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Dot suddenly bigger - what happened

borgqueenx

borgqueenx

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after hours and hours of aligning the dichro's today, i fired the 445nm up today, and suddenly the dot is alot bigger, even when removing the dichro's.

What could have happened?

i am really sad after all this work this happened :(
 





CDBEAM777

CDBEAM777

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A VERY minor radial movement in your collimination lens.....or a shift of the 445 LD in its holder ???? Either could change the distance from LD output to lens.....So....Might be a simple re-focus of the collimination lens. That would be very welcome !!
Are you using Anamorphic prisms to correct the beam astigmatism ??? Attach a pic of your set-up !! That would help to see how your set-up is layed out !!!

CDBEAM
 
borgqueenx

borgqueenx

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CDBEAM777 said:
A VERY minor radial movement in your collimination lens.....or a shift of the 445 LD in its holder ???? Either could change the distance from LD output to lens.....So....Might be a simple re-focus of the collimination lens. That would be very welcome !!
Are you using Anamorphic prisms to correct the beam astigmatism ??? Attach a pic of your set-up !! That would help to see how your set-up is layed out !!!

CDBEAM
Click to expand...

the diode in a heatsink...directly to the dichro's. no prisms...will a prism make the beam be normal again? is it adjustable? i was planning on buying such a thing anyways anywhere this month.

sorry i dont have alot of knowledge about lasers YET.
 
Cyparagon

Cyparagon

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It is a lens problem. Either move the lens in, or take the lens out to inspect it. If you're using the Aixiz lens, they have three components stacked (I think) and one of them comes loose from time to time. There is a retaining ring on the other side that might need to be tightened.
 
Meatball

Meatball

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If you're not running your diodes much past 200mA, they may be mode hopping, adding more modes to the output pattern, but if you're working with a PBS cube, I'm guessing you're driving them a bit beyond threshold. 1A or so?
 
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