Difference-of-Gaussian-Like Characteristics for Optoelectronic Visual Sensor

Architecture using a new nonlinear optoelectronic sensor has been developed to imitate the functions of the higher level visual cortex. The optoelectronic sensor developed in this work has the properties approximated by difference of Gaussian (DOG) functions. The properties are due to the negative photoinduced current (PIC) and the negative differential (ND) characteristics according to the forward bias voltage, which have been successfully obtained for layer structures with a charge-storage layer of InAs/GaAs short-period superlattice. By using the new sensors, an optoelectronic sensing circuit has been designed conceptually to imitate the functions of selectivity to orientation angle, motion-direction and length of slit light in visual cortex.