laser power meter sper 840011

[Draco]

hello I was wondering if any one has service data for these hand held meters? i was to see if i can expand the range by about 10x for short times? that would give me rang to 400mw, i was thinking a voltage divider will work as i believe these just use a silicon sensor with a cheesy conversion chart for the curve of the sensor, it works great for sub 40mw lasers but with cheaper higher out put modules available now its getting limited in what i can use it for

[mixedgas]

Best to just get a calibrated beam splitter wedge or a 90/10 coated beam splitter. You could also use a very high grade Adsorptive Glass ND filter, but picking the right one is tricky. ND filters need to be calibrated.

For a wedge, the Fresnel reflection from each surface of air to normal, uncoated, glass is about 3.97% at smaller angles. It changes quite a bit with larger angles. So a thick or wedged piece of glass lets you separate out the two Fresnel reflections.

Wedges are nice because the two ghost beams come off at a decent angle. Flats have the beams very close together. Thicker flats give you more beam separation. IN A TIGHT SPACE YOU WANT THE WEDGE!

Flat:
http://www.surplusshed.com/pages/item/pm1041.html

Wedge:
http://www.edmundoptics.com/optics/p...e-prisms/27679

You might find a cheaper wedge at SurplusShed, Anchor Optics or on Ebay.

Steve

[Draco]

Thanks for the info, thats a lot easier to do then what i was planning lol