Onto Innovation Inc.
Interferometry with pixelated color discriminating elements combined with pixelated polarization masks

Abstract:

A pixelated color mask is combined with a pixelated polarization mask in dynamic interferometry. The color mask includes a wavelength-selective bandpass filter placed in front of each camera pixel such that each set of contiguous four camera pixels is covered by two green bandpass filters, a red bandpass filter, and a blue bandpass filter. The pixelated phase mask is coupled to the color filters such that one polarization filter covers one set of color filters. At least three polarization filters are used to calculate phase. In addition, the color signals can be used, for example, to encode the motion of the interferometer, to provide very high speed autofocus or tip/tilt feedback, to create a color image of the object being measured, to automatically focus the system at different positions for different measurements conducted with different color sources, and to perform heterodyne interferometry with a single, vibration-immune measurement.