Re: 405 laser intensity at the objective is 0.15% of actually intensity ... is this normal?

Posted by Peter Brunt AVR on
URL: http://confocal-microscopy-list.275.s1.nabble.com/405-laser-intensity-at-the-objective-is-0-15-of-actually-intensity-is-this-normal-tp7587264p7587290.html

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Hi Emmanuel,
For singlemode fibre coupling across multiple wavelengths ranging from 405-642nm I'd typically expect >60% coupling efficiency for all lines in the worst case.  For 405nm, 488nm and 561nm I'd actually expect closer to ~70% on the basis that most fibre coupling systems (industry wide) aren't entirely achromatic and the closer the wavelengths, the easier it is to adjust the coupling optics to maximise the efficiency.  

Still, if we assume there is still some loss on the dichroics, you should still expect ~54% average power out of the fibre.  I think there is a good chance your lasers / fibre coupler need realigning.  This is somewhat evidence by the fact that your coupling seems to be biased towards 561nm.  

I hope this helps.


Pete Brunt

AVR Optics