Fast frequency upconversion imaging based on quasi-phase match

In this paper, a fast frequency upconversion imaging based on quasi-phase match is proposed. A function based on the quasi phase-match of two acquired images within 3dB width is formulated to evaluate the maximum step size of the nonlinear crystal temperature for each acquisition. The measurement time is reduced by acquiring images at these specific temperatures. The integration time of each frame is reassigned to improve the signal noise ratio of the acquired images. Comparing scanning the object with the total measurement time of 44 minutes for a target area with 7mm diameter, our method reaches 12 minutes with just 6 measurements.