uri physics colloquium

Interface States in One Dimensional Binary/Quaternary Photonic Crystal Heterostructures

Nicholas Bianchi

URI  Physics Department

Friday, March 20, 2020

4 pm, East Hall Room 112

abstract

The existence of topological interface states is investigated in a heterostructure consisting of a binary photonic crystal and a quaternary photonic crystal. The individual crystals possess inversion symmetric unit cells. In this work, a photonic crystal is made quaternary by inserting a tunable third layer into two different locations in the unit cell. Conditions are established that describe where the quaternary crystal can exist in parameter space subject to constraints. The closing of band gaps is discussed for different optical path ratios. When the binary and quaternary crystals share an interface, optical states appear at the interface when the two crystals have different signs for the surface impedance. The evolution of the states is displayed as the geometry of the quaternary crystal changes.