Figure 3
US flow and PA images of the microdroplets in transparent tubes: (A) US flow imaging with flow speed of 11 mm/s (a,c) and 45 mm/s (b,d). The white arrow indicates the flow direction (B) PA images with laser energy 4.7 mJ/pulse (subfigure a)) and 14 mJ/pulse (subfigure b)). The irradiation wavelength is 750 nm.
