Sub-micrometer precision of optical imaging to locate the free surface of a micrometer fluid shape

摘要

In this note, we explore the precision of the optical imaging method for measuring the free surface position of a micrometer fluid shape. For this purpose, images of a liquid film deposited on a rod were acquired and processed. The resulting contour was compared with the corresponding solution to the Young-Laplace equation. The average deviation was about 30 nm, 25 times smaller than the pixel size, reflecting the validity of optical imaging for most applications in microfluidics.