基于数值模拟的高准确度五步相移算法研究

传统五步算法具有很好的准确度,但必须满足测量中无法实现的等步长相移条件,这在实际测量中无法使用。为此在双光束干涉原理的基础上,提出了一种改进型的五步算法,实现了在10 nm范围内任意步长的算法高准确度。通过数值模拟,结果表明:对于1 nm的步长测量误差、0.1%的信号测量误差,改进型五步算法的算法准确度优于0.001个相位周期,而且不需要等步长相移控制。改进型五步算法不仅技术上更易于实现,其结果也更加可靠,对于指导精密测长的实验和研究工作具有十分重要的意义。

Five-Bucket Phase-Shifting Algorithm Based on Numerical Simulation

Although the traditional five-bucket phase-shifting algorithm possesses excellent accuracy,itisn't used in the practical length measurement because of the strict conditions of equal step length of phase shifting.Based on two-beam interference principle,a corrected five-bucket phase-shifting algorithm which possesses high accuracy with an arbitrary phase step in range of 10 nm is present.With the numerical simulation,it shows that the accuracy of the corrected algorithm is better than 0.001 phase period when the measuring error of the phase step is 1 nm and the measuring error of the signal is 0.1%,besides that,this algorithm does not need accurate equal step length of phase shifting.With higher reliability and higher accuracy,the corrected five-bucket phase-shifting algorithm is very valuable for the precision length measurement.