在关联成像中，赝热光源的特性对成像质量至关重要。赝热光源的关联特性和关联成像的对比度、信噪比和分辨率密切相关。在其他条件相同的情况下，二阶关联峰值越高，所成关联像的对比度越高，而赝热光源的随机性越好，则成像的信噪比越高。赝热光源的产生有很多方案，近来出现的基于空间光调制器的赝热光源由于其相位可预置性而具有很好的应用前景。本文介绍了利用空间光调制器调相、调幅等不同调制方法产生赝热光源的原理，并通过模拟对比了施加不同的振幅、相位及其混合调制所引起的赝热光源的二阶关联峰值的差异性，对比发现当振幅分布为瑞利分布、相位分布为0～2π 均匀分布时，赝热光关联峰值理论可以达到2，此时赝热光源的特性较为理想。

The characteristics of correlation for pseudo-thermal light source have much effect on the quality of image in ghost imaging. The correlated characteristics of pseudo-thermal light have relations with contrast, signal to noise ratio and resolution. On the same condition of experiment, the higher the peak value of the twoorder correlation, the higher the contrast of the image, and the better for the randomness of the pseudo-thermal light, the higher for the signal to noise ratio of the image. Recently, varieties of schemes for correlated imaging have emerged, and pseudo-thermal light correlated imaging based on space light modulator（SLM） has good prospect. The theory of pseudo-thermal light based on different modulation is presented, by which we have simulated the two-order correlation of pseudo-thermal light when different modulations have been sent to SLM, and a conclusion has come that when SLM is modulated by the mixture of phase and amplitude, the peak value of the two-order correlation is the highest, especially when the probability distribution for amplitude is Rayleigh distribution and the phase is evenly distributed between 0~2p, and the peak value of the two-order correlation can come to 2, and the characteristic of pseudo-thermal light is ideal.