Gerberding Oliver, Isleif Katharina-Sophie
Institute of Experimental Physics, University of Hamburg, Luruper Chaussee 149, D-22761 Hamburg, Germany.
Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, D-22607 Hamburg, Germany.
Sensors (Basel). 2021 Mar 2;21(5):1708. doi: 10.3390/s21051708.
We present a compact optical head design for wide-range and low noise displacement sensing using deep frequency modulation interferometry (DFMI). The on-axis beam topology is realised in a quasi-monolithic component and relies on cube beamsplitters and beam transmission through perpendicular surfaces to keep angular alignment constant when operating in air or in a vacuum, which leads to the generation of ghost beams that can limit the phase readout linearity. We investigated the coupling of these beams into the non-linear phase readout scheme of DFMI and implemented adjustments of the phase estimation algorithm to reduce this effect. This was done through a combination of balanced detection and the inherent orthogonality of beat signals with different relative time-delays in deep frequency modulation interferometry, which is a unique feature not available for heterodyne, quadrature or homodyne interferometry.
我们展示了一种紧凑的光学头设计，用于采用深度频率调制干涉测量法（DFMI）的大范围、低噪声位移传感。轴上光束拓扑结构在一个准单片组件中实现，依赖于立方分束器以及光束通过垂直表面的传输，以便在空气中或真空中操作时保持角度对准恒定，这会导致产生可能限制相位读出线性度的鬼光束。我们研究了这些光束与DFMI的非线性相位读出方案的耦合，并实施了相位估计算法的调整以减少这种影响。这是通过深度频率调制干涉测量法中平衡检测与具有不同相对时间延迟的拍频信号的固有正交性相结合来实现的，这是外差、正交或零差干涉测量法所不具备的独特特性。
