(a) LANDs consist of a perfluorohexane core with encapsulated optical trigger (e.g., dye) and a stabilizing shell. (b) LANDs are vaporized by a pulsed laser irradiation (left). In their transient microbubble state, acoustic waves are reflected, providing ultrasound contrast. The LANDs recondense one at a time after the vaporization and no longer produce ultrasound contrast. (c) Ultrasound images before the laser trigger, immediately following the laser pulse, 30 ms after the laser pulse, and 60 ms after the laser pulse (from left to right) show the blinking behavior of LANDs.