New generation photon-counting cameras: algol and CPNG

Abstract

Algol and Comptage de Photons Nouvelle Génération (CPNG) are new generation photon counting cameras developed for high angular resolution in the visible by means of optical aperture synthesis and speckle interferometry and for photon noise limited fast imaging of biological targets. They are intensified CCDs. They have been built to benefit from improvements in photonic commercial components, sensitivity, and personal computer workstations processing power. We present how we achieve optimal performances (sensitivity and spatiotemporal resolution) by the combination of proper optical and electronics design, and real-time elaborated data processing. The number of pixels is 532 x 516 and 1024(2) read at a frame rate of 262 and 100 Hz for CPNG and Algol, respectively. The dark current is very low: 5.5 x 10(-4) e(-) .pixel(-1). s(-1). The saturation flux is approximately 7 photon events /pixel/s. Quantum efficiencies reach up to 36% and 26% in the visible with the GaAsP photocathodes and in the red with the GaAs ones, respectively, thanks to the sensitivity of the photocathodes and to the photon centroiding algorithm; they are likely the highest values reported for intensified CCDs.