Surface Bubble Dynamics in Plasmonic Nanoparticle Suspension

Optically Driven Gold Nanoparticles Seed Surface Bubble Nucleation in Plasmonic Suspension

Photothermal surface bubbles play important roles in a wide range of applications like catalysis, microfluidics and biosensing, but their formation on a transparent substrate immersed in a plasmonic nanoparticle (NP) suspension has an unknown origin. Here, we show that NPs deposited on the substrate by dispersive optical forces are responsible for the nucleation of such photothermal surface bubbles. High-speed videography shows that the surface bubble formation is always preceded by the optically driven NPs moving toward and adhering to the surface. We observe that the thresholds of laser powe…

微通道内远场等离子体共振增强纳米粒子图像测速

Far-Field Plasmonic Resonance Enhanced Nano-Particle Image Velocimetry within a Micro Channel

在本文中，一种新型的远场等离子体共振增强纳米粒子种子粒子图像测速（nPIV）已被证明是测量微通道中的速度分布。化学合成的银纳米粒子已被用于在微通道中的种子流。采用离散偶极近似（DDA）方法，计算了直径为15 ~ 200 nm的球形银纳米粒子的等离子体共振增强光散射。确定了纳米粒子在水和空气两种介质中的最佳散射波长。记录并分析了不同直径银纳米粒子的衍射极限等离子体共振增强图像。通过使用标准的PIV技术，已确定的微通道内的速度分布从图像。

Surface Bubble Growth in Plasmonic Nanoparticle Suspension

Understanding the growth dynamics of the microbubbles produced by plasmonic heating can benefit a wide range of applications like microfluidics, catalysis, micro-patterning and photo-thermal energy conversion. Usually, surface plasmonic bubbles are generated on plasmonic structures pre-deposited on the surface subject to laser heating. In this work, we investigate the growth dynamics of surface microbubbles generated in plasmonic nanoparticle (NP) suspension. We observe much faster bubble growth rates compared to those in pure water with surface plasmonic structures. Our analyses show that the…

Gas bubble photonics: Manipulating sonoluminescence light with fluorescent and plasmonic nanoparticles

Oscillations of gas bubbles in liquids irradiated with acoustic pressure waves may result in an intriguing physical phenomenon called sonoluminescence, where a collapsing bubble emits the light in a broad optical spectral range. However, the intensity of the so-generated light is typically weak for practical purposes. Recently, it has been demonstrated that nanoparticles can be used to increase the efficiency of sonoluminescence, thereby enabling one to generate the light that is intense enough for a number of applications in photonics, biomedicine and material science. In this article, we rev…

Light-Guided Surface Plasmonic Bubble Movement via Contact Line De-Pinning by In-Situ Deposited Plasmonic Nanoparticle Heating

Precise spatio-temporal control of surface bubble movement can benefit a wide range of applications like high-throughput drug screening, combinatorial material development, microfluidic logic, colloidal and molecular assembly, etc. In this work, we demonstrate that surface bubbles on a solid surface are directed by a laser to move at high speeds (> 1.8 mm/s), and we elucidate the mechanism to be the de-pinning of the three-phase contact line (TPCL) by rapid plasmonic heating of nanoparticles (NPs) deposited in-situ during bubble movement. Based on our observations, we deduce a stick-slip mecha…

金纳米颗粒悬浮液中的电-热-等离子体流动：非线性流速对聚集体浓度的依赖性

Electro-Thermo-Plasmonic Flow in Gold Nanoparticle Suspensions: Nonlinear Flow Velocity Dependence with Aggregates Concentration

本研究结合模拟与实验，发现金纳米颗粒悬浮液在激光和电场作用下产生的电热等离子体流动速度与颗粒浓度呈非线性关系，源于多重散射吸收增强，并可用于实现高速流动。