Figure 2
From: Optical diffraction for measurements of nano-mechanical bending
(a) Normalized differential photodiode signal versus beam position (assumed proportional to cantilever bending) for an infinite detector at different observation distances, in solid lines considering the diffraction caused by the cantilever edge and in dashed lines neglecting diffraction. (b) Magnitude of the fractional error as a function of beam position in units of σ for different conditions λz/σ2 = 1, 2, 5, 10 and 20 in colours black, brown, red, orange and green respectively. The error as a consequence of neglecting the diffraction phenomena can surpass 10% in some cases.
