Compressive Ultrafast Optical Time-Stretch Imaging

Optical time-stretch imaging is a novel ultrafast imaging technique that is based on space-to-time-to-wavelength mapping and enables ultrafast phenomena to be captured at GHz scan rate. In the conventional high-speed imaging systems, the maximum scan rate is limited by the sampling rate of the digitizer and the temporal dispersion in the fibre to avoid data blending. Therefore the trade-off between high imaging speed and high spatial resolution remains a the bottleneck in these imaging systems. We address these limitations by applying optical encoding on the data that allows the overlapping between the adjacent pulses. The heavily compressed observed data are then reconstructed using the state-of-the-art optimization algorithms under compressive sensing framework. Our results demonstrate that a 10 GHz scan rate can be achieved compared to the conventional 1 GHz microscopy imaging system while maintaining high image reconstruction quality.