Extended Data Fig. 3: Interferometric analysis of bulge deflection.
From: A molecularly impermeable polymer from two-dimensional polyaramids
(A) Optical top-view images of a bulged-up 35-nm film after passing through three different bandpass filters. (B) Radial intensity profiles of the images shown in panel A. The position is normalized by the radius, a, of the membrane. Local minima correspond to fringes with destructive interference, local maxima to fringes with constructive interference. (C) Cross-sectional illustration of a microwell with a bulged-up film. The yellow arrows represent how the direction of the reflected light depends on the local slope, dδ/dr, of the film. The green shading underneath the film corresponds to the interference pattern for λ = 540 nm. Each fringe with radius ri corresponds to a displacement δi. The vertical distance between consecutive fringes is always λ/4. (D) All solutions to eqs. M13 and M14. Unphysical values are grayed out. For the fringes, bright colors correspond to maxima, dark colors to minima. A representation of the intensity as a function of deflection is shown on the right. The black line represents the extrapolated deflection profile δ(r) of the bulge.
