基于光电效应的动态可控声镊器件基础研究及其在微/纳流控领域的开发应用

Dynamic manipulation of mciro/nano particles is generally involved in every step of microfluidics, especially for micro-total-analysis-system (μTAS) and Lab-on-a-Chip (LOC). Due to the thermal effect, the Browian motion of micro/nano particles makes their manipulation challenging. This project presents a novel active method to achieve the dynamic manipulation of these small particles through an optoelectronic-induced dynamic acoustic tweezers. To do so, firstly we grow a n+-p-n phototransistor on top of a piezoelectric (e.g. LiNbO3) substrate. Then a digital-mirror-display (DMD) is used to project a light beam with an interdigital transducers (IDT) geometry on the piezo substrate, which turns on the phototransistor and forms virtual IDTs. Applying AC signal to the virtual IDTs generates surface acoustic waves, which functions as acoustic tweezers to manipulate micro/nano particles. Tuning the DMD projection changes the position\size\frequency of the acoustic tweezers, thus realizing the dynamic manipulaton of particles. We also present to develop a series of applications based on this technology, in the field of μTAS, LOC, nano optics (inspecfic active plasmonics). We would focus on solving the key challenges in device machining, on-chip integration of optoelectro- and acoustic components. The presented idea and technical solution would span a new era in micro/nano-fluidics, and would also benefit fields beyond that, say micro/nano-optics, active plasmonics, and materials.

微纳颗粒操控几乎涵盖于微流控技术尤其是微全分析系统以及芯片实验室的各个试验环节,也是其中最具挑战性的难题。本课题创新性的提出一种基于光电效应的动态可控声镊器件的设计思想和实现方法,旨在通过该器件建立一个通用的在片集成微纳颗粒操控平台,并实现一系列在生物、化学以及纳米光学领域的应用。本项目将涵盖以下关键技术流程：1）实现在压电衬底上外延生长n+-p-n双极光电晶体管；2）通过数字微镜(DMD)光投射在压电光电晶体管表面形成动态可控的虚拟叉指换能器，并通过其生成的声表面波而构成声镊；3）通过编程数字微镜光投射来实现对声镊位置、形态、工作频率的调控，实现对微纳颗粒的全操作；4）通过在片集成，利用光电声镊开发一系列多功能微流控芯片。我们将着重解决器件微/纳加工以及在片光电和超声器件集成等领域的难题。研究成果可广泛应用于涉及微纳颗粒操控的微/纳流控器件；同时也可在纳米光学和材料领域开辟新的用途。

本项目针对微流控技术中微纳颗粒操控的需求，提出了基于光电效应的动态可控声镊器件研究。基于有限元仿真工具comsol，完成了声镊器件中声表面驻波的有限元仿真，优化了器件设计参数。利用流体与声场的耦合仿真，分析了流道中纳米颗粒在声表面驻波控制下的轨迹，并分析了声表面波频率、几何尺寸等对颗粒操控效果的影响。基于微纳加工工艺完成了基于声表面驻波的声镊器件加工和测试，实现了流道中微纳颗粒的操控。针对光电控制集成微纳平台的需求，开展了基于不等高梳齿的离面静电驱动器研究，利用光刻胶填充刻蚀技术改进了不等高梳齿结构加工工艺，提高了加工成品率。利用优化后的工艺完成了用于微透镜控制的离面静电驱动器设计和加工，实现了12微米的离面驱动范围。开发了微透镜闭环控制技术，可以根据设定参数控制透镜位置，解决重力和振动对微镜位置的影响。