Wavefront propagation in two-dimensional optical bistable device and its application to maze exploration

: A bistable system with a spatial expanse can support traveling wavefront which is an interface between different stable states such as “on” and “off”. In this work, a two-dimensional thermo-optical bistable device is investigated in terms of wavefront propagation property and its application to maze exploration. It is shown that wavefront velocity is controllable by light intensity and can take even a negative value, i.e. reduction or retreat of the “on”-state area. Utilizing this feature, an application of this device to maze exploration is demonstrated, where extension of the “on” state area explores the whole paths of the maze, and then the device is switched to reduction mode in which the “on” state area retreats from dead-end paths, resulting in the collect path of the maze.