Fig. 1. TrL method for observation of FS-laser-induced structural change inside water. In the lower diagram, the deformation process of the beam profile is depicted. DP, detection plane; SPM, spatial phase modulation; ID, intensity distribution.

Fig. 2. Experimental setup for the pump-probe microscope. WP, 1036 nm 1/2 wave plate; PBS, polarized beam splitter; L, lens; F, 950 nm short-pass filter; DL, delay line; S, sample; M, mirror; OBJ, objective lens; DM, dichroic mirror; C, camera; T, terminator.

Fig. 3. Typical transient maps at different relative pump-probe delay time after excitation with water by the pump pulse. The pulse energy densities corresponding to the four rows’ images are as follows:1.77, 2.15, 2.77, and 3.72 J/cm².

Fig. 4. (a) Schematic diagram of dark spot formation^[31], Region 1, plasma shielding area; Region 2, deflected light accumulating area. (b) Transient maps at 6.6 ps after excitation by a pump pulse with an energy density of 3.72 J/cm².

Fig. 5. Evolution of the spot diameter modulated by plasma shielding and TrL; (I) plasma recombination (black square); (II) plasma recovery (star); (III) shockwave and water vapor expansion (white square). (a) 2.77 J/cm²; (b) 3.72 J/cm².