Absorptive ND2 filter

Hi,

I'm looking for an absorptive (not reflective) ND2 filter, do you have a reliable (really ND2 - 50%) source for such ?

So far I only found (ang got) reflective ND2 filters which are pretty dangerous to handle with lasers...

Thanks.

Not sure ..... anyway, ND are not 50%-pass optics, are 10%-pass optics ..... the 50% one that you mention are 1-stop photographic optics (they are 2 totally different scales, ND goes divide-by-10 each number, where stops goes difide-by-2 each number ..... like, ND2=10% pass, ND3=1% pass, and so on, where 1-stop = 50% pass, 2-stop =25% pass, and so on)

But, as far as i know, any decent ND filter is absorption type ..... the reflection of the faces are, as any other polished optics, almost impossible to avoid (can be AR coated, but a minimum of reflection can be always seen)

Or are you speaking about reflective beam dividers ? (that are mirrors that, at 45 degrees, pass 50% straight and reflect 50%)

I will tell you what I'm looking for, it will be easier

I would like to divide the power of a laser (any wavelength) by 2 to be able to measure ~1.5W laser on a 1W limited LPM.

That's is why I'm looking for an accurate (as much as possible) absorptive filter.

As far as I read a ND2 filter has a 50% transmittance (so it only lets 50% of the light pass through).

I bought this ND2 filter here: Ebay ND2 Glass Filter

Unfortunately it has a big reflection, when I point a laser through it the reflected beam/dot is strong. (whatever the angle of the filter is)

Are you aware of a place where could get a filter to achieve what I want to do ?

You could try to contact Lasersbee, I know I have asked a while ago about filters to use with my laserbee I, and he said he used a special type in his shop. That would be your best bet.

-Adrian

LOL, some of these sellers don't know what they write, on their auctions (look the "fader" rated for "ND2 to ND400" rotfl)

Anyway, yes, this one looks as a normal "1 stop" 50% uncoated neutral gray filter ..... but, as far as you find someone that make a broadband AR coating, there's no way for eliminate the reflection, cause usually these filters are NOT AR coated (still takes away 50% of the light, so is probably good, also if i don't know the optical curve of them)

For find better filters, you need to ask optic labs or specialized manufacturers, but this means higher costs (a lot higher ..... look at these ones, just for have an example ..... and Thorlabs are not the ones with the highest costs .....)

..... by the way, a 50% transmission, in the ND scale, is ND0,3 ..... ND1 is a 10% transmission, and ND2 is 1% transmission