Real-time edge-enhanced optical correlation via four-wave mixing in a cerium doped potassium sodium strontium barium niobate crystal

摘要

Degenerate four-wave mixing in a cerium doped potassium sodium strontium barium niobate photorefractive crystal is studied. The transmission grating is dominated in our experimental geometry that the bisecotr of the pump beam and the signal beam is novmal to the c-axis of the crystal. As the fringe modulation depth of this transmission grating varies, the variation of the conjugated beam intensity forms a loop. Based on this nonlinear property, real-time optical image edge-enhancemnet processing as well as real-time edge-enhanced optical correaltion is obtianed without the reverse of the signal-to-pump beam intensity ratio. The Full-Width-at-Half-Maximum intensity of the auto-correlation peak is one fifth of that without the edge-enhancement operation. The computer simulation results are given, which are coincident with the experimental data very well.