Figure 4.17 — Evanescent focus

Fig. 4.17 — Evanescent focus
Figure 4.17 — Evanescent focus. Intensity distribution at the focus of a 1.45 NA total internal reflection objective with aperture radius of 4 mm for (a) an x-polarised Gaussian beam with beam waist w0 = 4 mm and for (b) a radially polarised and (c) an azimuthally polarised cylindrical vector beam in the presence of a glass (nt = 1.55)–water (ns = 1.33) interface placed at zi = 0 μm. All beams have wavelength λ0 = 632 nm and the full laser power after the aperture is 10 mW. The iso-intensity surfaces correspond to I(x,y,z)=50, 20, 10, 5 GW/m2.