Research On The Measurement Method Of ICF Target Surface Defects Based On White Light Micro-interferenc

Laser inertial confinement nuclear fusion(ICF)experiment is of great significance for the explosion simulation,astrophysics,etc.Fusion experiment has extremely high requirements for the surface morphology of ICF capsule used as fuel container,any defect of the ICF capsule may cause asymmetric compression,resulting in a decrease in experimental efficiency or even failure of the experiment.Therefore,the high-precision measurement of surface morphology of microspheres such as ICF capsule has important practical significance.According to the real height measurement of defects on the surface of microspheres such as ICF capsules,a null interferometric microscopy method based on vertical scanning white light interferometry is proposed to solve the problem of missing integer multiples of phase 2π at the defect jumps in existing measurement methods.The method adopts the concept of "white light spherical null interferometric microscopy ",combining white light interference technology with Linnik interferometric microscopy technology,and introducing a spherical surface as a reference mirror to realize the null interferometry of the ICF capsule in the full field of view,and obtain the true height morphology of ICF capsule.First,study the principle and difference between laser interference and white light interference technology.According to the characteristics of three different forms of optical micro-interference structures of Michelson,Mirau and Linnik,this paper proposes to combine the white light interference technology with the traditional Linnik microscopic interference imaging optical path,based on the concept of "white light spherical null interferometric microscopy ",the reference mirror is replaced with ideal smooth microsphere,and a null interferometric microscopy method based on white light interferometry is proposed for spherical surface measurement.In this paper,a high-precision piezoelectric ceramic driver is used to drive the ICF capsule along the optical axis to achieve vertical scanning spherical interference,and obtains the full field of view white light interferograms.Then,the seven-step phase-shifting algorithm and the bat-wing effects correction algorithm are used to calculate the surface defects morphology of ICF capsules.Finally,the white light interferometry is compared with the laser interferometry through experiments and the results show that the white light interferometry can effectively solve the problem of integer multiples loss of phase 2π at the defect jumps,realize the real height measurement of the ICF capsule surface defects,and extend the measurement range of microsphere surface defects.