Garbos M K, Euser T G, Russell P St J
Max Planck Institute for the Science of Light, Günther-Scharowsky-Str. 1/Bau 24, 91058 Erlangen, Germany.
Opt Express. 2011 Sep 26;19(20):19643-52. doi: 10.1364/OE.19.019643.
We study the conditions under which a particle, laser-guided in a vertically-oriented hollow-core photonic crystal fiber filled with liquid, can be kept stationary against a microfluidic counter-flow. An immobility parameter-the fluid flow rate required to immobilize a particle against the radiation force produced by unit guided optical power-is introduced to quantify the conditions under which this occurs, including radiation, viscous and gravity forces. Measurements show that this parameter depends strongly on the ratio of particle radius a to core radius R, peaking at an intermediate value of a/R. The results follow fairly well the theoretical estimates of the optical (calculated approximately using a ray optics approach) and numerically simulated drag forces. We suggest that the system has potential applications in, e.g., measurement of the diameter, refractive index and density of particles, synthesis and biomedical research.
我们研究了在充满液体的垂直取向空心光子晶体光纤中激光引导的粒子能够抵抗微流体逆流而保持静止的条件。引入了一个固定参数——使粒子抵抗单位引导光功率产生的辐射力而固定所需的流体流速，以量化发生这种情况的条件，包括辐射力、粘性力和重力。测量结果表明，该参数强烈依赖于粒子半径a与纤芯半径R的比值，并在a/R的中间值处达到峰值。结果与光学（近似使用光线光学方法计算）和数值模拟的阻力理论估计相当吻合。我们认为该系统在例如粒子直径、折射率和密度的测量、合成以及生物医学研究等方面具有潜在应用。
