Fig. 1.

Schematic diagram of the apparatus. Flipper mirrors: F1 was used to switch between 920 nm and 1300 nm lasers; F2 and F3 were used to switch between the Gaussian and Bessel beam excitation. Axicon, α = 2 degrees. Lenses: L1 and L2, 50 mm (or 75, 100 mm) focal length, determines the effective excitation NAs and lengths of the Bessel beam. L3 (100 mm), L4 (100 mm), SL (54 mm) and TL (200 mm) were used to create multiple conjugate planes of the back focal plane (BFP) of the objective in the light path; L5, collection lens (30 mm). Galvo mirrors: GMX/GMY, for the x/y direction of beam scanning. DM, 735-nm long-pass dichroic mirror; a 770-nm short pass filter and a 525/40 nm bandpass filter were used here (Filters) for emission collection.