Chromatically dispersed interferometry with wavelet analysis.
A new white-light interferometry point sensor utilizing a chromatically dispersed depth detection field is addressed. Monitoring the interference in the optical frequency domain allows for microscopic height detection without the necessity of a mechanical axial scan. The problem of limited dynamic range in previously reported spectral interferometric schemes is solved by forming a high-contrast interference window due to the chromatically dispersed focusing of the detection field. In a proof-of-principle experiment, the position of a reflecting object could be retrieved with a focus of 0.8 NA over an axial range of 30 microm by analyzing the phase of the emerging interference wavelets.
Institut für Technische Optik, Universität Stuttgart, Pfaffenwaldring 9, 70569 Stuttgart, Germany. papastav@ito-uni-stuttgart.de
Evangelos
E
Papastathopoulos
Klaus
K
Körner
Wolfgang
W
Osten