The Fundamental Research Of Serial Time-Encoded Dynamic Imaging System

In this paper, the key technique of serial time-encoded amplified dynamic imaging system, optical time-stretch and Raman pump amplification, has been carried on the detailed theoretical and experimental research. The function of time span with different dispersion parameter and dispersion slope has been analyzed, and the effect of dispersion parameters and dispersion slope on spectral resolution was discussed. The gain factor of collected signal can be up to 20.53 dB by distributed Raman amplification under optimal signal-to-noise conditions. By measuring the signal-to-noise ratio, we also found the optimal signal-to-noise ratio of with proper forward and backward pump power, and put forward a solution used for searching the optimal signal-to-noise.We also proposed relative solutions for improving space to fiber coupling efficiency, adjusting optical axis position, and alleviating divergence angle disagreement in the experimental light path. The restricted relationship of different parts of the system was discussed in detail. Three different imaging systems were compared to optimize the transmission efficiency. A 25 MHZ repetition rate line-scanning ultrafast imaging system was set up, some parts like laser modules and sampling system are simplified to reduce cost. Total resolution of the system, which is used for comparing with the theoretical value, was estimated at last.A new imaging method for serial time-encoded amplified microscopy is proposed, which eliminates the impact of spectrum ripples in the non-flat spectrum source and non-uniform gain. This method can also avoid the waste of low-level amplitude in the pulse edge. A related VBA program was written, and data were collected for the off-line processing. At last, a clear image of first-group of USAF-1951 resolution board was reconstructed with 60μm vertical resolution and 42μm horizontal resolution. My research provided many technique details and ideas for developing the microminiaturization, real-time display and more frequency band of the serial time-encoded amplified dynamic imaging system in the future.