Abstract: A method of operating an avalanche photodiode includes providing an avalanche photodiode having a multiplication region capable of amplifying an electric current when subject to an electric field. The multiplication region, in operation, has a first ionization rate for electrons and a second, different, ionization rate for holes. The method also includes applying the electric field to the multiplication region, receiving a current output from the multiplication region, and varying the electric field in time, whereby a portion of the current output is suppressed.

Abstract: A method and apparatus for measuring the duration of a transient signal with high precision.

Abstract: A CMOS image sensor array has rows and columns of active pixels, and column lines in communication with the active pixels in the respective columns. Each active pixel has an output connected to a column line and includes a photodetector that produces a signal proportional to incident light intensity that is coupled to an active pixel output based on column select and row select signals. Each active pixel has a reset transistor for resetting the active pixel, wherein each reset transistor has a first gate terminal and a second gate terminal. The reset transistors have a variable threshold capability that allows increased sensor array dynamic range or mitigation of the effects of temperature or radiation induced transistor threshold voltage shifts. Row select, column select, and sense transistors can also be configured to have variable thresholds.