迈克尔逊干涉仪在相位相干成像测量系统中的应用

传统4f相位相干成像测量技术中，利用相位物体使测量材料产生的相位变化转换为可直接观察的振幅变化，实现材料光学非线性折射率的测量。然而相位物体的厚度是固定不变的，相位延迟会随激光波长的改变而改变，测量中需要更换合适的相位物体。理论分析了不同激光波长对相位物体相移大小的影响，详细讨论了不同形状光束下相位物体的半径和相移的大小对4f相位相干成像系统灵敏度的影响。利用了迈克尔逊干涉仪中两束光的相位延迟替代传统相位物体的功能，实现了一种相位可调的相位物体。因为迈克尔逊干涉仪两束光的相位延迟连续可调，使得在不同形状光束及不同波长激光下的测量灵敏度达到最优。该方法进一步完善了4f相位相干成像测量技术，不仅解决了传统相位物体的不足，而且提高了系统测量的精度。

Application of Michelson interferometer in phase coherent imaging measurement system

In the conventional 4f phase coherent imaging measurement technology, phase objects were used to convert the phase change generated by the measured material into a directly observable amplitude change to achieve the measurement of the nonlinear refractive index of the material. However, the thickness of the phase object was fixed, and the phase delay changes with the laser wavelength, and a suitable phase object needs to be replaced in the measurement. The influence of different laser wavelength on the phase shift of the phase object was theoretically analyzed, and the influence of the radius of the phase object and the phase shift on the sensitivity of the 4f phase coherent imaging system was discussed in detail. A phase-adjustable phase object was realized by using the phase delay of two beams in Michelson interferometer instead of the conventional phase object. Because the phase delay of the two beams of Michelson interferometer was continuously adjustable, it makes the sensitivity of measurement at different shapes and different wavelengths of laser optimal. This method further improves the 4f phase coherent imaging measurement technology, not only solves the deficiencies of the conventional phase object, but also improves the accuracy of the measurement.