Coherent Laser Source for High Frame-Rate Optical Time-Stretch Microscopy at 1.0 μm

• Published in: IEEE journal of selected topics in quantum electronics 2014-09, Vol.20 (5), p.384-389
• Main Authors: Xiaoming Wei, Lau, Andy K. S., Wong, Terence T. W., Chi Zhang, Tsia, Kevin K. M., Wong, Kenneth K. Y.
• Format: Article
• Language: English
• Subjects: Coherence; Degradation; Fiber lasers; Frames; Imaging; Laser mode locking; Medical and biological imaging; Microscopy; Optical fiber dispersion; Optical fibers; Optical pulses; Pulsed lasers; Real-time systems; supercontinuum generation; Trains; ultrafast technology; ytterbium mode-locked laser
• ISSN: 1077-260X; 1558-4542
• DOI: 10.1109/JSTQE.2014.2302536

We demonstrate a coherent picosecond pulsed fiber laser for the high frame-rate optical time-stretch microscopy at 1.0 μm. The spectrum of a picosecond pulsed laser is commonly broadened before the time-stretch imaging, which however will degrade its stability and coherence. As a result, it is required to enhance the degraded signal-to-noise ratio by averaging, which would compromise the frame rate on the other hand. Instead of pursuing such kind of spectrum-broadened picosecond pulsed laser sources, we propose a pulse train extracted directly from an all-normal dispersion mode-locked fiber laser with a rectangle-shaped optical spectrum. It delivers stable and coherent performance for the serial time-encoded amplified microscopy at 1.0 μm. With this robust picosecond pulsed laser, real-time stain-free flow imaging with a frame rate of 26.25 MHz and a spatial resolution of