howto:align_beam_backreflection
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howto:align_beam_backreflection [2015/11/05 16:39] – [Image on the beam diagnostics camera during focusing] sisamakis | howto:align_beam_backreflection [2022/08/29 10:58] – [Image on the beam diagnostics camera during focusing] peter | ||
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- | {{tag> | + | {{tag>howto MicroTime200 |
====== Image on the beam diagnostics camera during focusing====== | ====== Image on the beam diagnostics camera during focusing====== | ||
+ | Users are often surprised by the pattern of fringes seen by the focus diagnostics camera. The video below shows the behavior of back-reflection of a well aligned polarized laser beam from the upper surface of a clean, empty coverslip. (Glass-air interface; inverted microscope with UPlanSApo 60x, NA = 1.2, water immersion objective.) | ||
- | People can be surprised by the pattern | + | This is indeed normal, it is the result |
- | This is indeed normal, it is the result of using polarised light. | + | Perfect alignment is reached when the lobes are more or less symmetric, that means they have roughly the same intensity |
- | {{:howto:backreflection_defocused.mp4|}} | + | {{:howto:backreflection_defocused1.mp4|}} |
The classic paper by E. Wolf " | The classic paper by E. Wolf " | ||
These figures are also reproduced in his text book if you have access to that instead. | These figures are also reproduced in his text book if you have access to that instead. | ||
- | Adding a drop of water on top of the cover slip reduces the back-scattering intensity by an order of magnitude or so, but the basic shape remains the same. Even if one removes everything extra from the beam path, these fringes remain there, they are universal. There are a lot of surfaces, coatings, etc., perfectly aligned in order to obtain such an image. Interferences are unavoidable, | + | Adding a drop of water on top of the coverslip |
- | Such images are used for the daily and fundamental alignment of the MicroTime 200. The detailed procedure is described in the user manual of MicroTIme | + | Such images are used for the daily and fundamental alignment of the MicroTime 200. The detailed procedure is described in the user manual of MicroTime |
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- | This article is based on a dialogue open in Researchgate | ||
- | "How can I properly align laser beam into the confocal microscope? " | ||
- | https:// |
howto/align_beam_backreflection.txt · Last modified: 2022/08/29 11:17 by peter