Timeline for Lens metrology: How to measure a double-sided thick aspherical lens optically?
Current License: CC BY-SA 4.0
4 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| May 7, 2018 at 2:47 | vote | accept | WDC | ||
| May 7, 2018 at 2:45 | comment | added | JB2 | Aspheric interferometers look at the reflection from (usually) uncoated surfaces. They commonly use He-Ne lasers at 632.8 nm, as these lasers are cheap and have a long coherence length. Other wavelengths don't provide significant advantage for measuring uncoated optics - the reflection coefficient is usually close to 4% and not that sensitive to wavelength. For more information, look on websites of companies that make these interferometers, like Zygo, Wyko, ESDI, or 4D. | |
| May 6, 2018 at 17:55 | comment | added | WDC | Thanks for such an elaborative answer. So the conclusion for my question is "hard and probably impossible". Could you expand a little more on 2) aspheric interferometers? How can we measure surfaces solely? By reflecting lights from the surfaces? When the lens is just a piece of glass (without coatings), how to decide which wavelength to use to shine light onto the surfaces? | |
| May 6, 2018 at 17:13 | history | answered | JB2 | CC BY-SA 4.0 |