  Fast, volumetric imaging over large scales has been a long-standing goal in
biological microscopy. Scanning techniques such as fluorescence confocal
microscopy can acquire 2D images at high resolution and high speed, but
extending the acquisition to multiple planes at different depths requires an
axial scanning mechanism that drastically reduces the acquisition speed. To
address this challenge, we report an augmented variant of confocal microscopy
where the key innovation consists to use a series of reflecting pinholes
axially distributed in the detection plane, each one probing a different depth
within the sample. As no axial scanning mechanism is involved, our technique
provides simultaneous multiplane imaging over fields of view larger than a
millimeter at video-rate. We demonstrate the general applicability of our
technique to neuronal imaging of both Caenorhabditis elegans and mouse brains
in-vivo.
