title: Stroboscopic scanning white light interferometry at 2.7 MHz with 1.6 µm coherence length using a non-phosphor LED source.
abstract: Stroboscopic scanning white light interferometry (SSWLI) allows precise three dimensional (3D) measurements of oscillating samples. Commercial SSWLI devices feature limited pulsing frequency. To address this issue we built a 400-620 nm wideband 150 mW light source whose 1.6 µm wide interferogram is without side peaks. The source combines a non-phosphor white LED with a cyan LED. We measured a calibration artifact with 10 nm precision and obtained 40 nm precision when measuring the 3D profile of a capacitive micromachined ultrasonic transducer membrane operating at 2.72 MHz. This source is compatible with solid state technology.
authors.affiliation: Department of Physics, University of Helsinki, PO Box 64, 00014 Helsinki, Finland. ville.heikkinen@helsinki.fi
authors.forename: Ville
authors.initials: V
authors.lastname: Heikkinen
authors.forename: Ivan
authors.initials: I
authors.lastname: Kassamakov
authors.forename: Tor
authors.initials: T
authors.lastname: Paulin
authors.forename: Anton
authors.initials: A
authors.lastname: Nolvi
authors.forename: Edward
authors.initials: E
authors.lastname: Hæggström