Interference Fringe Analysis for Precision Measurement by Using Conoscopic Interferometer

In this paper, we propose a novel fringe phase analysis method that can quickly and accurately perform the interference fringe analysis for precise measurement by using a conoscopic interferometer. In general, interference fringe phase analysis is an important issue for the measurement using laser interference. Although many studies have been carried out on the conoscopic interferometer and its applications, no full-scale study has been carried out on the problem of the phase analysis of the interference fringes and shortening the time in the precision measurement using the conoscopic interferometer. This problem can be solved by an efficient fringe analysis method. In the conoscopic interferometer, the precision measurement was performed by measuring the change in the number of fringes due to the change in distance. This method has low accuracy and slow measurement speed. In this paper, we propose a novel method to quickly analyze the phase of the conoscopic interference fringe by means of the determination of the extremum points and briefly discuss the interference fringe filtering. Since the interference pattern obtained in the conoscopic interferometer is related to the distance, the analysis of the interference pattern gives the distance. The interference pattern can be simply analyzed since the phase difference between two adjacent extrema is 2π. The proposed method allows a simple and rapid analysis of the interferogram of the conoscopic interferometer, thus increasing the accuracy and speed of precision measurements using the conoscopic interferometer. The proposed fringe analysis method can be used not only for the analysis of the conoscopic interference fringe but also for other sorts of fringe analysis.