Figure 5.

(a) The time trace of the photocounts per micrometer of a single DNA strand for power densities of 62 W cm⁻² (red), 38 W cm⁻² (orange), 23 W cm⁻² (green), 10 W cm⁻² (blue), and 1.9 W cm⁻² (violet). (b) Image of a DNA molecule at different times of the video. All images have the same color scale. A laser power density of 38 W cm⁻² was used.