What Is the Benefit of Coherent Detection in Metrology?
Optical imaging is widely used for metrology in applications where the added advantage of non-contact measurement, increased measurement range and higher scanning speed is needed – while still achieving the same accuracy and reliability as with the tactile scanning probe method. The non-invasive nature of optical metrology ensures that the samples controlled are left untouched.
The common path of transmitted and returned signal and long imaging range due to the long coherence length makes it possible to do imaging of very narrow deep features.
Compared to conventional confocal microscopy the speed of VCSEL SS-OCT makes it possible to increase the data acquisition by a factor of 50 to 500
The coherent detection makes it immune to ambient light.
OFDR can be used for faster and more precise metrology for everything from laser machining to coordinate measurement machines. For metrology, the use of coherent detection makes it possible to achieve a very high sensitivity and dynamic range of OFDR.