基于四象限探测器检测干涉条纹正交信号

Detecting orthogonal signals of interference fringes based on four-quadrant detector

四象限探测器在探测区域具有象限化特征,当干涉条纹方向与探测器坐标轴方向呈不同的夹角时,各象限探测单元的不同位置可探测到不同空间位置的干涉条纹光强分布,利用光强在探测单元内的矢量叠加原理,就可探测到与干涉条纹同周期但相位不同的信号。当旋转探测器到某一特定角度时,发现总有其中两个象限探测单元的信号相位正交,当干涉条纹周期改变时,仅需重新仔细旋转探测器,便可检测到该周期条纹的正交信号。通过理论分析和数值模拟,验证了该方法的可行性和实用性。与传统检测方法相比具有操作简便,适应性强,便于仪器化等优点。

If the angle between the orientation of the interference fringes and the detector＇s coordinate axis varies, the four quadrant units may detect different intensity distributions because of their quadrant characteristics, and the intensity of each quad- rant unit may have different phase according to the principle of vector superposition of the cosinusoidal interference fringes. Two detected signals from the four quadrant units, whose phase difference is 90°, could always be found by rotating the detector. When the period of interference fringes changes, the corresponding orthogonal signals by rotating the detector are also detected. Theoretical analysis and numerical simulation validate this method＇s feasibility and practicity. Compared with the traditional method, this method has advantages of simple operation, wide adaptability and easy instrumentation.