Optical time-stretch confocal microscopy at 1 μm

We demonstrate optical time-stretch confocal microscopy in the 1 μm spectral window for high-speed and high-resolution cellular imaging. In contrast to the prior demonstrations of time-stretch imaging, which all operated in the telecommunication band, the present work extends the utility of this imaging modality to a wavelength regime (~1 μm), which is well known to be the optimal diagnostic window in biophotonics. This imaging technique enables us to image the nasopharyngeal epithelial cells with cellular resolution (<2 μm), at a line scan rate of 10 MHz, and with a field of view as wide as ~0.44 mm × 0.1 mm. We also theoretically and experimentally characterized the system performance. As the low-loss dispersive fibers for the time-stretch process as well as other essential optical components for enhancing the imaging sensitivity are commonly available at 1 μm, time-stretch confocal microscopy in this wavelength range could usher in realizing high-speed cell imaging with an unprecedented throughput.