Blue Phase Liquid Crystal for photonic applications beyond display
blue phases (BP) [Fig. 1] of Cholesteric liquid crystals (LC) are liquids that
exhibit orientational order characterized by crystallographic space-group
symmetries. These topologically elegant LC phases possess intriguing optical
properties, which can be tuned electrically, making them a suitable candidate
for photonic applications. BP is thermodynamically stable in a very small
temperature range of 1 - 2 °C. Recently polymer stabilization has been shown to
increase this range to >60 °C (including the room temperature), thus enhancing
their appeal in the research community.
A whole gamut of features of BPLC depends on the platelets size of the domains,
which in turn can be controlled by heating/cooling rates at with which BPs are
prepared. Thus controlling heating/cooling rates become a foremost
technological challenge in the study of BLPC.
Fig. 1 Polarization optical micrographs of BPLC under crossed polarizers
In the purview of this master thesis the student will start with the implementation of algorithms for achieving precise slow heating/cooling rates of 0.01 °C/min. He/she will prepare LC cells using our clean room facility to perform thorough characterization of the same. Various experiments revolving around measurement of effective refractive index as a function of the applied field, reaction time, angular dependence of the optical properties, temperature stability, spectral behavior etc can then be carried out.
Blue phase liquid crystals, Control theory, Electro-optical characterization, clean room.Ardoyen CMST + at home.