Optical material removal property analysis of Ar+ and Kr+ in ion beam figuring

Ion beam figuring (IBF) provides a highly deterministic method for the final precision figuring of optical components. According to the Sigmund sputtering theory, the mass of incident ions is an important factor to the sputtering rate and the optical surface quality. Both Ar + and Kr + are alternative ions in IBF, but the mass of Kr + equals two times that of Ar + . In order to achieve the nanometer and sub-nanometer precision fabrication with IBF, the optical material removal property of Ar + and Kr + ions was researched. The bombardment process had been simulated with the software TRIM, and the sputtering yield of Ar + and Kr + ions for different incident angles was calculated. Then the removal function experiments on Si were conducted. The simulations and experiments result indicated that Ar + ion beam achieves higher removal rate at 0° incident angle, but Kr + ion beam performs more efficiently when the incident angle gets across a critical point.