contrary to earlier observed memory, which was transient. Apart from the memory effect observed in unanchored DHFLC cells, we also proposed and observed that an ultra weak surface anchoring leads to a lower satur ation voltage and steepness in the electro-optical properties of FLCs [77,78].…”

Section: Memory Effect In Flcsmentioning

confidence: 77%

“…The memory effect observed in NLC and SSFLC was not long lasting, but a transient one. The bistability (memory) in deformed-helix ferroelectric liquid crystals (DHFLC) has been investigated by various groups, including ours, through dielectric, electro-optical, and other methods [69][70][71][72][73][74][75][76][77][78][79]. The memory in DHFLC materials is not similar to the conventional memory effect of FLC materials due to surface stabilization because the pitch value is in the submicron range.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Scientific developments of liquid crystal-based optical memory: a review

2016

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The memory behavior in liquid crystals (LCs), although rarely observed, has made very significant headway over the past three decades since their discovery in nematic type LCs. It has gone from a mere scientific curiosity to application in variety of commodities. The memory element formed by numerous LCs have been protected by patents, and some commercialized, and used as compensation to non-volatile memory devices, and as memory in personal computers and digital cameras. They also have the low cost, large area, high speed, and high density memory needed for advanced computers and digital electronics. Short and long duration memory behavior for industrial applications have been obtained from several LC materials, and an LC memory with interesting features and applications has been demonstrated using numerous LCs. However, considerable challenges still exist in searching for highly efficient, stable, and long-lifespan materials and methods so that the development of useful memory devices is possible. This review focuses on the scientific and technological approach of fascinating applications of LC-based memory. We address the introduction, development status, novel design and engineering principles, and parameters of LC memory. We also address how the amalgamation of LCs could bring significant change/improvement in memory effects in the emerging field of nanotechnology, and the application of LC memory as the active component for futuristic and interesting memory devices.

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Section: Memory Effect In Flcsmentioning

confidence: 77%

Section: Introductionmentioning

confidence: 99%

Scientific developments of liquid crystal-based optical memory: a review

2016

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“…The similar behaviour of P S with cell thickness in DHFLCs has also been reported. [9,25] The decrease in P S in case of thicker cells is due to poor alignment of cells. Due to poor alignment of thicker cells, the dipoles are randomly oriented and P S decreases.…”

Section: Resultsmentioning

confidence: 98%

Role of cell thickness in tailoring the dielectric and electro-optical parameters of ferroelectric liquid crystals

et al. 2015

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Here, we report thickness dependence of dielectric and electro-optical parameters in ferroelectric liquid crystals (FLCs) without surface stabilisation. The dependence of dielectric and electro-optical parameters on cell thickness is observed by dielectric spectroscopy and electro-optical measurements. The dielectric permittivity (ε 0 ) measured by varying the cell thickness showed increase of ε 0 with increase of cell thickness which is attributed to the presence of more ions and larger contributions of Goldstone mode in thick cells. The spontaneous polarisation also shows increment with increase of cell gap up to certain thickness range. The rotational viscosity decreases with increase in the cell thickness whereas the response time is more for thicker cells. The decrease in the rotational viscosity is attributed to lowering of elastic deformation with increase in cell thickness and the response time is directly proportional to cell gap. These studies would be utilised to understand the effect of cell thickness on dielectric and electro-optical properties of FLC materials and optimising the material parameters with cell thickness for better and efficient liquid-crystal-based devices.

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“…While the TGB phases, being the LC analogues of the Abrikosov phases, have attracted intense scientific interest, the BPs hold potential for next-generation display and photonics device applications; consequently, there have been some successful attempts lately to widen the thermal range of such phases. − On the other hand, the N* and SmC* phases are the classical examples of defect-free helical LC structures exhibiting a wide range of unique and fascinating phenomenon. For example, the N* phase shows temperature-dependent selective reflection (thermochromism), and thus, it is used in thermochromic devices. ,,, The SmC* phase shows ferroelectric switching, which is being well-used in realizing advanced display devices featuring high image quality, high resolution, wide-viewing angles, and fast response time. ,,− In essence, chiral LCs exhibit a dizzying array of special properties and structures that have great significance in the fields of both fundamental research and applied science.…”

Section: Introductionmentioning

confidence: 99%

“…In view of such a marked thermal behavior of chiral LCs, the authors have been engaged for more than a decade in the rational design, synthesis, and characterization of a vast array of optically active LCs, − including polymers . The experimental results of these investigations have clearly demonstrated the inherent capability of such chiral LCs in stabilizing a variety of novel phase sequences and frustrated/technologically important LC phases over a wide thermal range.…”

Section: Introductionmentioning

confidence: 99%

Stable Ferroelectric Liquid Crystals Derived from Salicylaldimine-Core

2015

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Five pairs of enantiomers derived from salicylaldimine-core have been prepared by condensing (R)- or (S)-4-(octan-2-yloxy)anilines with 4-formyl-3-hydroxyphenyl 4-(n-alkoxy)benzoates. They have been designed to probe the correlation between molecular structure and mesomorphism, and especially to provide stable mesogens having potential for applications in ferroelectric liquid crystal devices. Thus, they have been substituted with a chiral tail at one end and by n-alkoxy chains of varying length at the other terminal. A detailed study confirms an indistinguishable behavior of all ten mesogens exhibiting an enantiotropic chiral smectic C (SmC*) phase besides blue phase (BP) and chiral nematic (N*) phase. The SmC* phase occurring over a 50-70 °C thermal width shows ferroelectric switching with spontaneous polarization (Ps) value crossing over 100 nC/cm(2). Circular dichroism spectroscopic study of the mesophases confirms the chromophores of the molecules being in the macroscopic chiral (helical) environment.

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Effect of Surface Anchoring on Optical Bistability in Deformed Helix Ferroelectric Liquid Crystal

Cited by 5 publications

References 31 publications

Scientific developments of liquid crystal-based optical memory: a review

Scientific developments of liquid crystal-based optical memory: a review

Role of cell thickness in tailoring the dielectric and electro-optical parameters of ferroelectric liquid crystals

Stable Ferroelectric Liquid Crystals Derived from Salicylaldimine-Core

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