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发表于 2009-5-6 22:17:06
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Ok, I think I need to use English now since I had learnd everything about PIV in English.
The value M² represents the focusability of a laser. The lower the value is, the smaller is the beam waist, the smaller the divergence...etc. Therefor, the value is important for PIV experiments as we need a very small, defined thickness of the light sheet in the measurement volume. The better the M² value of the used laser is, it is easier to use the light sheet optics to produce a thin light sheet (ideal is around 1mm for planar PIV).
In complete I would say: the better the M², the better is the beam quality and divergence, the better the focusability, the thinner the light sheet, the more accurate the PIV results... |
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