Parametric Amplification Characteristics of Weak Image
微弱光学图像的光参量放大特性的研究

The image amplification characteristics in optical parametric image amplification are investigated.The phase-match condition,the spatial frequency bandwidth of crystal and the image signal gain are simulated.The numerical simulation results are validated in optical parametric image amplification experiment with BBO (b-BaB2O4) type-I crystal.Theoretical and experimental results show that when the spatial frequency bandwidth of crystal than the band of the input image signal and the perfectly phase match,the weak optical image are amplified without distortion.The gain peak shifts to higher spatial frequencies and spatial bandwidth narrows,this effect occurs when a small phase mismatch is induced.As the magnitude of this mismatch is increased,optical parametric image amplification could be used to selectively amplify the given spatial-frequency of the weak image.