Fluorescence flutter shutter

Fluorescence imaging is challenging on cells in motion because the exposure time is constrained by motion blur. The maximum number of photons that can be collected in a given time interval is fundamentally limited by the fluorophore's excited state lifetime, so methods to increase the effective exposure time are needed.

While it is not possible to deconvolve the motion blur from a typical long exposure, it is possible when the exposure is modulated by a pseudo-random code.  By temporally modulating the fluorescence excitation, we have shown that it is possible to obtain a 50 times longer exposure time and yet still obtain near diffraction-limited resolution.

Sai Siva Gorthi, Diane Schaak, and Ethan Schonbrun, "Fluorescence imaging of flowing cells using a temporally coded excitation," Opt. Exp. 21, 5164-5170 (2013).