Fluorescence lifetime imaging in an optically sectioning programmable array microscope (PAM). 
The programmable array microscopes (PAMs) are a family of instruments incorporating arbitrary control of the patterns of illumination and/or detection.  The PAM can be used in sectioning and nonsectioning modes, thereby constituting a useful platform for fluorescence lifetime imaging.  We used a PAM for acquisition of optically sectioned and widefield fluorescence lifetime images, in which contrast was increased predominantly by suppressing out-of-focus light contributions.  We simulate, display, and discuss the effects of blurring and fluorophore heterogeneity on lifetime imaging in widefield and confocal configurations.  Sectioning improves the quality of lifetime images of samples with multiple fluorophores or spatially varying Förster resonance energy transfer.