Fringe modulation skewing effect in white-light vertical scanning interferometry.

Fundamental aspects of resolution and precision in vertical scanning white-light interferometry

Wediscuss the height and lateral resolution that can be achieved in vertical scanningwhite-light interferometry (SWLI).With respect to interferometric height resolution, phase-shifting interferometry (PSI) is assumed to provide the highest accuracy. However, if the noise dependence of SWLI phase evaluation and PSI algorithms is considered, SWLImeasurements can be shown to bemore precise.With re...

Harnessing spectral property of dual wavelength white LED to improve vertical scanning interferometry.

Unlike a conventional white light source that emits a continuous and broad spectrum of light, the dual wavelength white light emitting diode (LED) generates white light by mixing blue and yellow lights, so there are two distinct peaks in its intensity spectrum. Prior works had shown that the spectral property of the dual wavelength white LED can affect the vertical scanning interferometry negat...

Reduction of chromatic aberration influences in vertical scanning white-light interferometry

Vertical scanning white-light interferometry (SWLI) is a well-established method that is widely used in high precision surface topography measurement. However, SWLI results show characteristic slope-dependent errors due to dispersion effects and lateral chromatic aberrations of the optical imaging system. In this paper, we present methods to characterize these systematic errors related to dispe...

Improved vertical-scanning interferometry.

We describe a method that combines phase-shifting and coherence-peak-sensing techniques to permit measurements with the height resolution of phase-shifting interferometry without the interval-slope limitation of lambda/4 per data sample of phase-shifting interferometry. A five-frame algorithm is used to determine both the best-focus frame position and the fractional phase from the best-focus fr...

Phosphor-Based White Light Emitting Diode (LED) for Vertical Scanning Interferometry (VSI)