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2020-12-09

Ultra-thin Windows with High Flatness

Femto-line lasers and applications are developing fast in recent years, some demanding components are needed to make Femto-line laser systems, one of them is the small thickness (such as 0.1mm, 0.2mm) windows or substrates with high flatness (Lambda/10 or Lambda/4 @633nm).

Classical single surface polishing method are often used to make the high precision laser grade optics products, but it is difficult to make the high flatness optics with small thickness using classical method. For the polished optics is often put on pitch plate in polishing processing , even though you get a high quality surface (high surface quality and high flatness) in polishing, when it is taken off pitch plate, the flatness would be lowered, because there is stress in the optics when it is bonded to pitch, when it is taken off pitch plate, the stress would be released, the flatness would be lowered in the stress releasing, for the small thickness one, the flatness would become very lower. To get high flatness and ultra thin windows is always challenging for manufacturers.

Hangzhou Shalom EO develop a double surface polishing method to make the high precision optical windows or substrates, the double surface are polished in single polishing processing,  the optics don’t need to be put on pitch plate in the polishing, and there is no stress releasing problem, there would be no flatness change when it is taken from tools. Double surface polishing method is not used in precise optics fabrication previously because the finished optics is low surface quality, Hangzhou Shalom EO has done improvements on polishing machine, and the 10/5 S/D is get. And furthermore, the parallelism is excellent (10 arc sec) for this polishing windows. 

By our improved double surface polishing machine, we can make the laser grade small thickness windows and substrate like following (materials: BK7 or fused silica):

Ultra Thin Windows with High Flatness:

Size of Windows Flatness (@633nm) Surface Quality Parallelism
D12.7x0.1mm 1/4 10/5 S/D <10 arc sec
D12.7x0.2mm 1/4 10/5 S/D <10 arc sec
D25.4x0.1mm 1/2 10/5 S/D <10 arc sec
D25.4x0.2mm 1/4 10/5 S/D <10 arc sec
D25.4x0.3mm 1/4 10/5 S/D <10 arc sec
D25.4x0.6mm 1/8 10/5 S/D <10 arc sec
If you search standard size products click here