Nanometer-Scale Height Measurements in Micromachined Picoliter Vials Based on Interference Fringe Analysis

Micromachined picoliter vials in silicon dioxide with a typical depth of 6.0?m are filled with a liquid sample. Epiilluminated microscopic imaging during evaporation of the liquid shows dynamic fringe patterns. These fringe patterns are caused by interference between the direct part and the reflected part of an incident plane wave (reflected from the bottom of the vial). The optical path difference (OPD) between the direct and the reflected wave is proportional to the distance to the reflecting bottom of the vial. Evaporation decreases the OPD at the meniscus level and causes alternating constructive and destructive interference of the incident light resulting in an interferogram. Imaging of the spacevarying OPD yields a fringe pattern in which the isophotes correspond to isoheight curves of the meniscus. When the bottom is flat, the interference pattern allows monitoring of the liquid meniscus as a function of time during evaporation. On the other hand, when there are objects on the ...

• Type: Conference
• Year: 2000
• Where: ICPR
• Authors: L. R. Van den Doel, Lucas J. van Vliet, K. T. Hjelt, M. J. Vellekoop, Ian T. Young, F. Gromball, Jan G. Korvink
• Keywords: Computer Vision, Fringe Pattern, ICPR 2000, Interference Pattern, Liquid Meniscus