面向超分辨光学成像的浸没微球透镜控制

Control of liquid-immersed submerged microsphere for super-resolution optical imaging

微球透镜配合传统光学显微镜可以采集到衍射极限以下的超分辨光学图像,为了精确控制微球透镜在样品表面的位置,同时扩大超分辨成像范围,提出了一种控制微球透镜的方法,结合多轴微动平台实现微球透镜的精确定位与成像扫描操作。通过光学仿真分析了微球透镜超分辨成像效果,并对精密微动平台进行了运动学分析。为了提高超分辨成像效果,将微球透镜浸没于液体介质中,并对在液体中运动的微球透镜进行力学分析。通过实验,清晰分辨出130nm(~λ/4)的蓝光光碟条纹间隙,证明了微球透镜具有超分辨成像能力,结果表明,微球透镜可以在传统光学显微镜的基础上进一步提高约3.52倍的放大倍数。通过控制微球透镜以5×10^(-6) m/s的速度在液体中按"S"型轨迹移动,实现了对一个视场内样品的超分辨成像,此控制方法可以精确控制微球透镜的运动,通过扫描的方式可以扩大微球透镜的观测范围,提高观测速度。

Images with resolution beyond the diffraction limit can be achieved by combining conventional microscopy with a microsphere.In order to position the microsphere on the field of interest of the sample surface and to expand the observation area,a method to manipulate the microsphere by combining it with a multi-axis translation stage was proposed in this paper.Images were obtained by scanning the microsphere,which was positioned accurately by driving the translation stage with four degrees of freedom.The influence of the probe on the super-resolution image was analyzed by performing an optical simulation.Kinematic analysis of the translation stage was studied for determining the manipulation strategy of the microsphere.Force analysis of the microsphere in a liquid medium was carried out to evaluate the possibility of detachment of the microsphere from the probe.By using a microsphere,the gap between the Blu-ray disc stripes could be clearly observed.The experimental results indicate that the amplification factor of the microsphere is 3.52 andaresolution of 130 nm（approximatelyλ/4）can be achieved.In addition,by scanning the microsphere along the S-shaped trajectory at a speed of 5×10^-6 m/s over the sample surface,the super-resolution image over a large continuous area was achieved.Therefore,by using this method,the imaging area could be expanded and the observation efficiency was improved.