Time Multiplexed Spectrally Encoded Imaging (SEI)

The spectrally encoded imaging (SEI) diagnostic enables streak camera capabilities through a single optical fiber. This feature allows for remote fielding on dynamic experiments lacking direct optical access. The real-time system also runs continuously with unlimited trigger variability, allowing for post-event triggering when necessary. Using compact fiber-based femtosecond laser sources, broadband light within the optimal C-band is generated to drive each imaging channel. With enough sources and sufficient power, multiple imaging channels can be simultaneously fielded on a single experiment. The general limitation on unlimited expansion stems from the real-time digitizer, which is costly and channel limited. To alleviate this issue, time multiplexing techniques are used to maximize existing digitizer capabilities. By splitting power from our four-channel light source, we are currently able to support eight optical probes directed at different locations along the target. Return signal pulses from four of the channels are delayed and recompressed with specialized fiber before being optically switched onto the same digitizer channels used by the other four channels at an earlier time. Via this technique, we are able to simultaneously field eight imaging channels on our dynamic experiments, which is equivalent to fielding eight independent streak cameras on a single dynamic shot.