Abstract

Currently, ion beam figuring (IBF) technology has presented many excellent performances in figuring potassium dihydrogen phosphate (KDP) crystals, such as it is a noncontact figuring process and it does not require polishing fluid. So, it is a very clean figuring process and does not introduce any impurities. However, the ion beam energy deposited on KDP crystal will heat the KDP crystal and may generate cracks on it. So, it is difficult directly using IBF technology to figure KDP crystal, as oblique incident IBF (OI-IBF) has lower heat deposition, higher removal rate, and smoother surface roughness compared to normal incident IBF. This paper studied the process of using OI-IBF to figure KDP crystal. Removal rates and removal functions at different incident angles were first investigated. Then heat depositions on a test work piece were obtained through experiments. To validate the figuring process, a KDP crystal with a size of $200\mathrm{mm}\times 200\mathrm{mm}\times 12\mathrm{mm}$ was figured by OI-IBF. After three iterations using the OI-IBF process, the surface error decreases from the initial values with PV $1.986\lambda$ RMS $0.438\lambda$ to PV $0.215\lambda$ RMS $0.035\lambda$. Experimental results indicate that OI-IBF is feasible and effective to figure KDP crystals.

© 2017 Optical Society of America

Research on temperature field of KDP crystal under ion beam cleaning

Furen Li, Xuhui Xie, Guipeng Tie, Hao Hu, and Lin Zhou
Appl. Opt. 55(18) 4888-4894 (2016)

Mitigation of subsurface damage in potassium dihydrogen phosphate (KDP) crystals with a novel abrasive-free jet process

Wei Gao, Jianwei Ji, Chao Wang, Lili Wang, Qichao Fan, Kaihua Sun, Fang Ji, and Min Xu
Opt. Mater. Express 8(9) 2625-2635 (2018)

Novel abrasive-free jet polishing mechanism for potassium dihydrogen phosphate (KDP) crystal

Wei Gao, Lili Wang, Lunfu Tian, Pengfei Sun, Hui Dong, Xiaoyuan Li, Chao Wang, and Min Xu
Opt. Mater. Express 8(4) 1012-1024 (2018)

Scalable process for mitigation of laser-damaged potassium dihydrogen phosphate crystal optic surfaces with removal of damaged antireflective coating

S. Elhadj, W. A. Steele, D. S. VanBlarcom, R. A. Hawley, K. I. Schaffers, and P. Geraghty
Appl. Opt. 56(8) 2217-2225 (2017)

Research of polishing process to control the iron contamination on the magnetorheological finished KDP crystal surface

Shaoshan Chen, Shengyi Li, Xiaoqiang Peng, Hao Hu, and Guipeng Tie
Appl. Opt. 54(6) 1478-1484 (2015)