A compact real-time high-speed high-resolution vibrometer, surface profiler and dynamic focus tracker using three wavelengths parallel phase-shift interferometry

The combination of simultaneous parallel phase shift interferometry with three wavelengths illumination and three spectral quad detectors integrated into a compact optical system is presented, achieving a real time, high speed, sub-nm axial resolution and repeatability tracking of axial position over tens of micrometers including sharp step profiles. The prototype system is tested and demonstrated for the applications of fast vibrometry up to 400 kHz rate, surface profiling and dynamic focus tracking and correction. The methodology, algorithm and calibration procedure along with the new compact and low-cost system design relying on off the shelf components, are described in detail.