针对目前原子力显微镜等方法只能测量激光惯性约束核聚变(ICF)靶丸外表面等难题, 研制了高精度、非接触、小型化的激光差动共焦传感器(LDCS)。该传感器基于差动共焦原理, 利用激光差动共焦轴向响应曲线的零点对靶丸内外表面和球心分别进行定位, 并结合物镜微位移驱动技术, 实现靶丸内外表面和壳层厚度的高精度测量。该方法减少了靶丸表面的反射率、倾斜等因素对测量瞄准特性的影响, 显著提高了系统的抗干扰能力。将传统的显微成像与差动共焦测量光路进行有机融合, 实现了对被测样品的精确瞄准。初步实验与理论分析表明：当测量物镜的数值孔径NA为0.65时, LDCS的轴向分辨力优于5 nm, 信噪比优于1 160, 过零点的标准偏差为10 nm。该传感器为激光惯性约束核聚变靶丸测量提供了一种新的技术途径。

As Atomic Force Microscope can only measure the outside surface of a capsule in the Inertial Confinement fusion (ICF) , a high precision, non-contact, miniaturized Laser Differential Confocal Sensor (LDCS) is developed. Based on the differential confocal principle, the sensor positions respectively the test points on the outer surface, inner surface and spherical center of the ICF capsule in sequence by the absolute zero point of a laser differential axial intensity curve. Then it implements the high-precision measurement of the ICF capsule by combing with the high precision displacement sensor. This method reduces the influences of the surface reflectivity and tilt of the capsule and other factors on pointing characteristics and improves the anti-interference ability. Combining the traditional microscopic imaging and differential confocal optical path organically, the precision pointing is achieved. Theoretical analysis and preliminary experiments indicate that the axial resolution of LDCS is better than 5 nm, the standard deviation of absolute zero is 10 nm and the signal to noise ratio is better than 1160 when the Numerical Aperture(NA) is 0.65. The sensor provides a new way for measuring capsules in the ICFs.