为了分析和研究激光聚焦位置对金纳米颗粒光致超声信号的影响,采用超声探测器探测超声的同时,利用CCD观测溶液状态。结果表明,当激光脉冲聚焦在比色皿中间时,产生的光声信号为悬浮在溶液中的金纳米颗粒在激光作用下的超声信号；当激光聚焦在比色皿内壁和溶液交界面时,金纳米颗粒光声信号持续时间增加并且变得杂乱,此时,如果超声信号出现周期性振荡,金纳米颗粒溶液从激光聚焦点开始,沿激光方向发生高速流动。此研究对开辟新的微流控研究领域有一定参考意义。

In order to analyze and study the influence of laser focusing position on photoasound signal of gold nanoparticles, ultrasound detectors were used to detect ultrasound and the state of solution was observed by CCD. The results show that, when the laser pulse is focused in the middle of the colorimeter, the photoacoustic signal is the ultrasonic signal of gold nanoparticles suspended in solution under the action of laser. When the laser is focused on the interface between the inner wall of the colorimetric dish and the solution, the photoacoustic signal duration of gold nanoparticles increases and becomes disordered. In this case, if the ultrasonic signal oscillates periodically, the solution of gold nanoparticles starts from the laser focus and flows at high speed along the laser direction. This research has certain reference significance for opening up a new research field of microfluidics.