Laser 900nm

[khann]

Hi there , cool forum
Been looking and found nothing so far. I got laser rangefinder with wavelength around 900nm and glass in front of it (simple shield). Problem is that i got big refelection ( i used normal glass) and parameters are bad. Dou You gus maybe know how to solve it? Antireflection glass? where to get it?
Regs Mac

[absolom7691]

AR glass would help and I would image it would be better for the glass to be on an angle.

[khann]

AR glass would help and I would image it would be better for the glass to be on an angle.

Thanks - will try the deferent one
Do You guys think that kind of glass could do the job? http://effectglass.eu/eng/pobierz/ka...LEX-2013EN.pdf

[dsli_jon]

..you forgot to mention a lil' somthin..

AR glass would help...

...*provided-that* the AR-glass is, indeed, coated to transmit well at 900 and up.. For example, our 'beloved' CDAR, from Edmunds, starts to drop-off after about 700nm.. http://www.edmundoptics.com/images/catalog/5906.gif ..Don't know what it is at 900, but it the AR-properties could very-well drop off significantly after 800 or so..

....Do You guys think that kind of glass could do the job? ...

..Interesting stuff.. It appears (looking at the curves in their PDF, there..) that thier 'Low iron clear + DAGlass' coatings will give you about 95-ish% at 900nm.. not bad, but.. 5% is kinda highish for AR-glass, but, indeed, better than 'normal glass' (usually 8-9% or greater R..)

..The other factor I'd be wary of would be 'size / quantity'.. You're likely looking for a piece that's 15-20mm, tops, I'd guess, and that Manuf. is selling for much-larger applications.. So, you might be forced to buy a piece 10x the 'size' you need, and.. will a distributer even sell in a 'quantity of one'? Question to ask..

..I'd also be wary of the thickness.. If it's quite thick (3mm or greater..) the refractive properties might muck with your 'reception' on the detector-side, possibly even throwing the accuracy off.. Just something to consider before you go buy a bucket-load of it..

..These 'precision windows' should work well, 'curves-wise'.. http://www.edmundoptics.com/optics/w...-windows/45661 ...Not exactly 'cheap' but ..only 0.25% at 880nm.. and only 1.25% from 400 - 1000nm.. ..But again, not sure what the 4mm thickness (min-avail. afaik..) will do to your finder-accuracy.. (?)

..There's also this stuff: http://www.edmundoptics.com/optics/w...-windows/83102 ..But, the stuff is *super* thin / delicate, and only avail. in the 'VIS-0', which is *fantastic* for 445, but.. T-curves don't look so hot at 900mm.. :/

..So, you might try one of those 'precision windows' with the VIS-NIR coat, and see if the 'thickness' mucks with yer accuracy, etc.. Be sure and report your findings back to home-base.

cheers..
j

[kecked]

http://kinecat.pl/wp-content/uploads...rystal_ref.pdf

get a press and smash some calcium chloride or sodium chloride. makes great windows for ir. Sapphire works and some quartz. I work in the mid to far IR so ......