Fig. 2: Effect of the birefringence of the mica substrates on excitation light.
From: Long axial range 3D single-particle tracking using birefringent substrates
a Schematic illustration of the birefringent characteristics of mica. α, β, and γ represent the principal optic axes of mica with refractive indices of nα, nβ, and nγ, respectively. a, b, and c are crystallographic axes. b Schematic illustration of the optical path of an excitation laser in a wide-field fluorescence microscope. The mica substrate has a thickness of d. β and γ represent the principal optic axes of the mica substrate. θ is the rotational angle of the mica substrate. c Transmittance of the 532 nm light through the mica substrate with different thicknesses. The solid line shows the fitting of the data to Eq. 3. d Thickness-dependent retardance of the mica substrates. e Schematic illustration of the polarization states of the excitation light that passes through the mica substrates. A linearly polarized excitation light passes through the mica substrate with its polarization direction parallel (left) and non-parallel (right) to one of the optic axes of the mica substrate.
