高分辨力分光瞳差动共聚焦传感技术研究

High-resolution divided-aperture differential confocal sensing technique

为了提高现有共聚焦传感技术的轴向分辨力、实现微观形貌的高精度测量,在提出分光瞳差动共聚焦传感技术的基础上,对其关键参数优化理论进行了进一步研究,并研制了一种具有最优参数的分光瞳差动共聚焦显微传感器,其融合了分光瞳差动共聚焦显微技术和基于可编辑探测器件的虚拟针孔技术,利用探测区域偏移可使分光瞳共聚焦显微技术轴向特性曲线产生相移这一特性,沿特定方向在探测面上对称设置两个虚拟针孔,通过探测它们的强度响应并进行差动处理实现高轴向分辨力、高定位精度测量。对所研制的传感器进行了轴向响应特性及传感器非线性验证,给出了其轴向相对位移测量公式,还利用所研传感器对实际的高度标准样品进行了测量,经实验验证,所研传感器轴向分辨力可达5 nm,横向分辨力为0.82μm,为微细结构三维表面的高精度测量提供了一种新的传感技术及系统。

In order to improve axial resolution of the confocal sensor and realize high accuracy measurement of micro-topography, the split-pupil differential confocal sensing technique is proposed. The key parameter optimization theory is further studied, and a divided- aperture differential confocal microscopic sensor with optimal theoretical parameters is developed. The developed sensor combines divided-aperture differential confocal microscopy and virtual pinholes based on editable detection device. The offset of the detection area can bring the phase offset of the axial characteristic curve in the divided-aperture confocal microscopy. Two virtual pinholes are set symmetrically on the detection surface in a specific direction, whose responses are obtained and differentially processed to achieve high axial resolution and high positioning accuracy measurement. The developed sensor are tested The axial response, nonlinear property of the developed sensor are evaluated and the actual sample is measured. The axial relative displacement measurement formula is obtained. Experimental results indicate that the axial resolution of the developed sensor is 5 nm and the lateral resolution is 0.82μm, which can provide a new sensing technology and system for the high-precision measurement of the three-dimensional surface of the microstructure.