High-speed Imaging of Spatiotemporal Liquid Crystal Switching Dynamics.
Jin, Yang.
2015
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Abstract: Liquid
crystals (LCs) are widely used for light modulation in industrial and commercial
applications including device display technologies and optical switches for
telecommunications. The elongation of LC molecules and their alignment to applied
electric fields confers their unique electro-optical properties. However, their temporal
response or `switching speed' due to an applied ... read moreelectric field is the primary limitation
governing the overall performance of LC devices. To engineer better LC materials and
faster devices, detailed knowledge of complex electrodynamic phenomena in LCs is
required, yet no diagnostic methods are currently available to characterize fast
temporal dynamics with high spatial resolution. In an effort to mediate this gap between
instrumentation and LC physics, we have developed a technique based on high-speed
imaging and polarization microscopy, which is used to characterize the spatiotemporal
dynamics of LC switching on millisecond time scales with micron spatial resolution. To
demonstrate the efficacy of this high-speed imaging method, we characterize the
switching time scale for a standard Freedericksz cell as a function of the applied
voltage. As a second industrially-relevant LC device geometry, we microfabricated an
in-plane switching device that generates a highly non-uniform electric field, enabling
us to measure spatial variations in switching speed within a single micro-scale device.
Experimental results were compared with theoretical models to benchmark results, and
also to quantitatively determine the LC switching dynamics from processed digital
high-speed videos.
Thesis (M.S.)--Tufts University, 2015.
Submitted to the Dept. of Mechanical Engineering.
Advisor: Jeffrey Guasto.
Committee: Behrouz Abedian, and Timothy Atherton.
Keywords: Materials Science, and Engineering.read less - ID:
- kd17d435g
- Component ID:
- tufts:21470
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- TARC Citation Guide EndNote