A paper was published in Science Advances, a sub-issue of Science, and scientists realized that under realistic conditions, a pulsed laser pointer was used to drive a continuous high-speed motion in pure water. Driving macroscopic material movement with a laser This is the first time since the invention of a laser to achieve the macroscopic driving force provided by the very weak photon direct energy or momentum transmission force.
This breakthrough result was found in the experiments of non-linear optical properties of gold nanoparticles by a joint research team of Chinese and foreign universities such as the University of Electronic Science and Technology of China, the Henan Institute of Engineering, and the University of Houston in the United States. Due to the weak nature of photon energy, The indirect driving force generated by the reaction has extremely high requirements for fluid properties, and transparent liquids such as water require very little absorption of excitation light.
According to Wang Zhiming, the main author of the paper, the key to the success of this experiment is actually the “gold nanoparticle microcavity.” The phenomenon of photoacoustic fluid effect is actually a combination of photoacoustic effect and acoustic wave driving effect. A microcavity shaped like a crater and attached with a large amount of gold nanoparticles are generated at the laser focus of the inner wall of the glassware. Gold nanoparticles undergo rapid, periodic volume expansion and contraction under the irradiation of a pulsed green laser pointer, generating ultrasound.