为瞬态测量近红外激光波前,提出了一种斜入射结构的反射式错位点衍射干涉仪方案。将点衍射干涉仪集成在镀有特殊膜系的平板基片上,相干光波分别在平板前后表面反射产生错位,从而在传统点衍射干涉图中引入空间线性载频。采用傅里叶变换的方法处理单幅干涉图恢复待测波前,实现了近红外波前的自动化检测。实验测量了F/10、工作波长为1313 nm的近红外激光波前,测量结果与Hartmann波前传感器一致。研究了用于针孔快速对准的成像对准技术。因此,采用该方案能够实现近红外波前的瞬态测量。
In order to measure the dynamic near infrared laser wavefront, a structure of oblique incidence of reflective shearing point diffraction interferometer is proposed. The point diffraction interferometer is integrated in flat substrate plated with special films. The coherent beams are reflected at the front and rear surfaces of the substrate respectively. The shear of the two beams introduces linear spatial carrier frequency to the point diffraction interferogram. The single shot interferogram is processed by Fourier transform method to retrieve the near infrared wavefront under test automatically. Experiment is carried on to test the transmitted wavefront of a F/10 lenses 1 313 nm wavelength and the result is in agreement with that obtained by Hartmann wavefront sensor. Image alignment method is studied that is used for quick pinhole alignment. As a result, the project can be applied to measure the dynamic near infrared wavefront.