A fast, high resolution CMOS imager for nanosecond light pulse detections

In this paper, we present design and characterisation of a fast CMOS APS (active pixel sensor) imager for high-speed laser detection, which can replace streak cameras. It produces the intensity information as a function of one spatial dimension and time (I=f (x, t)) from a two spatial dimensions frame. The time information is obtained for the first prototype camera by delaying successively the integration phase for each pixel of the same row. The different noise sources of the APS sensors; such as shot noise due to the photo sensor, thermal noise and flicker noise due to the readout transistors, and the photon shot noise, are presented in order to determine the fundamental limits of the image sensor. The first prototype FAMOSI (fast MOS imager) consists of 64×64 active pixels. The simulation and experimental results show that a conversion gain of 6.73±0.25 μV/e has been obtained with a noise level of 87± 3 electrons rms. The power consumption of the chip is 25 mW at 50 frames/sec. The time resolution is 0.8 ns for this new concept of camera.