Ultrafast, laser-scanning time-stretch microscopy with visible light

We demonstrate ultrafast time-stretch microscopy in, to the best of our knowledge, the shortest wavelength regimes, i.e. 532 nm. This is enabled by a new all-optical ultrahigh-speed laser-scanning technique called free-space angular-chirpenhanced delay (FACED) that achieves a line-scan rate as high as 20 MHz. In contrast to the predominant fiber-based implementation, time-stretch imaging based on FACED allows wavelength-independent and low-loss operations, and more intriguingly reconfigurable all-optical laser-scanning rate. Using this technique, we present high-resolution single-cell images captured in an ultrafast microfluidic flow (1.5m/s). This could unleash numerous cell and tissue imaging applications, e.g. high-throughput image flow cytometry and whole-slide imaging.