Correction of high spatial frequency errors on optical surfaces by means of ion beam figuring

2007 ◽  
Author(s):  
M. Ghigo ◽  
R. Canestrari ◽  
D. Spiga ◽  
A. Novi
Keyword(s):  
Spatial Frequency ◽  
Ion Beam ◽  
High Spatial Frequency ◽  
Optical Surfaces ◽  
Ion Beam Figuring

Ion Beam Figuring Fabricate Effect with Different Removal Sizes

2013 ◽  
Vol 552 ◽  
pp. 142-146
Author(s):  
Yong Qiang Gu
Keyword(s):  
Spatial Frequency ◽  
Ion Beam ◽  
Influence Factors ◽  
Frequency Range ◽  
Surface Errors ◽  
Power Spectral ◽  
The Difference ◽  
Lens Surface ◽  
Ion Beam Figuring

Ion Beam Figure (IBF) is believed to be one of the most effective technics that can fabricate lens with nano or even sub-nano accuracy. For different sizes of IBF removal functions, the correct effects in different spatial frequency range are different. Power Spectral Density (PSD) curve can describe surface errors in full spatial frequency range, so it is a very convenient way to evaluate the quality of lens’ surface. In this paper, firstly, the principles of IBF and PSD are introduced briefly; Secondly, IBF removal functions with sizes from 2 mm to 15 mm are generated. A lens with surface error more than PV value 400nm is simulated with different sizes of IBF removal functions by Lucy-Richardson algorithm. Finally, experiments are done by IBF plant. A lens is fabricated by different sizes of removal functions and the fabricate results are tested by interferometer precisely and calculated to PSD curves. By the comparison of these curves, the IBF fabricate effects with different removal sizes are analyzed, which show that the smaller the removal size, the better the removal effect in higher spatial frequency range, but in the meantime, it will take a much longer time. Also the reasons of the difference between theory simulation and actual fabrication result are taken into account, and several influence factors are analyzed.

Process Prediction for Low-Energy Ion Beam Figuring Based on BH Modified Model

2013 ◽  
Vol 552 ◽  
pp. 238-243
Author(s):  
Zhi Chao Wang ◽  
Hua Dong Yu ◽  
Da Seng Wang ◽  
Chun Yang Wang
Keyword(s):  
Incident Energy ◽  
Ion Beam ◽  
Low Energy ◽  
The Self ◽  
Contact Method ◽  
Optical Surfaces ◽  
Self Organized ◽  
Beam Parameters ◽  
Ion Beam Figuring ◽  
Ripple Pattern

Ultra-smooth optical surfaces are very important in widely fields. They’re not only used in optics, but also in the electronics. Ultra-smooth surfaces are difficult to process, because the rms is less than 1nm. The process methods have Teflon Polishing, Float Polishing (FP), Magnetorheological Finishing (MRF) and Ion Beam Figuring (IBF) etc. Compared with conventional polishing, IBF have higher processing quality and efficiency. Low-energy (<2Kev) IBF can form the self-organized nanopatterns on optical surfaces. Since IBF is a non-contact method; there is no edge effect during the process. We can change the ion beam parameters to get dot or ripple pattern on substrate. Only the self-organized ripple pattern is discussed in the paper. For the prediction of process parameters, the principle theories Sigmund theory and BH model are used the interplay between the angle of ion beam incidence, ion flux, incident energy and substrate temperature leads to the self-assembly, which are considered by these theory. In this paper the angle of incidence and incident energy are mainly researched on. Processing nanopatterns on Si has been simulated by SRIM program with these theory and the results reveal several laws in the process. It is believed that these laws will help us to well predict the ion beam parameters and lead IBE experiments.

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