光强不均匀情况下曲率波前传感器的信号分析

Signal Analysis of Wavefront Curvature Sensor Under Nonuniform Intensity

曲率波前传感器广泛应用于天文自适应光学、光学度量等领域。在这些领域使用时都假设入射波前光强均匀,但这种假设与曲率传感技术的基本原理不一致。定性分析了曲率波前传感技术理论的不自洽,利用衍射理论和几何光学近似的方法,推导了光强不均匀情况下曲率波前传感器信号的解析式,分析了信号误差。结果表明,光强不均匀情况下曲率波前传感器的信号引入了光强对数的梯度和波前梯度的点乘项。在大多数应用中,点乘项可以忽略,因此,光强均匀的假设是合理的。但应用于光强量级发生变化的激光高斯光束时,会有一定的误差。

Wavefront curvature sensor has been applied in the fields of adaptive optics and optical metrology. It is assumed that the intensity of the incident wavefront is uniform in these fields, but this assumption is not in accord with the principle of the curvature sensing technology. The theory self-contradiction of the wavefront curvature sensing technology is analyzed qualitatively in this paper. By means of the diffraction theory and geometrical optics approximation, the signal expression of wavefront curvature sensing under nonuniform intensity is deduced, and the signal error is analyzed as well. The results show that nonuniform intensity introduces the dot product of intensity logarithm and wavefront gradient. Under most conditions, the dot product can be ignored, so the assumption of the uniform intensity is rational. But in the laser Gaussian beam whose intensity magnitude changes, error occurs.