Abstract
We review the technique of 2-dimensional spatiotemporal focusing (2D STF). STF employs ultrashort
lasers pulses, which are spatially chirped by a diffractive grating, to generate the Fourier-transform-limited
pulse only at a focal plane. STF offers a widefield illumination feature in two-photon excited fluorescence
microscopy. 2D STF inherits this idea but uses a 2D spectral disperser to further stretch the
out-of-focus pulse in spatiotemporal domain. By giving a simple mathematical analysis, we show the
improved sectioning ability of 2D STF compared with STF. 2D STF based two-photon excitation fluorescence
microscopy can realize fast volume imaging. An example to trace the 3-dimensional Brownie
motion is demonstrated.
