Hey Doc,
Yes, The Laserchecks differ from one another..
I am really not sure why..
Sorry not 3 percent accuracy..rated only 5.
But my experience has shown much worse.!!!
That was the test labratory enviroment conditions.
The first and second units I bought In 2000
+/- 5 percent.
They read 12mw different from each other at around 200mW at 658.
The third one I bought brand new Dec 04 from edmund qouted
+/- 5 percent ..reads a bit higher than the other two by 15mw
around 200mw at 658.
This is comparing them to both Scientech 365 and 373.
That is the reason I went with the Scientechs
Calibration is easy and repeatable. measurements are fairly quick.
(I can tune-up lasers with then)...It'l read down to a few tenths of a milliwatt.
with up to hundreths resolution.
Plus, now I can measure directly up to 30Watts.
My first Lab meter is a Liconix 55PM that is good to 300mW but is
wavelength sensitive...but very quick tuning.
I had it Cal'd at SE Laboratories in July 2000 for 488, 532, and 658nm.
All-in-All the Laserchecks are good , portable meters that give you an idea of the power involved...
But, If you want a solid , Kewl looking unit that will last a while..
Depending on what you are doing ...
I'd get a Calorimeter or Pyroelectric power meter.
Oh, the calorimeters are not buffered.. straight DC from the peltier..
Altho, the newer ones maybe..dunno.
You could make-up a meter, but why bother..they are so cheap on ebay..
as well as the heads...just keep waiting, they show-up every now and then.
"now , where did I hide the key to the Tardis"
"My signature has been taken, so Insert another here"
http://repairfaq.ece.drexel.edu/sam/laserfaq.htm
*^_^* aka PhiloUHF