GEORGIA INSTITUTE OF TECHNOLOGY

Under the provisions of the regulations for the degree

MASTER OF SCIENCE

on Tuesday, April 30, 2019

10:00 AM

in MOSE 2100F

will be held the

MASTER’S THESIS DEFENSE

for

Shengtao Yu

“Integration of Optical Structures with Chiral Nanocellulose Films”

Committee Members:

Prof. Vladimir V. Tsukruk, Advisor, MSE

Prof. Zhiqun Lin, MSE

Prof. Wenshan Cai, ECE/MSE

Abstract:

Generation of circular polarized (CP) light via cellulose nanocrystals (CNC) has demonstrated great potential for next generation of chiroptical materials, thanks to the abundance, cost-effective preparation, as well as the retained chiral liquid crystal ordering in solid form.  To enhance the chiroptical properties of CNC film, a convenient strategy capable of integrating both diffractive and refractive optical structures is developed based on top-down lithographic techniques and bottom-up evaporation-induced self-assembly.  The feasibility of such strategy is proved by a few optical structures including photonic gratings, photonic crystals and micro-lenses.  The successful integration of these extrinsic structures with intrinsic chiral structure of CNC is evidenced by preservation of helical stacking structure of CNC as well as a good registration of features size down to sub-micron level with uniformity across large area on the film surface.  As a result, a combination of more accurate and sharper structural color, light focusing capability as well as enhanced circular dichroism is observed, indicating great potential in advanced optical systems based-on CP light.