Proceedings Article | 26 June 2017
KEYWORDS: Signal to noise ratio, Sensors, Signal detection, Interference (communication), Distance measurement, Heterodyning, Optical components, Interferometry, Environmental sensing, Interferometers, Precision measurement, Optical testing, Acousto-optics, Quality systems
High precision measurement of optical elements with long focal length is affected by vibration, airflow and other
environmental factors due to the long cavity length, which has been difficulty and hot issue in optical machining and
detection. In order to overcome the difficulties of high precision measurement of optical elements with long focal length,
the paper proposes a full-field heterodyne interferometric measurement technique that could effectively suppress the
environmental interference. In the early related research, a series of Hertz-level high-stability, low-differential frequency
acousto-optic frequency shifters were successfully developed, which could be applied to heterodyne interferometry,
instead of traditional phase-shifting intererometry. On this basis, a full-field heterodyne interference measurement system
is developed, using array detector with conventional frame rate for full-field detection, to solve the problem of different
optical paths of reference light and measuring light in dynamic interferometers. It could effectively suppress the vibration,
noise, airflow and other factors, and thus significantly improve measurement accuracy and environmental adaptability. In
typical environment with vibration and airflow, our measurement system can achieve technical indicators as follows:
surface measurement accuracy is better than λ/1000 and repeated measurement accuracy is better than 5λ/10000.
Thereby the new full-field heterodyne interferometry could be applied to dynamic measurement of large-diameter optical
components and systems quality inspection, system installation correction, on-line measurement and other areas.
