Optical Metrology

Microsystems & Metrology

Modern interferometry using digital signal processing offers nanometer resolution. Commercially available laser diodes, as commonly used in CD players, can be frequency stabilized to obtain high absolute accuracy. Absolute distance and displacement measurement by optical interferometry is possible using multiple wavelength sources. We apply such principles to high precision position measurement for atomic force microscopes and multiple wavelengths interferometry for scanning near field optical probes. Statistical interference patterns (Speckles) are studied to identify the limits of miniaturized systems for displacement measurement.